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Madison, WI 53703
Mailing Address: Varies, see forms.
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201 W. Washington Ave.
Madison, WI 53703
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Katherine Koschnick
(608) 266-2112
Katherine.Koschnick@wi.gov

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S&B 2011 Commercial Electrical Q&A's

1. I am installing a 480 volt to 120/208 volt 25 KVA transformer. Is it OK to use the 8 AWG copper equipment grounding conductor run with the primary branch circuit to also act as the grounding electrode conductor for the secondary of the transformer?
Answer - No. See 2008 NEC 250.30(A)(3) and NEC 2011 250.121. While not clearly stated in NEC 2008, it has never been allowed. They serve two different purposes. They are sized differently, and equipment grounding conductors do not normally carry current, while grounding electrode conductor may carry current under normal conditions. NEC 2011 250.121 clearly states it is not allowed.

2. A customer has a manufacturing facility with a 1600 ampere 277/480 volt service. They are installing a new plasma cutting machine which requires an 800 ampere 480 volt supply. Because the existing service is not capable of supplying the added load, we would like to add a second service. Do we need to group the new service disconnect with the existing 1600 ampere service or can we locate it near the machine?
Answer - Either way. See NEC 230.2(C)(1), 230.2(E), and 230.71. Where the capacity requirements are greater then 2000 amperes, a second service is allowed by 230.2(C)(1) with out meeting the requirement for grouping of disconnects required by 230.71.

3. I used USE cable for an underground 200 ampere feeder from a barn to machine shed. The state inspector said I can not enter the building with these conductors. What’s the problem?
Answer - The code doesn’t allow it. Underground service-entrance cable, USE, cannot be used for interior wiring. It will have to be terminated outside and a conductor allowed in Table 310.13(A) used to enter the building. If using a cable such as USE/RHW, that can enter the building.

4. I am in the process of bidding a new medical clinic. Do I need to install “hospital grade receptacles” in the exam rooms?
Answer - No. The requirement for hospital grade receptacles is found in NEC 517.18(B) for the patient bed location in the general care area of a hospital, and in 517.19(B)(2) for the patient bed location of a critical care area. The listing instructions for some cord and plug connected medical equipment does require the use of a “hospital grade receptacle.”

5. A commercial building I am wiring has a small basement with only a sump pump and several lights. The inspector has indicated I need to GFCI-protect the sump pump receptacle or install a GFCI protected receptacle within 3 feet.
Answer - He may be thinking of dwelling unit basements where 210.8(A)(5) does require GFCI protection for all receptacles in an unfinished basement. Comm. 16.210(2)(b) allows a single receptacle for a sump pump where a GFCI protected receptacle is located within 3 feet. NEC 210.8(B) for “Other Than Dwelling Units” lists five areas where GFCI protection is required. (1) bathrooms, (2) kitchens, (3) rooftops, (4) outdoors, and (5) within 6’ of a sink. Basements are not listed.

6. Can I supply battery backup exit lights in an office building from an individual branch circuit?
Answer - Yes, with conditions. Battery backup exit lights are called “unit equipment.” NEC 700.12(F) indicates unit equipment is to be supplied from a branch circuit supplying the normal lighting in the area. The exception allows for a separate branch circuit in an uninterrupted area served by a minimum of three lighting circuits. T he separate branch circuit must be supplied by the same panelboard as the supplies to the normal lighting.

7. Am I requiried us to AFCI protect the lighting in a common hallway of an apartment complex I am wiring.
Answer - No. NEC 210.12 lists hallways as requiring AFCI protection. However, this applies for a hallway in the dwelling unit, not the common hallway.

8. They are remodeling a small room in our city hall for the health department to use for administering vaccinations. I feel it should be wired to comply with Article 517 as a patient care area. Am I wrong?
Answer - No. The scope of Art. 517 indicates the provisions of the Article apply to electrical construction and installation in health care facilities that provide services to human beings. The definition of a patient care area in 517.2 indicates any portion of a health care facility wherein patients are intended to be examined or treated. 517.13(A) requires branch circuits for receptacles and fixed equipment to be installed in a metal raceway or a cable having a metallic sheath or armor. The raceway or metallic sheath shall itself qualify as an equipment grounding conductor. 517.13(B) requires an insulated equipment grounding conductor, sized to Table 250.122 ,also be installed in the raceway or as part of a listed cable having a metallic armor or sheath.

9. I am installing a fire pump in an existing building. It will be located 50 feet inside the building, so I am planning on installing a fused disconnecting means on the outside of the building, sized to the locked rotor current of the motor. Then I will bring a listed 2-hour fire-rated assembly feeder to the fire pump room. Do the conductors need to be sized for the fuses in my disconnect?
Answer - No. See NEC 695.6(C)(1) and 695.7. The fuse is providing only short-circuit and ground fault protection for the conductors. Overload protection is provided through the listed fire pump controller. The circuit conductors are sized at 125 percent of the fire pump motor and pressure maintenance pumps and 100 percent of associated fire pump equipment.

10. We are bidding a 90-unit apartment building. Do we need to use tamper-resistant receptacles for the dishwasher and garbage disposal? The receptacle is located in a cabinet under the sink.
Answer - Yes. NEC 406.11 requires all 15 and 20 ampere 125 volt receptacles specified in 210.52 to be tamper-resistant. These are covered under 210.52-(1) through (4). NEC 2011 406.12 has an exception indicating tamper-resistant receptacles are not required where
1. More than 5 feet 6 inches above the floor or where part of a luminaire or appliance;
2. Where as part of a luminaire or appliance;
3. A single receptacle or duplex for two appliances located in a dedicated space;
4. Non-grounding receptacles used for replacements.

11. In a recent remodel project we installed several new raceways under roof decking to supply relocated light fixtures. We installed the new raceways 1.5 inches below the decking. However, they connect to existing junction boxes which are attached to the decking and to enter them we end up less then 1.5 inches from the decking. Is this is a violation?
Answer - Yes. The requirement for keeping raceways and cables 1.5 inches from the underside of roof-decking is to prevent long roofing screws from penetrating the raceways or cables. You could install box extensions or lower the boxes. NEC 2008, 300.4(E) only required raceways or cables on the underside of roof decks to maintain a distance of 1.5 inches below the decking. NEC 2011, 300.4(E) adds boxes as well as indicating cables, raceways, and boxes shall not be installed concealed in a metal corrugated sheet decking type roof.

12. I recently roughed-in a 12-unit condo complex. I used a two-inch PVC raceway from the top of the panel to the basement ceiling and ran my homeruns down it. The owner has decided to finish the room in the basement where the panel is located and the end of the pipe will become inaccessible above the ceiling. Is this going to be a problem?
Answer - No. While NEC 312.5(C) Ex. (b) indicates the raceway cannot penetrate a structural ceiling, Comm. 16.312(2) omits this requirement. Also Comm. 16.312(1) allows the raceway to be a minimum of 12 inches rather then 18 inches as the NEC requires.

13. Does a transformer need to meet the working clearances required by NEC 110.26(A)?
Answer - No. Small transformers do not normally have internal parts that require examination or maintenance while energized. Larger transformers may be checked for hot spots with thermo-graphic imaging. This may be performed with the doors or panels off or open. Working space would then apply to the area where access is made into the transformer. A safer solution is to specify glass “port-holes” installed by the manufacturer in the door or cover. Scanning or pictures may then be taken through the port-hole without removing the cover. Working space requirements have to be provided about equipment to permit ready and safe operation and maintenance of electrical equipment. Transformers do not require servicing while energized. Fusible switches, circuit breaker panels, and other equipment that are normally serviced while energized do need to meet the requirements of NEC 110.26(A).

14. By the time we were hired to wire a small manufacturing facility, the footings were already poured. The plans indicate reinforcing steel was installed in the footings and it is attached to the J-bolts for the steel columns. As they did not bring a re-rod out of the footing, can we bond to the building steel and satisfy the concrete encased grounding electrode requirement?
Answer - Yes. A concrete encased electrode is not required to be installed. However, if one is present it must be used. A concrete encased electrode is described in NEC 250.52(A)(3) as 20 feet or more of .5 inch or larger reinforcing steel encased by a minimum of 2 inches of concrete . Structural building steel that is connected to a concrete encased electrode is also considered a grounding electrode - 250.52(A)(2). 250.50 indicates all grounding electrode present at the building is required to be bonded together and becomes the grounding electrode system.

15. We are having a problem at a newly constructed parking garage with some of the PVC lighting conduits pulling apart at couplings. Do you think the glue was defective or is it poor workmanship?
Answer - Check for expansion joints. I assume this is an unheated garage. NEC 352.44 indicates expansion joints shall be installed where Table 352.44 indicates thermal expansion may be more the .25-inch. NEC 2011, 300.4(H) will also now require a listed expansion joint or other approved means to be installed where a raceway crosses a structural joint used for expansion, contraction, or deflection in buildings, bridges, parking garages, etc.

16. When using my new AFCI tester on required circuits in an apartment complex, some of the circuits would not turn off. When I told the contractor about the problem, he indicated he has an AFCI breaker installed and it trips when he uses the push to test button so he is done. What do I do now?
Answer - Nothing. Comm. 16.110 says the listing and manufacturing instructions indicate the use of the test button on the device is to be used for testing AFCI and GFCI devices.

17. I have been using 8/4 SER cable for 50 ampere circuits for years and now the inspector is telling me I can’t do it anymore. Is he correct?
Answer - Yes. NEC 338.10(B)(4)(a) indicates for interior installations use Art. 334 Part II. Prior to the 2008 code, you did not need to use the 60 degree C temperature limitations in 334 where your cable was rated for 75 degrees C. NEC 2011 will again allow the use of the 75 degree C rating when the cable is not installed in contact with thermal insulation.

18. I installed EMT conduit along the outside of a building to supply a new sign. Because NM cable was allowed in the building, I continued the new NM branch circuit through the conduit to the sign. The inspector indicated NM is not allowed to be used in a wet location, but I feel because it is in the conduit it is not in a wet location.
Answer - The interior of raceways installed in a wet location above grade are considered to be a wet location and conductors installed are required to be rated for a wet location. Unless the raceway is protected such that it is not in a wet location, you need to replace the conductors.

19. Our high school is moving some vending machines as part of a cafeteria remodel. When the local inspector did the inspection, she indicated we needed to GFCI protect the new branch circuits. I can understand if they were located outside, however these are in the cafeteria.
Answer - All new or remanufactured vending machines are required to include a ground-fault circuit interrupter as an integral part of the attachment plug or be located with 12 inches of the attachment plug. Older vending machines are required to be connected to a GFCI protected outlet, see NEC 422.51. Vending machines do not include ATM’s, or lottery machines.

20. We have a lot of confusion about where the disconnect is required for a dishwasher in an apartment. The owner would rather not have them above the counter because of tenants mistakenly turning them off . The the owner gets a call saying the dishwasher won’t work. It seems thedisconnect is upposed to be within sight of the dishwasher. Could I use 422.31(B) and put a lock on the circuit breaker?
Answer - You can’t use a breaker lock. NEC 422.32 indicates that for motor-operated appliances, if a switch or circuit breaker is used as the disconnecting means, it must be within sight. A dishwasher is considered a motor -perated appliance. 422.31(B) cannot be used to install a breaker lock. NEC 2011 422.31(B) has been rewritten to remove the language of more then 1/8 horsepower. 422.32 has been moved into a new 422.31(C) and clearly indicates if you have a motor-operated appliance of more then 1/8 HP the disconnect must be located within sight of the motor controller. T he switch could be located under an adjacent cabinet. If the receptacle is accessible, you could cord and plug connect it.

21. I am doing a service upgrade on an older home that had SE cable on the existing service. I don’t like SE cable, so I will be using raceway. However, I may need to use a 4-foot length of liquid-tight metallic raceway from the outside LB into the panel. Is there anything beyond the normal bonding requirements for service raceways I should be aware of?
Answer - Yes. NEC 230.43(15) allows metallic liquid-tight for service entrance conductors with an equipment bonding jumper routed with the conduit according to 250.102(A),(B), and (C). The bonding jumper must be copper or other corrosion-resistant material. The jumpers shall be attached as specified by 250.8 and sized using table 250.66

22. I’m bidding a small assisted living facility. Can I use NM cable as a wiring method?
Answer - Probably. Check with the owner as to how the facility is being licensed. A nursing home cannot use NM in patient care areas. A Community-Based Residential Facility or residential care apartment complex probably can. See 517.2 definition of patient care area, general care area, bedrooms, exam rooms, treatment rooms, clinics, and similar areas where patients can come in contact with nurse calls, electric beds, exam lights etc. Comm. 16.334(1) indicates NM cable is allowed in buildings of Type III, IV, and V.

23. We are installing receptacles at a large trucking company to supply block heaters for their trucks. I plan on using a single receptacle for each parking space and not GFCI protect them. I don’t want the problem of nuisance tripping. Will this be OK?
Answer - No. NEC 210.8(B)(4) indicates all 15- and 20-ampere 125-volt outdoor receptacles for other then dwelling units are required to be GFCI protected.

24. Do I need to mark a bare grounding electrode conductor green in some way?
Answer - No. NEC 250.62 indicates a grounding electrode conductor shall be insulated, covered or bare, but makes no mention of color requirements.

25. We recently had flooding in our community. If electrical equipment was underwater, can we just clean and dry it, or does it require replacement?
Answer - Replace it. See Comm. 16.110-(1). Most of the electrical equipment and wiring will require replacement if it has been submerged. The National Electrical Manufacturers Association and UL have guidelines. Any NM cable, switches, and receptacles will need to be replaced. Circuit breakers and panelboards will also need to be replaced. Wiring methods approved for wet locations may be able to stay if the ends have not been submerged. Meggering should be done on these items. Some large equipment may be able to be reconditioned by the manufacturer, depending on the length of submersion and contamination of the water.

26. I am installing an air conditioner unit. The name plate indicates the minimum ampere rating is 16.2 ampere and maximum fuse or circuit breaker is 25 amperes. I didn’t have any #12 AWG wire on the truck and when I called the boss to bring me some he said I could use #14 AWG. That’s OK?
Answer - Yes. NEC 240.4(D) Small Conductors indicates that unless 240.4(E) or (G) allows it a #14 wire can only be used at 15 amperes. 240.4(E) is for tap conductors and would not apply. 240.4(G) includes air-conditioning equipment. Table 310.16 allows a #14 AWG conductor to be used at 20 amperes at 60 or 75 degree C. 440.4 requires the minimum supply circuit ampacity and maximum protective device to be listed on the nameplat,e so all of the calculations have been done for you.

27. We are installing a 200 -mpere feeder to an outbuilding on a farm. Because of the distance, we determined we would need to increase the conductors from 3/0 copper to 300 kcmil copper to compensate for the voltage drop. Do we also need to increase the size of the equipment grounding conductor?
Answer - Yes. The equipment grounding conductor is required to be increased proportionately to the ungrounded conductors by NEC 250.122(B). Chapter 9 Table 8 indicates a 3/0 is 167800 cm. increased size to 300 kcmil. 300000/167800=1.7878. A #6 AWG is 26240 cm. 26240 X 1.7878 = 46911 cm. Chapter 9 Table 8 #4 AWG 41740 cm. This would require a #3 AWG copper.

28. The manufacturers of recessed light fixtures list the type of light bulbs that are approved to be installed within their fixtures. The newer type of medium base fluorescent light bulb is not listed for use in these recessed cans. Many people are buying them to conserve energy and are installing them in the recessed cans. Is this permissible?
Answer - Yes, this is permissible providing you install the lamp in accordance with it’s markings UL and do not exceed the wattage rating on the luminaire. The question is dealing with the proliferation of what the industry calls compact fluorescent lamps. UL Lists these as Self-Ballasted Lamps and Lamp Adapters, (OOKH), located on page 262 in the 2010 White Book. The Guide Information states these products have been investigated for use in the smaller of a 6- or 8-inch diameter recessed luminaire, if they will physically fit, and are intended for use in totally enclosed, recessed luminaires unless marked and stated not for such use.

29. A new commercial kitchen has a piece of kitchen equipment with a 20 amp, 125 volt twist lock connector. Is GFCI protection required?
Answer - Yes, NEC 210.8(B)(2) requires all 125-volt, single-phase, 15- and 20-ampere receptacles installed in kitchens to have ground-fault circuit-interrupter protection for personnel. There are no exceptions for a twist lock connector. Comm.16.20(2) has been deleted and all 15- and 20-ampere 125-volt receptacles in a commercial kitchen are now required to have GFCI protection

30. We recently installed a 60-ampere feeder to a small outbuilding. The owner only wanted one lighting circuit and one receptacle circuit in the building. I installed a small main lug panelboard and two circuit breakers. The inspector is telling me I have to install a main breaker. I feel I can use the 6 disconnect rule.
Answer - The inspector is correct NEC 225.31 requires a disconnecting means at the second building and 225.36 requires it to be suitable for use as service equipment. Comm. 16.110 tells us equipment needs to be installed following listing and labeling instructions. Most panelboard instructions indicate they are suitable for use as service equipment when a main breaker is installed. When breakers are back fed, they are required to be secured to the panel with a “hold-down” device per 408.36(D).

31. The grounding electrode system for a new office building will be the underground metal water pipe and the rebar in the footing. The service is 1200-amperes and conductors are three sets of 600 kcmil THWN-2 per phase and neutral. Can I take a 3/0 grounding electrode conductor to the water, then bond the water to the rebar with a 4 AWG? Do I still need two ground rods?
Answer - Yes. Bonding jumpers used to interconnect electrodes together must be installed per NEC 250.64(A),(B),and (E). The size is determined by 250.66. Since the maximum required size of an electrode conductor to a concrete electrode is 4 AWG copper, it follows that the bonding jumper would also be this size. Only underground water pipes need a supplemental electrode. The concrete encased electrode fulfills the requirement on this job.

32. I plan to run PVC conduit from an at-grade service to a new shop building. The feeder run is about 200 feet. Both structures are protected from frost. Do I need expansion fittings below grade? At the point where the PVC emerges above grade?
Answer - No, not below grade. Yes, above grade. See NEC 352.44, 300.5(J). The ground does not hold the PVC firmly in place. The PVC is free to expand and contract uniformly as the ground slowly cools down or slowly heats up. This is not the case above grade. The portion of conduit attached to the structure or enclosure mounted to the structure will not move. The portion below grade will move. The expansion fitting is required above grade to help ensure the conduit does not pull apart. This is also a common requirement of utility meter installation instructions. The expansion fitting may be required to help avoid damaging the underground conductors due to ground settling or other types of ground movement.

33. Does the electrical code require that openings in exterior walls be sealed in order to conserve energy? Or is this someone else’s problem?
Answer - Yes , the openings must be sealed. See NEC 300.7(A), Comm 22.37(3)(a)(4) 7 (b), and IECC 502.4.3. If the opening is yours, it is your problem to deal with.

34. I’m wiring pool equipment for a new hotel. Can I use a 2-pole, 50-ampere GFCI-Circuit breaker to protect the lights, receptacles, and pool equipment? The branch breakers would then be conventional circuit breakers.
Answer - Yes, you can. See NEC 680.22(B). The GFCI protective device must meet the requirements for personal protection. The trip setting must be 4 to 6 milli-amperes. You may experience “nuisance” tripping, especially if the branch circuit’s home runs are long. The GFCI device at the feeder level “sees” leakage current from the all downstream circuits.

35. Is it OK to use Table 310.15(B)(6) for sizing the conductors for a sub-feed panel in a residential dwelling? Is it OK to use the same table for sizing a 208/120-volt, single phase feeder to apartments?
Answer - Yes with conditions, and No. In the first case, the feeder must carry the entire load of the dwelling in order to use the table. In the latter case, only 240/120-volt feeders carrying the entire load of the dwelling unit may utilize Table 310.15(B)(6).

36. Is there a test to prove that an emergency system is selectively coordinated? What is the minimum that we have to do?
Answer - No, there is no test. Submit a one-line diagram of the emergency system. Include all overcurrent devices that are part of the normal and the emergency supply system. Submit time-current curves that show that all emergency system overcurrent devices are selectively coordinated with all upstream devices. There are two exceptions: 1. For overcurrent devices that are of the same ampere rating and are in series; and 2. For the overcurrent device that is on the primary of transformers and the secondary device, where only one overcurrent device or set of overcurrent devices is on the secondary. Submit proof that all ratings or settings required to achieve selective coordination have been completed prior to final inspection.

37. On a small office building I recently inspected they indicated there was reinforcing steel in the footing that was not brought out so they could make a connection to it for a grounding electrode. What they can do short of digging up the footing and chipping out the concrete to make a connection to the re-bar?
Answer - See NEC 250.52(A)(3). That would be one option. Another is to pour another “footing” next to the first with the electrode being made available for connection. It would have to be long enough to accept the required 20 feet of re-bar or #4 AWG bare copper conductor.

38. Are there special rules for pole top services? What we have is a 400 ampere Ronk pole top disconnect set-up for generator backup with lever handle at grade. We had a lug burn off over 4th of July weekend and need to replace or even up size to 600 or 800 amps. There are four 200a main breaker panels fed underground to this pole (these are spread out around camp grounds). Is there anything special we should be looking for?
Answer - Yes. A site isolation device (pole top disconnect) is only permitted to be installed on agricultural facilities in compliance with Article 547. You have indicated this equipment is being used for campground distribution. RV sites and campground wiring shall comply with NEC Chapters 1 thru 4 and Article 551. Use of a site isolation device for this purpose is not permitted. A grade level service complying with Article 230 is required. RV sites and campsites shall be supplied by branch circuits and/ or feeders.

39. I have a local township that is building a wash bay for their trucks. It is a wood building with metal siding inside and out. Can I use NM cable to wire this building? It will be installed inside the walls. For receptacles that will be weather proof ( in use covers) and vapor tight lights. Would you call this a commercial garage? The architect called it a Type S-1 storage building.
Answer - Maybe you can use the NM cable. Yes, it is a commercial building. If they are not doing repair work on vehicles in which flammable liquid are used for fuel NM cable would be allowed. NEC 334.12(A)(4) indicates NM cable cannot be used in commercial garages having hazardous locations. 511.3(A) indicates parking garages shall be permitted to be unclassified. A type S-1 building allows repair garages, while limiting quantities of hazardous materials. If they are only using the building for washing, it does not have any classified locations.

40. Do the wire colors in fixture whips need to follow the requirements of 210.5 C or could a factory-made whip with black, white, and green be used on 277 volt lighting with brown, orange, and yellow phase conductors with a gray neutral? And does it matter if they are factory-purchased or made in the field?
Answer - The requirement in NEC 210.5(C) applies to all ungrounded conductors of the branch circuit, including fixture whips that are not part of a listed fixture assembly. This could be done by color coding, marking tape, tagging, or other approved means. The method used shall be posted at each branch circuit panelboard. It does not matter if they are factory-purchased or made in the field.

41. The local township and the fire department have two buildings about 20 feet apart. They have separate services for each building. Can I install one generator for emergency power to feed both buildings? What code articles should I be most aware of?
Answer - Yes, You can. See NEC Articles 225 and 700. Article 700 is the applicable article to look at for the installation. Some things to remember is the generator will have to be sized to carry the calculated load. You indicate you have a separate service in each building, so you will need a transfer switch for each building or a means to monitor both normal supplies. It can only supply emergency lighting unless a separate “optional” standby system transfer switch is installed. All emergency circuits would be required to be in listed raceways, of MC or AC cable. Normal electrical circuits cannot enter any raceways or junction boxes with the emergency circuits. You should also look at NFPA 110, Standard For Emergency And Standby Systems for additional requirements for emergency systems.

42. We need to install an electrical control cabinet approximately 38 inches wide by 5 feet high with 480 volt motor control inside. About the only installation location that works is in an area that will have occasional fork truck traffic. However, there is not enough physical space to provide for both the working space requirements of table 110.26(A)(1) and the fork truck. Can a removable guardrail or a swing gate type guardrail be placed within the working space in front of the cabinet?
Answer - Swinging gate, yes. Removable guardrail, no. NEC 110.26(A) indicates equipment which may need servicing or maintenance while energized is required to have clear working space as required by the following:
(1) depth as indicated in Table 110.26(A)(1). 36 inches;
(2) minimum of 30 inches or the width of the panel, in this case 38 inches;
(3) height of the equipment; as required in (E) 6.5 feet or height of equipment, if greater the 6.5 feet;
Also overcurrent protective devices must be readily accessible per 240.24(A). A swinging guard that functions as a door would be allowed as long as the panel was still deemed readily accessible. For example, a hinged or swinging guard could not be bolted shut or locked shut. It could be located as close to the panel as you choose, as long as it meets the clearance requirements when open.

43. I have an open office space in a commercial building where the installed 20A/120V branch circuit is drawing 23A. The load is linear fluorescent pendant fixtures and recessed cans, all fixed lighting units. To remedy the situation, I have specified a 30A/120V branch circuit breaker to accommodate the load. The circuit is to be fed with #10 wire. The code section I am wondering about is 210.23(B). What constitutes a “heavy duty lampholder”?
Answer - You can’t do it. NEC 210.21(A) indicates a heavy-duty lamp holder has a rating of not less than 600 watts, if of the a medium type, and not less than 750 watts, if of any other type. I have not seen any fluorescent sockets that would meet these specifications, thus you are limited to a maximum 20-ampere circuit to supply fluorescent or medium base fixtures.

44. Would it be permissible to install an F Bay fixture with a modular cord and plug from the manufacture in a major repair garage where the floor is classified? Or would the cord be considered as part of the fixed wiring as specified in 511-7(A)1? The fixtures would be mounted at a height exceeding 12 feet. The listed cord type from the manufacture is listed as type STW.
Answer - Yes and No, NEC 511.7(A)(2) allows flexible cord to be used for pendants above the Class 1 location. I don’t have a good definition of a pendant and although this isn’t what I would typically think of as a pendant, it is similar and would be allowed. You indicate it is a Type STW, which is listed for extra hard usage. It would be required to be installed to meet 410.62(C). The requirements found in 511.7(A)(1) would apply to the circuit supplying the cord.

45. I’ve got a new 200 -mp service on a treated pedestal with a service disconnect, all rated for service and exterior use. Do I have to provide a bonding terminal for other system.
Answer - It’s OK without installing a terminal bar per NEC250.94 and PSC 114.099. If no other systems are present or planned for, you would not need to supply the intersystem bonding terminal at the service equipment.

46. Could you please tell me how long (seconds) it should take a generator to transfer?
Answer - Ten seconds for emergency, 60 seconds for legally required, and no time limit for optional systems. See NEC 700.12, 701.11, 702. Emergency generators must transfer power within 10 seconds per 2008 NEC, Section 700.12. If the generator only supplies legally required loads, such as exhaust fans or fire pumps, it may take up to 60 seconds per Section 701.11. There is no required transfer time for generators supplying optional loads, per Art. 702.

47. I am bidding on the wiring for a new Community-Based Residential Facility. I spoke to the owner about the type of health care they provide. The residents are not sick, but will get some basic care. This may include equipment such as oxygen generators and nebulizers. I need to know if this type of care will require the wiring to comply with Article 517.
Answer - No. Assisted living providers are designed to provide a balance of institutional and residential physical plant requirements. The Wisconsin Department of Health Services’ position regarding the application of NEC Article 517 Health Care Facilities to Community-Based Residential Facilities and Residential Care Apartment Complexes is that they do not provide “health care” in the traditional sense. Architecturally, the DHS continues to support the position that C-Class CBRF’s are best suited for an IBC Use Group I-2. This is consistent with the International Building Code (IBC) formal interpretation 16-03, primarily due to the resident’s inability to respond to a fire alarm notification and require help verbally and/or physically to exit the facility. Plumbing requirements per Comm 82.50 are also supported by the DHS, primarily due to the age, infirmity, and scald potential of the CBRF residents. With respect to the electrical code, assisted living residents are provided nursing services and could fall under the definition of a Health Care Facility found in NEC Article 517. Yet, the facilities are not well suited for application under the definition of Patient Care Areas. Given the limited amount of medical and personal equipment requiring double grounded circuitry, the DHS is not in favor of having CBRF’s or RCAC’s fall under the scope of NEC Article 517.

48. The project I’m working on has an 800-ampere service. The service equipment is an Eaton-Cutler Hammer PRL panelboard. It has factory installed surge protection (SPD). The issue is the circuit breaker ahead of the SPD. There is a dead front that is bolted to the frame with two side covers that bolt to the dead front and panel tub. The circuit breaker in question is located behind the dead front. Don’t’ circuit breakers have to be readily accessible?
Answer - Typically, yes, per NEC 240.24(A)(3). However, this device is supplemental and is therefore permitted to comply with 90.7 and 240.10. The key piece of information is that the SPD was factory installed, integrated into the panelboard construction, and the circuit breaker supplies only the SPD. NEC 90.7 indicates that it is the intent of the NEC that factory-installed internal wiring or construction need not be inspected at the time of inspection. This type of issue is address by the listing standard which is used by the manufacturer to construct the equipment. The construction appears to comply with the UL 67 standard and should be good to go. Since the switch/CB is only for the control of the SPD and not the main, feeder ,or a branch circuits that leave the panel, then it is permitted to not be accessible.
The requirement in UL 67, the Standard for Panelboards states that: 12.1.5 A switch or circuit breaker provided to control a main, feeder, or branch circuit shall be capable of external manual operation under rated load conditions. Operating mechanisms of switches and circuit breakers located behind doors or covers shall be considered capable of external manual operation so long as the mechanism may be accessed without the use of a tool. Provisions for locking a cover are not to be considered as restricting access for external operation. An electrically operated switch or circuit breaker need not be capable of being externally operable by hand to the closed position. Circuit breakers that provide overcurrent protection for feeders and branch circuits and overload protection for service conductors shall be readily accessible per NEC 240.24(A).

49. I know the rules are being enforced for Emergency Lighting Testing as of April 1, 2009. Other contractors are not doing the testing. Why does my inspector force me to send a report?
Answer - I’m not sure. NEC 700.4(A) requires that the Auathority-Having-urisdiciton to conduct or witness a test of the entire emergency system. NEC 700.4(D) requires that a written record be kept of such testing. The requirements for the means of egress illumination are found in the Commercial Building Coder, IBC-1006. T he minimum at any point along the means of egress in 0.1 foot-candle and the average is at least 1 foot candle. Don’t forget to provide emergency illumination on the outside of required exterior exit doors.

50. I worked in a new C-store that opened two months ago and was surprised not to find any AFCI breakers installed in it. Someone told me that AFCI protection is required and has to be used everywhere. What’s the story?
Answer - The NEC-210.12 erquirements for AFCI protection for branch circuits did become effective on January 1, 2010. However, the requirement is limited to branch circuits supplying lighting and receptacle outlets in certain areas of dwelling units. I t is further limited to 15- and 20-ampere, 120-volt branch circuits. A store is not a dwelling unit, so the requirements do not apply. There is no proposed change in the 2011 NEC that would extend the AFCI protection to non-dwelling occupancies.

51. I am installing a new service for machine shop. My power company would not give me the available fault current at the service point unless I paid them $500 for the calculation. Can they charge me?
Answer - Yes. You must know the available fault current in order to select the service equipment. Overcurrent devices such as circuit breakers and fuses have a marked interrupting rating. Installing such a device on a system where the available fault current is higher than the rating is unacceptable and dangerous. It is not a value you can calculate for yourself unless you have sufficient information about the system. The 2011 NEC will require that the available fault current be field marked on service equipment serving non-dwelling occupancies.

52. My ex-brother-in-law bought an old block and brick supper club and is remodeling it. He wants me to wire it in Romex. I think it is a Class II building and bid it in EMT. My competition is bidding it in Romex. Who is correct?
Answer - The competition. Your competition has done their homework. The class of construction does have an impact on the type of wiring method. We will assume the capacity is 100 persons or more. So that the building is meets the definition of”Assembly” occupancy. NEC 518.4 sets the requirements for wiring methods. 518.4(B) does permit nonmetallic cables in “Non-rated” construction. “Non-rated” construction is defined for the purpose of applying the electrical Code in Comm 16.100-(1)(c). It includes building Types III, IV, or V. While there is not enough information for us to determine the type of construction, it is very likely that it is Type III, IV, or V. Essentially all of the walls, floors and structural framing in a type I or II building is non-combustible. Check with you brother-in-laws architect, general contractor or the local building inspector for additional information. Good luck with your bid!

53. Due to the new anti-smoking rules our church/meeting hall/social club is adding an enclosed fixed screen porch. The screen porch is 15-feet by 30-feet and has two exit doors to the outside. It gets really crowded on poker night. Does this space require exits signs and emergency lighting?
Answer - Yes. Exit access doors shall be marked with an approved exit sign readily visible from any direction of egress travel. There are several exceptions including one for rooms or spaces requiring only one exit. This space has two exits. The International Building Code 1006.3, as adopted in Wisconsin, also requires an emergency source of power for means of egress illumination in rooms or spaces that require two or more exits. A minimum emergency lighting installation would illuminate the exit aisles within the space as well as the area on the stoop or landing on the exterior side of each exit door. I f there are no defined aisles, there entire portion of the space where individuals could use to walk out of the space would have to be covered.

54. Why doesn’t the State of Wisconsin require electrical plan review? Plan review is required for all of the other construction disciplines.
Answer - Plan review is presently not mandated by law. There are several aspects of electrical construction that do require plan review. The state does require energy calculations, lighting control information, and emergency lighting plans for new buildings, building additions where the total building volume exceeds 50, 000 cubic feet ,and first-time tenant space build-outs in such buildings. The state also requires an electrical plan review for all new house construction where state staff review the construction plans. The Department of Health Services requires short-circuit and coordination calculations for any hospital or nursing home construction that involves the essential electrical system. Local inspectors may perform that review, if they willing. Otherwise, state staff up do those reviews. In any case, the electrical plans can be submitted to the state for review upon request. There is a fee charged for that service. The state does plan to review electrical plans for fire pump installations.

55. Can you update us on the Department of Safety and Professional Services plans for the future?
Answer - The Safety and Buildings Division has proposed a plan to provide for state-wide inspection of public building and farms. This inspection program was mandated by Wisconsin Act 62, the same law that requires the department to license electricians. We anticipate that this program could be in place prior to 2013. In conjunction with the inspection program, the division plans to audit agent municipalities and private inspection agencies in order to ensure uniformity. The division will continue to support educational activities, in particular the yearly update program. S&B staff will continue in 2011 to coordinate and provide exam preparation classes in the rural areas of the state. Staff will also remain available for Answering code questions, investigating complaints, and provided needed inspections.

56. We recently added a Solar PV array to the roof of an office building. The electricity generated by the array is sold back to the utility. The owner’s electric bill is essentially reduced by the amount of power they generate. There is a separate meter and service disconnect. We located the service disconnect for the PV unit on the exterior of the building at the utilities request. The building service is located inside. The local inspector thinks both disconnects have to be grouped. Is the exterior location for the PV disconnect OK?
Answer - Yes. The general rule in NEC 230.40 requires the service drop or lateral to supply only one set of service-entrance conductors. When you added the PV meter and service disconnect, you added the second set of service-entrance conductors. Therefore, one of the exceptions must apply. Exception No. 2 is the one that the inspector is thinking of. It allows up to six sets of service conductor supplying up to six service equipment enclosures grouped at one location. We think that Exception 5 fits your application. It permits an additional set of service-entrance conductors to supply each or several systems covered by 230.82(5) or 230.82(6). 230.82(6) permits solar photovoltaic systems to be connected to the supply side of the service disconnecting means.

57. I have wired a metal fabrication facility with a designated paint spray area. They only use water-based paints. The owner has installed an approved ventilation system. OSHA has written him up for having EMT raceway as a wiring method. Is OSHA correct?
Answer - No. The NEC is used by OSHA as the normative standard for electrical wiring. OSHA does not recognize local amendments to the NEC. 29 CFR Part 1910 draws heavily from the 2002 NEC. Sec. 1910.307(a) covers Hazardous (classified) locations.
“1910.307 (a) Scope - (1) Applicability. This section covers the requirements for electric equipment and wiring in locations that are classified depending on the properties of the flammable vapors, liquids or gases, or combustible dusts or fibers that may be present therein and the likelihood that a flammable or combustible concentration or quantity is present. Hazardous (classified) locations may be found in occupancies such as, but not limited to, the following: aircraft hangars, gasoline dispensing and service stations, bulk storage plants for gasoline or other volatile flammable liquids, paint-finishing process plants, health care facilities, agricultural or other facilities where excessive combustible dusts may be present, marinas, boat yards, and petroleum and chemical processing plants. Each room, section or area shall be considered individually in determining its classification. Note to paragraph (c)(3) of this section: The National Electrical Code, NFPA 70, contains guidelines for determining the type and design of equipment and installations that will meet this requirement.
This is similar to the scope of Article 516 Spray Application, Dipping, and Coating Processes. “This article covers the regular or frequent application of flammable liquids, combustible liquids and combustible powders by spray operations”.
The spray operation uses water based paints. Water is not a flammable or combustible liquid. If no combustible powders are used, the owner could appeal the determination.

58. I installed a NEMA-3R panelboard in a new free stall barn. The inspector said I have to move it outside and put in a NEMA. 4X or 6P panel. The wall panels open and there is a lot of air movement. Do I have to move it?
Answer - Possibly, based on NEC 547.5 (C)(2) and (3) and 110.20. Adequate ventilation must be present at all times to prevent corrosive damage to electrical equipment. In this is the case, a NEMA 3R enclosure may be acceptable. NEC 547.5(C)(2) pg 464, requires that enclosures in damp locations be placed or equipped so as to prevent moisture from entering or accumulating in the enclosure. Table 110.20 pg. 35 address enclosure types which provide a degree of protect ion against various environmental conditions. Type 3R enclosures provide protection against rain, snow, and sleet. 547.5(C)(3) covers corrosive areas on farms. Electrical enclosures rated for such areas are Types 3RX, 4X or 6P. An example or such a room or area is in the immediate vicinity of manure handling equipment.

59. My local co-op has installed a new service pedestal for my new mobile home that is 50 feet away. The inspector says I need to install another service-rated disconnect with 30 of the mobile home. Do I also need to tie the grounding electrode conductor into the concrete grade beam that supports the home?
Answer - NEC 550.32(A) covers the mobile home service equipment. One option is to locate the service equipment within 30 feet and within sight of the home. A second option is to locate a disconnecting means that is suitable for use as service equipment to meet the same requirement. Grounding at this disconnecting means shall meet 250.32. NEC 250.32(A) requires a grounding electrode system be installed. If the concrete grade beam contains rebar and meets 250.52(A)(3) requirements, the grade beam is an electrode and it must be used. No additional electrode, such as ground rods, are required if the disconnect is connected to the rebar in the grade beam.

60. I understand that in the new 2011 NEC that hotel and motel rooms will have to meet the AFCI requirements.
Answer - Not unless the room is a dwelling unit by definition. If the room is a dwelling unit, then yes, both 2011 NEC 210.12 and 210.60 apply. Note that in either case 2011 NEC 406.13 will require the installation of tamper-resistant receptacles.

61. I have been asked many times as an inspector to help out a contractor or engineer/designer to solve a 110.26(C)(2)(a) area problem by saying the site has an unobstructed egress path. What would be a good rule to work with on an explanation that I can use?
Answer - Use NEC 110.26(C)(2)(a) pg. 37. In other words: face gear, turn around 180 degrees, and leave area by not meeting any obstructions.

62. I am wiring a 42-room motel. The plan shows a receptacle located on a wall where the bed is to be located. The the receptacle has to be “protected” and could use a bubble cover on it. It wouldn’t look very good. Any other solution?
Answer - See NEC 210.60(B). A protective cover is one possible solution. Relocating the receptacle so it isn’t behind the bed might be more practical.

63. I understand that the new energy code requires us to install a new master switch to kill all power to lights in a given area.
Answer - See NEC 210.70(B) and Comm. 63.1050, Commercial Building Code. Four types of controls: 1) Area, 2) Reduce lighting, 3) Day lit areas, 4) Shutoff.

64. NEC 210.11(B) talks about loads to be proportioned among the branch circuits. H ow close do they have to be?
Answer - Webster’s dictionary defines “proportional” as “having the same or constant ratio”. Often a major objective in agricultural facilities, minimizing the neutral current is the objective.

65. I know the rules for generator and power transformer locations. Do they apply to an NEC Article 702 optional system?
Answer - No, separation only applies to emergency and legally required standby. See Comm. 16.700 and 16.701. The minimum 20-foot spacing is not required between transformers and generators that supply only optional loads, but you could use it as a good rule of thumb.

66. I have a question on a proposed emergency system design. To meet NEC 110.9, the upstream feeder circuit breakers on both the normal and generator side provide the entire band of overcurrent and short circuit protection. I propose to use a molded case switch for isolation purposes on the line and load side of the transfer switch. Would this meet Exception 2 to NEC 700.27?
Answer - Yes, if of similar ampere rating. See NEC 700.27. I am assuming the switch has a short circuit current rating that equals or exceeds the available short circuit current, and that you have selected an instantaneous rating or setting that allows the load side device to clear first. The NEC does not directly address the issue. For example you could put a 800-ampere fuse and 800-ampere circuit breaker in series. They could have very different time-current characteristics. The exception only refers to size determined by the ampere rating.

67. We will be doing a remodel of a fast food restaurant. Kitchen equipment will be moving to different locations switching around circuits to newly built interior walls. Sinks will be located on the same walls as appliances such as soup warmers , hot fudge warmers, and refrigerated worktables. Do all receptacles for this equipment have to be GFI protected, or just receptacle near the sinks? If so what about refrigerated work tables if receptacle is low?
Answer - Yes, all recptacles. Section 210.8(B)(2) of the 2008 NEC indicates all 125-volt 15- and 20-ampere receptacles in commercial type kitchens are required to be GFCI protected. All receptacles meeting the amperage and voltage requirements indicated would require GFCI protection.

68. I have a couple of questions for you regarding the code requirements for a maxifascial surgery center that I am beginning the design work on. I will be using emergency power for my life safety branch and for my equipment branch. I will be staying under 100 kW for the 6 treatment rooms that will require emergency power. Can I feed the life safety panel and equipment panel from one transfer switch? Will I need all GFI receptacles in the treatment rooms?
Answer - Yes, to one transfer switch, per NEC 217.45(B) and 517.30(B)(4). No, not all receptcles in treatment rooms are mandated to be GFI, per NEC 210.8(B)(5) Ex. #2 and 517.20. To be more specific, more information is necessary.
The use of a single transfer switch for the essential electrical system of the center may be allowed by 517.30(B)(4) which would allow the use of one transfer switch to serve one or more of branches of the essential system where the maximum demand is 150 KVA or less. When looking at the essential system it is important to determine what is going to be installed. The loads would be limited to the items addressed in Article 517 for the essential electrical system.
You could not supply loads that do not meet one of these requirements from the single transfer switch. If other loads were supplied they would be considered part of an optional standby system, Art. 702, and an additional transfer switch would be required for those loads.
517.20 requires GFCI protection for all receptacles installed within a wet procedure location. 210.8(B) requires GFCI protection for receptacles located in bathrooms if the treatment rooms would have their own bathroom.

69. We have a number of printing presses in our facilities and, therefore. rooms that are used for storage or mixing of inks and solvents. We rate our mixing rooms as Class 1 Div 1 and our storage rooms as Class 1 Div 2. Around our printing presses out on the production floors we follow the requirements of Article 516 (although we are not actually spraying or dipping). As shown in article 516, as you get further away from the hazardous material, the hazardous area is reduced in height to an area three feet above the floor. Why in our hazardous storage rooms do we need to rate the area above three feet as hazardous? The hazardous material is all heavier than air.
Answer - I would use NEC 500.4 to require documentation from a qualified engineering firm or individual who is experienced with the classification of flammable materials and their use. The classification of the storage area as Class I Div. 2 may be appropriate, assuming the criteria in 500.5(B)(2) is met Without the proper documentation I would assume the entire area to be classified.

70. How far we need to provide egress (and normal) lighting out an exit?
Answer - IBC 1006.3.5, as adopted by the Wisconsin Commercial Building Code, requires that the exterior landing for exit discharge doorways be automatically illuminated by the emergency electrical system. 1008.1.5 stipulates the minimum dimensions of the landing. For example, the required width of the rear exit door for tenant space “A” is 36-inches. The minimum depth of the landing in the direction of travel is 44 inches. In this case, the area requiring illumination from an emergency system is 36 inches by 44 inches, regardless of the size of the concrete pad.

71. We are looking at an MRI room witch I believe falls under a patient care area, when looking at page (70-426) Article 517.2 definitions. Patient care vicinity page (70-427) describes a space within the room not less than six foot beyond the perimeter of the bed, in its normal location. In an MRI room patients are escorted in, placed on the table, receive the MRI, and are escorted out. If the outlets in the MRI room are outside of the six foot perimeter around the bed, do they need to have a redundant ground?
Answer - Yes. The starting point is the definition of patient care area. The requirement for metal raceways or cables and the additional equipment grounding conductor is in NEC 517.13. This requirement applies to receptacles and fixed equipment in patient care areas. There are areas within a MRI room where the definition fits. Any area where the patient may come in contact with ordinary electrical appliances. There may be other areas in the room where the patient is restricted from accessing this type of equipment due to barriers or the attendant. The area designated for patient care is determined by the administrator of the facility. Without such a determination, I would generally classify the entire room as a “patient care area.”

72. I am an electrical engineer working on a new rehabilitation facility. We would like to have a small natural gas generator for each building that would be the only fuel source. This generator would serve some receptacles, emergency lighting, and some HVAC equipment. I think this is allowable by code if the authority-having-jurisdiction approves it, per NEC 700.12(B)(3) exception. Do you see this as a problem?
Answer - See NEC 700.12(B)(3). This is an interesting question. I think natural gas is considered to be a reliable fuel source. I have heard the state Department of Health and Family Services may disagree in that they feel their adoption of NFPA 99 would support that an alternate on-site fuel source would be required. S&B enforces what Comm. 16 and the NEC indicate. I would also take into account that you are a Wisconsin registered professional electrical engineer making a supervising professional determination for the project.

73. I am working on a project where we are installing two UPS modules in the data room. NEC Article 645.11 requires that both the input and output of the UPS be disconnected with the operation of the EPO switch. The UPS we are looking at has a contact within the cabinet on the input power. If this contact is opened with the activation of the EPO switch and input power is disconnect at this point, will this comply with 645.11 or does the breaker in the feeder panelboard have to be opened shutting off power to the feeder conductors?
Answer - NEC 645.11 tells us that if you do not meet (1) or (2) you need to comply with 645.10. In 645.10 you are required to disconnect the power to all electronic equipment in the room. This would require disconnecting the circuit to the UPS, be it a feeder or branch circuit. Opening the contact in the unit would not disconnect the power to the unit. Some units have a dry contact in the unit that is usually used to operate a shunt trip breaker feeding the unit.

74. Does an LED fixture that consists of multiple diodes and one driver satisfy the intent of the requirement in NEC 700.16 for multiple lamps in regards to exterior egress illumination?
Answer - Yes. A single driver is permitted. A single LED lamp would also per permitted as the sole source of emergency illumination. The failure of one of the emitters will not compromise the entire lamp. This is similar to consideration of fluorescent luminaires and exit fixtures. NEC 700.16 requiries two tubes, but only one ballast in an area where the fluorescent fixture is the sole source of emergency illumination.
There is no reason to treat an LED driver any different than a ballast. LED drivers are, by and large, manufactured by the same firms that produce ballasts and power supplies. The LED driver industry is continuing to evolve towards greater product longevity and improved lighting performance. As in any industry and especially those growing quickly, there are opportunities for lower-price competitors to participate and it will take some time for the marketplace to filter them out.
It is to apply NEC 700.16 to LED luminaires in the same manner as it is applied to fluorescent. Presume failure of “an individual lighting element.” The example given in the NEC text (“such as the burning out of a lamp”) could very reasonably be extended to the failure of an LED lamp, tube, or array. If Wisconsin does not apply this presumed failure mode to an electronic fluorescent ballast, there is no reason to apply it to an electronic LED driver.

75. We have a new grocery store being built here. There is a generator installed with one transfer switch to handle both legally required and the optional loads in case of a power failure. However, if the main trips due to a ground fault the generator will not start, leaving the entire building in the dark. Is 701.18 Selective Coordination the only help in reducing the risk of this happening?
Answer - This involves several serious issues. I am not sure what you are referring to as legally required loads. Legally required loads are items that Chapter 27 of the building code would require to be on standby power such as smoke control systems, accessible means of egress elevators, sliding doors, etc., and are required to be installed per Art. 701 of the NEC. Emergency egress lighting is required to be installed using Art 700. NEC 700.9(B) requires emergency circuits to be kept entirely separate from other non emergency circuits. This would require the use of separate transfer switches if supplying non emergency circuits. If only one transfer switch is being installed, and is used to supply loads other then emergency lighting, some other means of emergency egress lighting would need to be installed such as unit equipment. You are correct in referring to NEC 701.18 for a legally required system. 700.27 for an emergency system would require the systems to be selectively coordinated. In either case, if the normal system fails, the generator should start and automatically transfer. The emergency system would need to transfer within 10 seconds and for the legally required system within 60 seconds. Loads not considered emergency or legally required are optional and installed per Art. 702.

76. I am currently working on a project that is using LED lighting as its lighting source. This is residential construction utilizing LED strip fixtures and recess cans. How they are being wired is with a remote power supply that has 120 volt input and RJ45 phone jacks for control to the switch/dimmer and power supply to the LED lights? Are the Category 5 cables suitable as a wiring method under the NEC as a supply conductor to LED fixtures? Are the fixtures permitted to be installed in a shower area (wet location) or over a spa/tub (damp location)? The LED fixtures are less than 8 ft above the water surface. This entire wiring configuration is UL listed and approved.
Answer - GFCI protection is not generally required for fixtures of any type that are installed in damp or wet locations. The fixture must be marked for the locations per 410.10. Fixtures in bathtub and shower areas must meet 410.10(D). There are some locations, such as around swimming pools, spa, and hot tubs, where providing GFCI protection allows the fixtures to be closer to the water.
The suitability of the Cat 5 cable as a wiring method for the LED fixtures must be addressed by the listing. The installation instructions for listed lighting system address the size and type of permitted cables. The type of cable permitted is often based on the output capability of the power supply. For example, the power supply may be listed as a Class 2 power supply. Cables shall meet the listing requirements from Article 725, including the permitted substitutions. For example, the Category 5 cable may be used with a Class 2 power source as long as it listed as “Type CM” and is the proper wire gauge. NEC 680.43(B) addresses the installation of light fixtures over an indoor spa or hot tub.
680.43(B)(1)(c) indicates the requirements for lights that are located less then 7 feet 6 inches above the water. 680.41(B)(c)(1) and (2) indicate the luminaires should have a glass or plastic lens and non-metallic or electrically isolated metal trim and be suitable for use in damp locations. These rules apply for recessed luminaires as well as surface mounted lights.
Also 680.43(B)(1)(a) requires lights located less the 12 feet above the water to be GFCI protected. A GFCI on the line side of the power supply would not protect the secondary side. I do not know how the secondary side could be protected. I would look for a unit that would have GFCI protection on the load side included as part of the listing. It appears the installation you describe would not meet these requirements.

77. I am under the impression that illuminated exit signs are required to be wired with a metal conduit/cable. Is this true? I believe it was required by the International Building Code.
Answer - No. IBC 1011.5.3 and 2702.2.3 require exit lights to be supplied by an emergency source for a minimum of 90 minutes in the event of loss of normal power. This can be provided by storage batteries, unit equipment, or an emergency generator. Comm. 16.700(1)(a) requires emergency circuit wiring to be installed in a listed raceway or Type AC or MC cable. Remember, when using unit equipment the emergency circuit begins at the battery and would not require a raceway to supply the unit equipment itself. However, if you are supplying a remote head, raceway would be required to the remote light.

78. I have a question for a fire alarm system wiring. The owner would like to spray the open ceiling area an off- white. The area already has red fire alarm cable in it. Will it be ok if the cable is painted?
Answer - Yes, unless the cable is listed CI cable. See NEC 760.154. By cable I’m assuming you’re referring to PLFA circuit wiring which is required to be identified at terminal and junction locations per 760.30. Type CI cable is installed for fire survivability and application of combustible paint may reduce this property of the cable.

79. The grocery store we are remodeling has a large transfer switch. Voltage is 480/277. Per NEC Table 110.26, the required working clearance from live parts under condition #2 is 42 inches. The existing clearances are only 40 inches.
1. Can they install plywood on the wall behind the equipment to move it out of the condition 2 and into condition 1 category?
2. The area of the transfer switch that only has 40 inches of clearance is the back of the enclosure which only supplies access to the main lugs. All serviceable-while-live components are accessed from the front where there is proper clearance. The only time they would access the lugs when complete would be with the main disconnect opened.
Answer - That’s not enough information to make a decision. See NEC 110.26(A).
1. Yes, this will change the conditions.
2. Some evaluation is required of the likelihood that the lugs may be examined while energized. For example, it is very common to do thermo graphic imagining of such connections while the system is under load. Since the lugs can only be accessed from the back, this type of testing would have to be done from the back with the cover removed. The proper working space would then be required.

80. My question pertains to a residential permanent swimming pool installation, involving NEC 680.21 (5) Cord and Plug Connections. The statement in this section that says pool-associated motors shall be permitted to employ cord and plug connections. Does this allow to choose to hard wire the motor? There is a motor rated snap switch for disconnecting means.
Answer - Yes. Any of the wiring methods mentioned in 680.21(A)(1) could be used for the entire installation. Section 680.21(A)(5) acts as an exception to 680.21(A)(1). So cords would be an option only if installed to meet all of the conditions in 680.21(A)(5). The HP rated snap switch would be permitted as the disconnect because it is one of the types of motor disconnecting means listed in 430.109.

81. There seems to be some confusion relating Article 250.122 (F) to Article 250.122 (B). I think that Article 250.122 (B) trumps Article 250.122 (F) in situations where current carrying conductors are increased in size to compensate for voltage drop or other reasons.
- Using the example provided in the 2008 NEC Handbook:
Ampacity of the Feeder: 250 Amps
Conductors proposed: Parallel 250 KCMil in separate raceways.
Standard Conductor Size @ 75 C: is 1- 250 KCMil Copper for a 250 Amp Feeder.
500,000 KCM/ 250,000 = Ratio of 2
Normally a # 4 Eq. Ground would be required. Per Chapter 9 Table 8, a number 4 AWG conductor has a Circular Mil of 41740.
41740 X 2 = 83690 CM
Per Chapter 9 Table 8, a 1AWG conductor ( 83690 CM) Equipment Grounding Conductors would be required in each raceway.
Answer - The example is correct. NEC 250.122(B) applies to circuits where the conductors are run in parallel. The equipment grounding conductor(s) are required to be increased in size proportionate to the increase in size of the ungrounded conductors.

82. Does NEC 520.6 mean that the derating requirements of 310.15(B)(2)(a) do not apply to conduit fill in theaters? The conductors all originate from a dimming rack in 10AWG THHN and are not all on at same time. They are dimmed to a level below full bright. Typically we run 30 circuits with separate neutrals in the same conduit to connector strips.
Answer - No, it does not. NEC 520.6 is telling us to use Table 1 in Chapter 9 when calculating conduit fill. However ,the ampacity adjustment requirements in Table 310.15(B)(2)(a) would still apply. The example you give would allow you to use that 10 AWG on a 20-ampere circuit where it is not supplying a multi-outlet branch circuit supplying receptacles for cord and plug connected portable loads. See 240.4(B)(1).
Table 310.16 indicates #10 THHN is rated at 40-amperes at 90 degrees C, which (although you cannot typically size the overcurrent device to the 90 degree C) you can use it for derating purposes. Table 310.15(B)(2)(a) requires derating to 45 percent for 21 thru 30 conductors in a raceway. 40X.45 = 8 amperes. 240.4(B)(1) allows you to use the next standard size overcurrent device, which would be a 20-ampere device.
Section 520.27 addresses feeders to stage switchboards and (B) indicates that the neutral conductor would not need to be considered for derating purposes if it is part of a feeder supplying a solid state sine wave 3-phase 4-wire dimming system only.
Section 310.15(B)(4)(a) indicates a neutral conductor that carries the unbalanced load of other conductors of the circuit does not need to be counted for derating purposes. This would be a multi-wire branch circuit such as a 3-wire circuit from a single phase system or a 4-wire circuit from a 3-phase Y system only.
Keep in mind 310.15(B)(4)((c) indicates that where a 4-wire 3-phase Y circuit supplies nonlinear loads or electronic equipment, such as HID lighting, there may be harmonic currents present and the neutral conductor is required to be counted as a current carrying conductor.
You indicate you have a neutral conductor for each hot conductor. I assume these are your branch circuits to the stage lighting, not the feeders referred to in 520.27. This would require that unless you meet one of the conditions in 310.15(B)(4), which it appears you do not, you are required to count all neutrals as current carrying and they would have to be considered for derating purposes.

83. For code article 445.13, I think the breaker in the generator is the first overcurrent device. Therefore, the line side conductors to the breaker must be 115 percent of nameplate rating not the load side. Do you agree?
Answer - In principal. NEC Section 445.12(A) requires overcurrent protection for the generator. It does not require a circuit breaker to be used. If a circuit breaker is utilized to protect the generator, the conductors on the load side of the breaker(s) are considered feeder conductors. Feeder conductors and feeder overcurrent protection devices are sized per Article 215, not 445.

84. I have a client who produces display cases for phone stores. He needs to install a powered free-standing display. Power will be supplied from a ceiling receptacle (installed in a drop ceiling). Can we install a 2 inch chase through the center of the kiosk, stopping it 6 inches from the ceiling? We would run a UL listed 15-foot power strip cord from the base, up thru the 2-inch chase and stub it out the side to plug into the ceiling receptacle. We would install grommets in the chase for cord protection and a round ball strain relief in the top of the pole, so the cord end doesn’t fall into the chase.
Answer - That would not be code compliant. NEC 400.8(6) does not allow flexible cord to be installed in a raceway accept for protection from damage in industrial establishments. You could use the cord as a pendant, and cord and plug connect at the ceiling receptacle. However, it could not be installed concealed in a chase.

85. We have been getting more calls on wind and solar generation and how to hook them into the utility. Is there person who would need to inspect these as they are not always covered under the new residential inspection requirement?
Answer - They must comply with NEC Art. 690 for PV systems and Art. 705 for Interconnected Electric Power Production Sources. The International Association of Electrical Inspector magazine has carried many fine articles over last few years on PV systems by John Wiles. You could check their web site at www.iaei.org for archived articles. Wiles also had some information free of charge at http://www.mnsu.edu/-tdi/photovoltaics/codes-stds/codes-stds. At this time there is no requirement for inspections at other than new one- and two-family homes, or other installations if required by the local municipality, or if the utility requires inspection of services before energizing.

86. For cross ventilated barns, what is your opinion on how often we are going to have to install expansion sleeves? We have been putting them in every row and spacing them at about 40 feet on 3/4-inch PVC conduit. These cross vent barns no longer see the extreme temperatures that the normal traditional barns are subject to. The low temp in there should be at 35 to 40 degrees and the high temperature should be maybe 90 degrees.
Answer - Expansion sleeves are required per NEC 352.44. You need to install an expansion joint when you have more then 1/4-inch expansion or contraction. Take a look at Table 352.44. For a 55-degree temperature change, they indicate a change of 2.23-inch per 100 feet. If we divide 2.23 by 100 = .0225-inch per foot. 40 feet X .0225 = .9-inch for the 40-foot run. You should be good if the expansion joint will take up that much. Let’s try 20 feet X .0225 = .45-inch. This tells me if you have a 20-foot straight run between two boxes you would also need an expansion joint.

87. I’m wiring a new pallet heat treater. The nameplate information indicates that it requires a 200-amp, 480 -volt, and 3-phase supply. We amp-probed it and it draws 162 amps. I was asked to take a look at the control panel which has three zones of electric heat, each drawing 52.5 amps and separately fused at 60 amps. Must we use NEC 424.22(B) and tell the customer that they need to subdivide the heating circuits to be 48 amps or less?
Answer - NEC Article 424 does not apply. The scope in 424.1 indicates the article does not apply to process heating equipment, which I assume this is. Hopefully this is a piece of listed equipment and as such all of the calculations would have been done. You can supply it with the circuit rating indicated by the manufacturer.

88. In an existing dwelling, a feeder panel is located in a clothes closet. The electrician wired a new heater in this dwelling and fed it from the existing feeder panel located in the clothes closet. They installed a 2-pole 20-ampere breaker and ran 112/2 NM to the heater. Is this code compliant?
Answer - No. You indicated the original installation might be 40 or 50 years old. I checked the 1944 state Electrical Code. Order 13-2435 indicates “Overcurrent devices shall be located where they will be: C. Not in the vicinity of easily ignitable material.” If this is the case, the panel is not a legal installation. Comm 16.003-(3) does not apply. The panel must be moved to a location that complies with the current electrical code since the requirement has essentially remained the same. An alternative would be to remove the clothing.

89. Let’s say we have various types of patient care areas. We are installing new fire alarm system in the units. The only devices in these areas will be horn / strobe that are mounted 6 feet 8 inches above floor and detectors which are ceiling mounted. We also are pulling cat 5 cabling for computer & possibly phone. Do I need to install these systems in conduit ?
Answer - Not for PLFA systems. Per NEC 517.80, the cables do not have to be run in a raceway unless other conditions are present. Exposure to physical damage is one condition that would prompt additional protection. If the cables are run within the walls and above the ceilings in a code- complaint manner, damage is not likely.

90. We have a large electrical room. There are two required exit doors. We bid it using “panic hardware” on the doors. During the value engineering stage, lever handles were substituted. Is this OK?
Answer - No. To comply with NFPA 72E and OSHA’s application of NFPA 101 the required personnel door/s shall be non-latching (hinged only) or shall have panic bar type latch release hardware installed. NEC Section 110.26(C)(3) apples to personnel doors that are located less than 25 feet from the nearest edge of the working space and used as a required exit from electrical rooms containing “large equipment.” Large equipment is defined in 110.26(C)(2) as equipment rated 1200 amperes or more and over 6 feet wide. The requirement for the personnel doors used as exits from such rooms was extensively revised in the 2005 edition of the NEC. The requirements for door hardware were specified as “panic bars, pressure plates, or other devices that are normally latched but open under simple pressure.”

91. Are the exhaust fans that HVAC installs to vent the repair area of major repair garage required to be listed for use in this environment? What should I look for in the blades to make them suitable for this use?
Answer - The term is “approved” for the environment. It may involve more than the type of blade used. See NEC 500.8(A) and (B). While the electrical code does require the electrical wiring to be an approved system for a classified area it does not address other equipment. The fan manufacturers do produce fans that are meant to exhaust atmospheres that would be considered hazardous and this type of equipment should be installed. While the code does not specifically require them to be listed, this would certainly be one of the requirements you should consider. UL 705 is a standard used for approval of fans located in a hazardous location. You can also check this web address for more information of other standards used by some manufacturers: www.greenheck.com/library/articles/40. Any of the fans that would be exhausting air from the classified areas would need to be approved for that use. This would include any areas that are not completely cut off from the classified area as described in 511.3. 511.3(E)(1) may allow the adjacent area to be unclassified if it meets the requirements of ventilation of four air changes per hour, or positive air pressure design of the space as noted.
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