This article was posted 06/20/2006 and is most likely outdated.

NEC Questions and Answers June (Part 3)
 

 
Topic - NEC Questions
Subject - NEC Questions and Answers June (Part 3)

June 20, 2006  

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NEC Questions June Part 3

 

By Mike Holt for EC&M Magazine

 

Q1. What are the GFCI protection requirements for a receptacle supplying a water fountain?

A1. GFCI protection is not required by the NEC for the outlets supplying drinking water fountain equipment.

 

Q2. Am I required to bond around reducing washers?

A2. Surprisingly enough, the answer is no you don’t have to bond around reducing washers, if the reducing washers are listed. According to the UL White Book, category QCRV, “Metal reducing washers are considered suitable for grounding for use in circuits over and under 250V and where installed in accordance with the National Electrical Code.’’

 

Q3. Does an above the range combination microwave/hood fan require a dedicated circuit if its cord-and-plug connected?

A3. Yes [422.16(B)(4)(5)], and be sure to comply with the following as well [422.16(B)(4)]:

(1) The flexible cord must terminate with a grounding-type attachment plug.

(2) The length of the cord must not be less than 18 in. or longer than 36 in.

(3) The range hood receptacle must be located to avoid physical damage to the flexible cord.

(4) The range hood receptacle must be accessible.

 

Q4. What are the rules on mixing emergency circuits in the same raceway or enclosure with nonemergency circuits?

A4. To ensure that a fault on the normal wiring circuits will not affect the performance of emergency wiring or equipment, all wiring from an emergency source, or emergency source distribution overcurrent protection, to emergency loads must be kept entirely independent of all other wiring and equipment, except [700.9(B)]:

(1) Wiring in transfer equipment enclosures.

(2) Exit or emergency luminaires supplied from two sources of power.

(3) A common junction box attached to luminaires supplied from two sources of power.

 

Q5. Does the NEC require safety chains on high bay lighting fixtures?

A5. No, this is not an NEC requirement.

 

Q6. Can AFCI type receptacles be used to meet the requirements of the NEC?

A6. Yes if the AFCI is located within 6 ft of the branch-circuit overcurrent device, as measured along the branch-circuit conductors, and if the circuit conductors are installed in a metal raceway or a cable with a metallic sheath [210.12(B) Exception]. But because of the limited demand, AFCI protection devices of the receptacle type are not made. So this is a moot point.

 

Q7. Can I use 12-3 NM cable to wire the bathroom GFCI’s and the laundry circuit in a dwelling?

A7. Sure, if you use a GFCI receptacle for the first outlet for the bathroom receptacle circuit. Just remember that continuity of the grounded (neutral) conductor of a multiwire branch circuit must not be interrupted by the removal of a wiring device. Therefore, the grounded (neutral) conductors must be spliced together, and a pigtail must be provided for the wiring device [300.13(B)].

 

Q8. Is Liquidtight Flexible Metal Conduit permitted under the raised floor of a computer room? If yes, must it be secured?

A8. It depends on what you mean by a computer room. If you are talking about an Information Technology Equipment (ITE) room as per 645.4, the answer is yes, LFMC can be used if secured, [645.5(D)(2)].

 

Now if the computer room does not qualify as an ITE room, and the raised floor is not used for environmental air, the answer is still yes if secured in accordance with 300.11. But, if the computer room does not qualify as an ITE room, and the raised floor is used as an environmental air space (for air-conditioning) then LFMC can’t be used at all [300.22(B)(1)].

 

Q9. Can power conductors for an intercom system be mixed in the same raceway with the audio output conductors?

Q9. No. 640.9(C) requires that audio output circuits utilizing Class 2 or Class 3 wiring methods not be placed in any enclosure, raceway, or cable with conductors of electric light, power, Class 1, and nonpower-limited fire alarm circuits [725.55].

 

Q10. What type of wiring method must I use for 24V lighting supplied by a 1.5 kVA (1,500 VA) transformer?

A10. Low voltage lighting of less than 100 VA can be wired in accordance with the requirements of a Class 2 circuit [725.52]. However, low-voltage lighting over 100 VA is no longer considered a Class 2 circuit and must be wired with a Chapter 3 wiring method (pipe, wire, and/or cable) in accordance with 300.3.

 
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Comments

  • Question 5 should be answered as follows:

    Chains/guy wire is required according the the UBC/IBC depending on the seismic areas the installation jis taking place. Although we adhere to the NEC, we must also be aware of the other code requirements to keep us out of trouble and wasting time and money.

    Thanks,

    Jerry E. So. Ca.

    Jerry E.
    Reply to this comment

    • Reply from: foerdoneRep   
    walsitemittee     blospersolurb
    Reply to foerdoneRep

  • On 6/20/06 Code Q&A, I believe you replied with incomplete information. Tthe question was

    Q8. Is Liquidtight Flexible Metal Conduit permitted under the raised floor of a computer room? If yes, must it be secured?

    ... and you replied with 2 answers

    A8. It depends on what you mean by a computer room. If you are talking about an Information Technology Equipment (ITE) room as per 645.4, the answer is yes, LFMC can be used if secured, [645.5(D)(2)]. Now if the computer room does not qualify as an ITE room, and the raised floor is not used for environmental air, the answer is still yes if secured in accordance with 300.11. But, if the computer room does not qualify as an ITE room, and the raised floor is used as an environmental air space (for air-conditioning) then LFMC can’t be used at all [300.22(B)(1)].

    You should have provided a 3rd answer.

    If the cables (in LFM/C) are power cables, communications cables, or interconnecting cables that are listed as part of, or for, IT equipment, then they do NOT have to be secured in place. This is the most important reason for a user to have a space designated as an IT space under Article 645. See 645.5(E)

    Steve McCluer
    Reply to this comment

  • Mike, I realize that you make a living by teaching, discussing, and working with the NEC.

    I appreciate your giving away SO MUCH to the trade in newsletters, quizes, Q & A , and other ways. Thanks.

    No, make that THANKS!

    Lynn

    Lynn Adams
    Reply to this comment

  • Q3. Does an above the range combination microwave/hood fan require a dedicated circuit if its cord-and-plug connected?

    A3. Yes [422.16(B)(4)(5)], and be sure to comply with the following as well [422.16(B)(4)]:

    (1) The flexible cord must terminate with a grounding-type attachment plug.

    (2) The length of the cord must not be less than 18 in. or longer than 36 in.

    (3) The range hood receptacle must be located to avoid physical damage to the flexible cord.

    (4) The range hood receptacle must be accessible.

    Am I mistaken I thought that 422.16 (B) pertained to disposals. If this is the wrong answer please provide the correct one. We are constantly see Vent hoods removed and Home Owners installing a built in Microwave on this typically shared 15 amp service. This is causing a lot of new problems for new home owners.

    Thank you for your time.

    John K. Erickson
    Reply to this comment

  • The Quiz: Q7. Can I use 12-3 NM cable to wire the bathroom GFCI’s and the laundry circuit in a dwelling? A7. Sure, if you use a GFCI receptacle for the first outlet for the bathroom receptacle circuit. Just remember that continuity of the grounded (neutral) conductor of a multiwire branch circuit must not be interrupted by the removal of a wiring device. Therefore, the grounded (neutral) conductors must be spliced together, and a pigtail must be provided for the wiring device [300.13(B)].

    The Comment: Except that the neutral conductor at the GFCI should be a pass-through, not a pigtail, if you intend to use this GFCI to protect receptacles down stream.

    Cheers,

    Ken Lillemo
    Reply to this comment

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