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Stumped by the Code?

Sep 9, 2009 11:59 AM, By Mike Holt, NEC Consultant

Your most pressing National Electrical Code (NEC) questions answered. All questions and answers are based on the 2008 NEC.

Q. Do we have to install a receptacle behind the swing of a door in a bedroom of a dwelling unit, even if the wall is only 2 ft 6 in. wide?

The Code is very specific on placement of receptacle outlets in dwelling units.

A. Yes. The requirements are contained in 210.52(A), which reads: A receptacle outlet must be installed in every kitchen, family room, dining room, living room, sunroom, parlor, library, den, bedroom, recreation room, and similar room or area in accordance with (1), (2), and (3):

(1) Receptacle placement. A receptacle outlet must be installed so that no point along the wall space is more than 6 ft, measured horizontally along the floor line, from a receptacle outlet. The purpose of this rule is to ensure that a general-purpose receptacle is conveniently located to reduce the chance that an extension cord will be used.

(2) Definition of wall space.

• (1) Any space 2 ft or more in width, unbroken along the floor line by doorways, fireplaces, and similar openings.

• (2) The space occupied by fixed panels in exterior walls.

• (3) The space occupied by fixed room dividers, such as freestanding bar-type counters or guard rails.

(3) Floor receptacle outlets. Floor receptacle outlets aren’t counted as the required receptacle wall outlet if they’re located more than 18 in. from the wall.

Q. We paralleled two sets of 500kcmil phase conductors on the secondary side of a customer-owned transformer. How do I size the equipment grounding conductor for each raceway, if the raceway is flexible metal conduit?

A. An equipment bonding jumper must be run to the secondary system disconnecting means. Where the secondary equipment grounding conductor is of the wire type, it must be sized in accordance with Table 250.66, based on the area of the largest ungrounded secondary conductor in each raceway or cable [250.30(A)(2) and 250.102(C)].

Example: What size equipment bonding jumper is required for each flexible metal conduit containing 500kcmil secondary conductors? As per Table 250.66, the answer is 1/0 AWG.

Q. We cut our wire too short in a few outlet boxes so I spliced on a couple inches of conductor so that I had the required 6 in. of free conductor at each location. The inspector says the free conductor must be "unspliced." Is he right?

A. No. He is correct that the NEC requires at least 6 in. of free conductor be available from the point in the box where the conductors enter the enclosure [300.14]. However, nowhere in this rule does it require that the free length of conductor be unspliced.

Q. Does the Code tell us the largest size conductor we can splice with a twist-on type wire connector?

A. Not really. The closest thing you are going to find is 110.14, which tells us that conductor splicing devices must be identified for the conductor material, and they must be properly installed. The answer to how many conductors and what size can be installed in a wire connector is simply "whatever the connector is listed for."

Q. If we have receptacles located within 20 ft of an outside swimming pool, but the receptacles are located indoors, do we have to provide GFCI protection for them?

A. No. GFCI protection is only required for 15A and 20A, 125V receptacles located within 20 ft from the inside walls of a permanently installed pool, outdoor spa, or outdoor hot tub [680.22(A)(4)]. The distance shall be the shortest path the supply cord of an appliance connected to the receptacle would follow without piercing a floor, wall, ceiling, doorway with hinged or sliding door, window opening, or other effective permanent barrier [680.22(A)(5)].

Q. Is there is limit on how far the bathroom receptacle must be from a shower or bathtub?

A. No, but receptacles must not be installed within or directly over a bathtub or shower stall [406.8(C].

Q. We installed an equipment grounding conductor in our metal raceways even though the Code doesn’t require us to. Does the equipment grounding conductor have to be properly sized, even though it doesn’t have to be there in the first place?

A. Yes, there are no exceptions to the rules found in Art. 250 that would allow you to undersize the equipment grounding conductor. Equipment grounding conductors of the wire type must be sized not smaller than shown in Table 250.122 based on the rating of the circuit overcurrent device; however, the circuit equipment grounding conductor is not required to be larger than the circuit conductors [250.122(A)].