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NEC Questions and Answers - Based on 2011 NEC
July 2013
By Mike Holt for EC&M Magazine
Here’s the follow up to yesterday’s newsletter. This includes all of the answers to the questions sent, so you can see how you did.
Q1. Section 210.60(B) allows the placement of receptacle outlets to be less than required in a dwelling unit to accommodate permanent furniture placement. Does this apply to a guest room with permanent provisions for cooking (also viewed as a dwelling unit)?
A1. No. Guest rooms or guest suites in hotels, motels, and sleeping rooms in dormitories and similar occupancies, must have receptacle outlets installed in accordance with all the requirements for a dwelling unit as described in 210.52(A) and 210.52(D).
Guest rooms with permanent provisions for living, sleeping, cooking, and sanitation must have receptacles installed in accordance with the dwelling unit requirements of 210.52 [210.60(A)]. The allowances of 210.60(B) apply only to guest rooms, not to dwelling units.
Q2. What is the requirement for the location of receptacle outlets in dwelling bathrooms?
A2. In dwelling units, not less than one 15A or 20A, 125V receptacle outlet must be installed within 3 ft from the outside edge of each bathroom basin [210.52(D)]. The receptacle outlet must be located on a wall or partition adjacent to the basin counter surface, or on the side or face of the basin cabinet not more than 12 in. below the countertop.
Receptacle outlet assemblies listed for the application can be installed in countertops.
Informational Note: Receptacles must not be installed in a face-up position in countertops or similar work surface areas in a dwelling unit [406.5(E)].
Author’s Comments:
• One receptacle outlet can be located between two basins to meet this requirement, but only if it’s located within 3 ft of the outside edge of each basin.
• The bathroom receptacles must be GFCI protected [210.8(A)(1)].
Q3. What are the clearance requirements for overhead conductors over a swimming pool or hot tub?
A3. Overhead power conductors must meet the clearance requirements contained in Table 680.8. The clearance is measured from the maximum water level.
Permanently installed pools, storable pools, outdoor spas, outdoor hot tubs, fountains, diving structures, observation stands, towers, or platforms must not be placed within the clearances from overhead conductors contained in the NEC, Table 680.8 [680.8(A)].
Author’s Comment: This rule doesn’t prohibit utility-owned overhead service-drop conductors from being installed over a permanently installed pool, storable pool, outdoor spa, outdoor hot tub, or fountain [90.2(B)(5)]. It does prohibit a permanently installed pool, storable pool, outdoor spa, outdoor hot tub, or fountain from being installed under an existing service drop that isn’t at least 22½ ft above the water.
In addition, permanently installed pools, storable pools, outdoor spas, outdoor hot tubs, fountains, diving structures, observation stands, towers or platforms must not be placed under or within 10 ft of overhead communications cables.
Q4. Are low-voltage lighting systems operating at 30V or less required to be listed?
A4. Low-voltage lighting systems operating at 30V or less must comply with 411.3(A) or (B):
- Be listed as a complete system, including the power supply and luminaires [411.3(A)].
- A lighting system assembled from the following listed parts is permitted [411.3(B)]:
(1) Low-voltage luminaires.
(2) Low-voltage luminaire power supply.
(3) Class 2 power supply.
(4) Low-voltage luminaire fitting.
(5) Cords that the luminaires and power supply are listed for use with.
(6) Cable, conductors in a raceway, or other fixed wiring method for the secondary circuit.
The luminaires, power supply, and luminaire fittings of an exposed bare conductor lighting system must be listed for use as part of the same identified lighting system.
Q5. What are acceptable wiring methods for low voltage (under 30V) lighting conductors?
A5. Section 411.5 contains the following wiring method requirements for low voltage secondary circuits:
- Secondary circuits aren’t permitted to be grounded.
- The secondary circuit must be insulated from the branch circuit by an isolating transformer.
- Exposed bare conductors and current-carrying parts must not be installed less than 7 ft above the finished floor, unless listed for a lower height.
- Exposed insulated secondary circuit conductors must be:
- Supplied by a Class 2 power source with Class 2 cable in accordance with Article 725.
- Installed at least 7 ft above the finished floor unless listed for a lower installation height.
- Installed in a Chapter 3 wiring method.
Q6. Are indoor installations of a spa or hot tub required to comply with the equipotential bonding requirements of 680.26(B)(2)?
A6. Not according to the exception to 680.43:
Electrical installations for an indoor spa or hot tub must comply with Parts I and II of Article 680, except as modified by this section. Indoor installations of spas or hot tubs can be connected by any of the wiring methods contained in Chapter 3 [680.43].
Ex 2: The equipotential bonding requirements for perimeter surfaces contained in 680.26(B)(2) don’t apply to a listed self-contained spa or hot tub installed above an indoor finished floor.
Note: there is also an NFPA Tentative Interim Amendment [TIA70-11-1] to 680.42(B) which provides the same type of exception for a listed self-contained spa or hot tub located outdoors. This is a change that takes place in the Code between Editions.
Q7. What is the Code rule regarding receptacle outlets placement in a dwelling unit?
A7. Section 210.52 provides requirements for 15A and 20A, 125V receptacle outlets. The receptacles required by this section are in addition to any receptacle that is [210.52]:
(1) Part of a luminaire or appliance,
(2) Controlled by a wall switch in accordance with 210.70(A)(1), Ex 1.
(3) Located within cabinets or cupboards, or
(4) Located more than 5½ ft above the floor.
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 210.52(A)(1), (2), and (3):
- A receptacle outlet must be installed so that no point along the floor line of any wall is more than 6 ft, measured horizontally along the floor line, from a receptacle outlet [210.52(A)(1)].
Author’s Comment: 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.
- Definition of Wall Space [210.52(A)(2)].
(1) Any space 2 ft or more in width, unbroken along the floor line by doorways and similar openings, fireplaces, and fixed cabinets.
(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.
Floor receptacle outlets aren’t counted as the required receptacle wall outlet if they’re located more than 18 in. from the wall [210.52(A)(3)].
(4) Countertop Receptacles. Receptacles installed for countertop surfaces as required by 210.52(C), can’t be used to meet the receptacle requirements for wall space as required by 210.52(A).
Q8. What is the Code rule regarding receptacle outlets placement in a dwelling unit kitchen?
A8. In kitchens, pantries, breakfast rooms, dining rooms, and similar areas of dwelling units, receptacle outlets for countertop spaces must be installed according to 210.52(C) (1) through (5) below:
A receptacle outlet must be installed for each kitchen and dining area countertop wall space 1 ft or wider, and receptacles must be placed so that no point along the countertop wall space is more than 2 ft, measured horizontally, from a receptacle outlet.
Ex: A receptacle outlet isn’t required on a wall directly behind a range, counter-mounted cooking unit, or sink, in accordance with Figure 210.52(C)(1) in the NEC.
Author’s Comment: If the countertop space behind a range or sink is larger than the dimensions noted in Figure 210.52(C)(1) of the NEC, then a GFCI-protected receptacle must be installed in that space. This is because, for all practical purposes, if there’s sufficient space for an appliance, an appliance will be placed there.
At least one receptacle outlet must be installed at each island countertop space with a long dimension of 2 ft or more, and a short dimension of 1 ft or more.
At least one receptacle outlet must be installed at each peninsular countertop with a long dimension of 2 ft or more, and a short dimension of 1 ft or more, measured from the connecting edge.
Author’s Comment: The Code doesn’t require more than one receptacle outlet in an island or peninsular countertop space, regardless of the length of the countertop, unless the countertop is broken as described in 210.52(C)(4).
(4) When breaks occur in countertop spaces for rangetops, refrigerators, or sinks, each countertop space is considered as a separate countertop for determining receptacle placement.
If a range, counter-mounted cooking unit, or sink is installed in an island or peninsular countertop, and the depth of the counter behind the range, counter-mounted cooking unit, or sink is less than 12 in., the countertop space is considered to be two separate countertop spaces.
Author’s Comment: GFCI protection is required for all 15A and 20A, 125V receptacles that supply kitchen countertop surfaces [210.8(A)(6)].
(5) Receptacle outlets required by 210.52(C)(1) for the countertop space must be located on or above, but not more than 20 in. above, the countertop surface. Receptacle outlet assemblies listed for the application can be installed in countertops.
Informational Note: Receptacles must not be installed in a face-up position in countertops or similar work surface areas in a dwelling unit [406.5(E)].
Ex: The receptacle outlet for the countertop space can be installed below the countertop only for construction for the physically impaired or when wall space or a backsplash isn’t available, such as in an island or peninsular counter. Under these conditions, the required receptacle(s) must be located no more than 1 ft below the countertop surface and no more than 6 in. from the countertop edge, measured horizontally.
Receptacle outlets rendered not readily accessible by appliances fastened in place, located in an appliance garage, behind sinks, or rangetops [210.52(C)(1) Ex], or supplying appliances that occupy dedicated space don’t count as the required countertop receptacles.
Author’s Comment: An “appliance garage” is an enclosed area on the countertop where an appliance can be stored and hidden from view when not in use. If a receptacle is installed inside an appliance garage, it doesn’t count as a required countertop receptacle outlet.
For more NEC Practice, purchase Mike Holt's NEC Exam Practice Questions book based on the 2011 NEC.
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