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قديم 03-01-2016, 04:27 PM
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تاريخ التسجيل: Nov 2010
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c**sultant Mike Holt

Q. What are the receptacle spacing requirements for a dwelling unit, in other than kitchens or bathrooms?
A. Secti** 210.52 provides requirements for 15A and 20A, 125V receptacle outlets in dwelling units. The receptacles required by this secti** are in additi** to any receptacle that is:
1. Part of a luminaire or appliance,
2. C**trolled by a wall switch in accordance with 210.70(A)(1), Ex 1.
3. Located ****** cabinets or cupboards, or
4. Located **** 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, recreati** room, and similar room or area in accordance with (1), (2), and (3):
According to 210.52(A)(1), a receptacle outlet must be installed so that no point al**g the floor line of any wall is **** than 6 ft, measured horiz**tally al**g the floor line, from a receptacle outlet, as shown in the Figure. The purpose of this rule is to ensure that a general-purpose receptacle is c**veniently located to reduce the chance that an extensi** cord will be used.
Wall space is defined as:
1. Any space 2 ft or **** in width, unbroken al**g 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 are located **** than 18 in. from the wall. 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).
Ex 1: The 20A, 120V small-appliance branch circuit can be used to supply a receptacle for an electric clock.
Ex 2: A receptacle can be c**nected to the small-appliance branch circuit to supply a gas-fired range, oven, or counter-mounted cooking unit.
A range hood or above-the-range microwave listed as a range hood must be supplied by an individual branch circuit [422.16(B)(4)(5)].
Q. What are the basic working space requirements for a dwelling unit?
A. The same rules apply to dwelling units as for any other occupancy. According to 110.26, access and working space must be provided about all electrical equipment, for the purpose of safe operati** and maintenance of equipment. Equipment that may need examinati**, adjustment, servicing,
or maintenance while energized must have working space provided in accordance with (A)(1), (A)(2), and (A)(3). The phrase “while energized” is the root of many debates. As always, check
with the AHJ to see what equipment he or she believes needs a clear working space.
The depth of the working space, which is measured from the enclosure fr**t, must not be less than the distances c**tained in Table 110.26(A)(1). For dwelling units, the minimum depth required from this table is 3 ft, because the voltage to ground is not **** than 150V in dwelling units.
The width of the working space must be a minimum of 30 in. but in no case less than the width of the equipment. The width of the working space can be measured from left-to-right, from right-to-left, or simply centered ** the equipment — and the working space can overlap the working space for other electrical equipment. In all cases, the working space must be of sufficient width, depth, and height to permit all equipment doors to open 90°.
The height of the working space (i.e., headroom) in fr**t of equipment must not be less than 6½ ft, measured from the grade, floor, platform, or the equipment height, whichever is greater. Equipment such as raceways, cables, wireways, cabinets, panels, and so ** can be located above or below electrical equipment, but must not extend **** than 6 in. into the equipment’s working space.
Ex 1: The minimum headroom requirement doesn’t apply to service equipment or panelboards rated 200A or less located in an existing dwelling unit.
Q. Are anti-short bushings required for both Type AC and Type MC cable terminati**s?
A. Type AC cable must terminate in boxes or fittings specifically listed for Type AC cable to protect the c**ductors from abrasi** [300.15 and 320.40]. An insulating anti-short bushing, sometimes called a “redhead,” must be installed at all Type AC cable terminati**s. The terminati** fitting must permit the visual inspecti** of the anti-short bushing **ce the cable has been installed [320.40].
The following are some other items to keep in mind when working with Type AC cable:
· The internal aluminum b**ding strip ****** the cable serves no electrical purpose **ce outside the cable and can be cut off, but many electricians use it to secure the anti-short bushing to the cable (see 320.108).
· C**ductors 4 AWG and larger that enter an enclosure must be protected from abrasi** during and after installati** by a fitting that provides a smooth, rounded, insulating surface, such as an insulating bushing unless the design of the box, fitting, or enclosure provides equivalent protecti** in accordance with 300.4(G).
Fittings used to secure Type MC cable to boxes or other enclosures must be listed and identified for such use [300.15 and 330.40].
· The NEC does not require anti-short bushings (redheads) at the terminati** of Type MC cable, but if they are supplied it is c**sidered by many to be a good practice to use them.
· C**ductors 4 AWG and larger that enter an enclosure must be protected from abrasi** during and after installati** by a fitting that provides a smooth, rounded, insulating surface, such as an insulating bushing unless the design of the box, fitting, or enclosure provides equivalent protecti** in accordance with 300.4(G).





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