Page 776 - 2018_IRC

POWER AND LIGHTING DISTRIBUTION

TABLE E3907.9.1(2) [Table 312.6(A)] E3908.3 Specific equipment fastened in place (fixed) or
MINIMUM WIRE-BENDING SPACE AT TERMINALS connected by permanent wiring methods. Exposed, nor-
AND MINIMUM WIDTH OF WIRING GUTTERS (see Note 1) mally noncurrent-carrying metal parts of the following equip-
COMPACT WIRES PER TERMINAL
STRANDED One Two ment and enclosures shall be connected to an equipment
ALL OTHER AA-8000 grounding conductor:
CONDUCTORS ALUMINUM 1. Luminaires as provided in Chapter 40. [250.112(J)]
ALLOY
CONDUCTORS inches mm inches mm
(see Note 2) 2. Motor-operated water pumps, including submersible
Not Not types.Where a submersible pump is used in a metal well
14-10 12-8 — — casing, the well casing shall be connected to the pump
specified specified
circuit equipment grounding conductor. [250.112(L)]
1
8-6 6-4 1 / 2 38.1 — —
4-3 2-1 2 50.8 — — E3908.4 Effective ground-fault current path. Electrical
equipment and wiring and other electrically conductive mate-
2 1 / 0 2 1 / 63.5 — —
2 rial likely to become energized shall be installed in a manner
1 2 / 0 3 7 6 . 2 — — that creates a low-impedance circuit facilitating the operation
1
1/0-2/0 3/0-4/0 3 / 2 88.9 5 127 of the overcurrent device or ground detector for high-imped-
3/0-4/0 250-300 4 102 6 152 ance grounded systems. Such circuit shall be capable of safely
carrying the maximum ground-fault current likely to be
250 350 4 / 2 114 6 152 imposed on it from any point on the wiring system where a
1
300-350 400-500 5 127 8 203 ground fault might occur to the electrical supply source.
400-500 600-750 6 152 8 203 [250.(A)(5)]
600-700 800-1000 8 203 10 254 E3908.5 Earth as a ground-fault current path. The earth
750-900 — 8 203 12 305 shall not be considered as an effective ground-fault current
path. [250.4(A)(5)]
1000-1250 — 10 254 — —
1500-2000 — 12 305 — — E3908.6 Load-side grounded conductor neutral. A
grounded conductor shall not be connected to normally non-
Notes: current-carrying metal parts of equipment, to equipment
1. Bending space at terminals shall be measured in a straight line from the grounding conductor(s), or be reconnected to ground on the
end of the lug or wire connector (in the direction that the wire leaves the load side of the service disconnecting means. [250.24(A)(5)]
terminal) to the wall, barrier, or obstruction.
2. This column shall be permitted to be used to determine the minimum wire- E3908.7 Load-side equipment. A grounded circuit conduc-
bending space for compact stranded aluminum conductors in sizes up to tor shall not be used for grounding noncurrent-carrying metal
1000 kcmil and manufactured using AA-8000 series electrical grade parts of equipment on the load side of the service disconnect-
aluminum alloy conductor material in accordance with 310.106(B). The
minimum width of the wire gutter space shall be determined using the all ing means. [250.142(B)]
other conductors value in this table.
E3908.8 Types of equipment grounding conductors. The
equipment grounding conductor run with or enclosing the cir-
2. Metal components that are installed in an under- cuit conductors shall be one or more or a combination of the
ground installation of rigid nonmetallic conduit and following:
are isolated from possible contact by a minimum
cover of 18 inches (457 mm) to any part of the metal 1. A copper, aluminum or copper-clad conductor. This
components or that are isolated from possible con- conductor shall be solid or stranded; insulated, covered
tact by encasement in not less than 2 inches (51 mm) or bare; and in the form of a wire or a busbar of any
of concrete. (250.86 Exception No. 3) shape. [250.118(1)]
E3908.2 Equipment fastened in place or connected by 2. Rigid metal conduit. [250.118(2)]
permanent wiring methods (fixed). Exposed, normally non- 3. Intermediate metal conduit. [250.118(3)]
current-carrying metal parts of fixed equipment supplied by
or enclosing conductors or components that are likely to 4. Electrical metallic tubing. [250.118(4)]
become energized shall be connected to the equipment 5. Armor of Type AC cable in accordance with Section
grounding conductor where any of the following conditions E3908.4. [250.118(8)]
apply: 6. Type MC cable that provides an effective ground-fault
1. Where within 8 feet (2438 mm) vertically or 5 feet current path in accordance with one or more of the fol-
(1524 mm) horizontally of earth or grounded metal lowing:
objects and subject to contact by persons; 6.1. It contains an insulated or uninsulated equip-
2. Where located in a wet or damp location and not iso- ment grounding conductor in compliance with
lated; or Item 1 of this section.
3. Where in electrical contact with metal. (250.110) 6.2. The combined metallic sheath and uninsulated
equipment grounding/bonding conductor of

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