Page 743 - 2018_IRC

BRANCH CIRCUIT AND FEEDER REQUIREMENTS

E3705.3 Adjustment factor for conductor proximity. selected and coordinated to not exceed the lowest tempera-
Where the number of current-carrying conductors in a race- ture rating of any connected termination, conductor or device.
way or cable exceeds three, or where single conductors or Conductors with temperature ratings higher than specified for
multiconductor cables are stacked or bundled for distances terminations shall be permitted to be used for ampacity
greater than 24 inches (610 mm) without maintaining spacing adjustment, correction, or both. Except where the equipment
and are not installed in raceways, the allowable ampacity of is marked otherwise, conductor ampacities used in determin-
each conductor shall be reduced as shown in Table E3705.3. ing equipment termination provisions shall be based on Table
[310.15(B)(3)] E3705.1. [110.14(C)]
Exceptions: E3705.4.1 Conductors rated 60°C. Except where the
equipment is marked otherwise, termination provisions of
1. Adjustment factors shall not apply to conductors in
raceways having a length not exceeding 24 inches equipment for circuits rated 100 amperes or less, or
(610 mm). [310.15(B)(3)(2)] marked for 14 AWG through 1 AWG conductors, shall be
used only for one of the following:
2. Adjustment factors shall not apply to underground
conductors entering or leaving an outdoor trench if 1. Conductors rated 60°C (140°F);
those conductors have physical protection in the 2. Conductors with higher temperature ratings, pro-
form of rigid metal conduit, intermediate metal con- vided that the ampacity of such conductors is deter-
duit, or rigid nonmetallic conduit having a length not mined based on the 60°C (140°F) ampacity of the
exceeding 10 feet (3048 mm) and the number of conductor size used;
conductors does not exceed four.[310.15(B)(3)(3)]
3. Conductors with higher temperature ratings where
3. Adjustment factors shall not apply to type AC cable the equipment is listed and identified for use with
or to type MC cable without an overall outer jacket such conductors; or
meeting all of the following conditions:
4. For motors marked with design letters B, C, or D con-
3.1. Each cable has not more than three current- ductors having an insulation rating of 75°C (167°F)
carrying conductors. or higher shall be permitted to be used provided that
the ampacity of such conductors does not exceed the
3.2. The conductors are 12 AWG copper.
75°C (167°F) ampacity. [110.14(C)(1)(a)]
3.3. Not more than 20 current-carrying conduc-
tors are bundled, stacked or supported on bri- E3705.4.2 Conductors rated 75°C. Termination provi-
dle rings. [310.15(B)(3)(4)] sions of equipment for circuits rated over 100 amperes, or
marked for conductors larger than 1 AWG, shall be used
4. An adjustment factor of 60 percent shall be applied only for:
to Type AC cable and Type MC cable where all of
the following conditions apply: 1. Conductors rated 75°C (167°F).
2. Conductors with higher temperature ratings provided
4.1. The cables do not have an overall outer
jacket. that the ampacity of such conductors does not exceed
the 75°C (167°F) ampacity of the conductor size used,
4.2. The number of current-carrying conductors or provided that the equipment is listed and identified
exceeds 20. for use with such conductors. [110.14(C)(1)(b)]
4.3. The cables are stacked or bundled longer E3705.4.3 Separately installed pressure connectors.
than 24 inches (607 mm) without spacing Separately installed pressure connectors shall be used with
being maintained. [310.15(B)(3)(4) Excep- conductors at the ampacities not exceeding the ampacity at
tion] the listed and identified temperature rating of the connec-
tor. [110.14(C)(2)]
TABLE E3705.3 [Table 310.15(B)(3)(a)]
CONDUCTOR PROXIMITY ADJUSTMENT FACTORS E3705.4.4 Conductors of Type NM cable. Conductors in
NUMBER OF CURRENT-CARRYING PERCENT OF VALUES IN NM cable assemblies shall be rated at 90°C (194°F). Types
CONDUCTORS IN CABLE OR RACEWAY TABLE E3705.1 NM, NMC, and NMS cable identified by the markings NM-
4-6 80 B, NMC-B, and NMS-B meet this requirement. The allow-
7-9 70 able ampacity of Types NM, NMC, and NMS cable shall
not exceed that of 60°C (140°F) rated conductors and shall
10-20 50
comply with Section E3705.1 and Table E3705.5.3. The
21-30 45 90°C (194°F) rating shall be permitted to be used for
31-40 40 ampacity adjustment and calculations provided that the
41 and above 35 final corrected or adjusted ampacity does not exceed that
for a 60°C (140°F) rated conductor. Where more than two
NM cables containing two or more current-carrying con-
E3705.4 Temperature limitations. The temperature rating ductors are installed, without maintaining spacing between
associated with the ampacity of a conductor shall be so the cables, through the same opening in wood framing that

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