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GENERAL REQUIREMENTS

SECTION E3406 TW, UF, USE, USE-2, XHHW or XHHW-2. Insulation types
ELECTRICAL CONDUCTORS AND CONNECTIONS shall be approved for the application. [310.10(B), (C), 310.104]
E3406.1 General. This section provides general require- E3406.6 Conductors in parallel. Circuit conductors that are
ments for conductors, connections and splices. These require- connected in parallel shall be limited to sizes 1/0 AWG and
ments do not apply to conductors that form an integral part of larger. Conductors in parallel shall: be of the same length; con-
equipment, such as motors, appliances and similar equip- sist of the same conductor material; be the same circular mil
ment, or to conductors specifically provided for elsewhere in area and have the same insulation type. Conductors in parallel
Chapters 34 through 43. (310.1) shall be terminated in the same manner. Where run in separate
E3406.2 Conductor material. Conductors used to conduct raceways or cables, the raceway or cables shall have the same
current shall be of copper or aluminum except as otherwise physical characteristics. Where conductors are in separate
provided in Chapters 34 through 43. Where the conductor raceways or cables, the same number of conductors shall be
material is not specified, the material and the sizes given in used in each raceway or cable. [310.10(H)]
these chapters shall apply to copper conductors. Where other E3406.7 Conductors of the same circuit. All conductors of
materials are used, the conductor sizes shall be changed the same circuit and, where used, the grounded conductor and
accordingly. (110.5) all equipment grounding conductors and bonding conductors
E3406.3 Minimum size of conductors. The minimum size of shall be contained within the same raceway, cable or cord.
conductors for feeders and branch circuits shall be 14 AWG [300.3(B)]
copper and 12 AWG aluminum. The minimum size of service E3406.8 Aluminum and copper connections. Terminals
conductors shall be as specified in Chapter 36. The minimum and splicing connectors shall be identified for the material of
size of Class 2 remote control, signaling and power-limited cir- the conductors joined. Conductors of dissimilar metals shall
cuits conductors shall be as specified in Chapter 43. not be joined in a terminal or splicing connector where physi-
[310.106(A)] cal contact occurs between dissimilar conductors such as cop-
E3406.4 Stranded conductors. Where installed in raceways, per and aluminum, copper and copper-clad aluminum, or
conductors 8 AWG and larger shall be stranded. A solid 8 aluminum and copper-clad aluminum, except where the
AWG conductor shall be permitted to be installed in a race- device is listed for the purpose and conditions of application.
way only to meet the requirements of Sections E3610.2 and Materials such as inhibitors and compounds shall be suitable
E4204. [310.106(C)] for the application and shall be of a type that will not
adversely affect the conductors, installation or equipment.
E3406.5 Individual conductor insulation. Except where oth- (110.14)
erwise permitted in Sections E3605.1 and E3908.9, and E4303,
current-carrying conductors shall be insulated. Insulated con- E3406.9 Fine stranded conductors. Connectors and termi-
ductors shall have insulation types identified as RHH, RHW, nals for conductors that are more finely stranded than Class B
RHW-2, THHN, THHW, THW, THW-2, THWN, THWN-2, and Class C stranding as shown in Table E3406.9, shall be
identified for the specific conductor class or classes. (110.14)

TABLE E3406.9 (Chapter 9, Table 10)
CONDUCTOR STRANDING c
NUMBER OF STRANDS
CONDUCTOR SIZE
Copper Aluminum
AWG or kcmil mm 2 Class B Class C Class B
24-30 0.20-0.05 Note a — —
22 0.32 7 — —
20 0.52 10 — —
18 0.82 16 — —
16 1.3 26 — —
14-2 2.1-33.6 7 19 7 b
1-4/0 42.4-107 19 37 19
250-500 127-253 37 61 37
600-1000 304-508 61 91 61
1250-1500 635-759 91 127 91
1750-2000 886-1016 127 271 127
a. Number of strands vary.
2
b. Aluminum 14 AWG (2.1 mm ) is not available.
c. With the permission of Underwriters Laboratories, Inc., this material is reproduced from UL Standard 486A-B, Wire Connectors, which is copyrighted by
Underwriters Laboratories, Inc., Northbrook, Illinois. While use of this material has been authorized, UL shall not be responsible for the manner in which the
information is presented, nor for any interpretations thereof.

692 2018 INTERNATIONAL RESIDENTIAL CODE ®
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