are so listed shall be permitted to be designated as weather and water resistant with the suffix "W" after the code type designation. Cords with the "W" suffix are suitable for use in wet locations.
400.5 Ampacities for Flexible Cords and Cables.
(A) Ampacity Tables. Table 400.5(A) provides the allow- able ampacities, and Table 400.5(B) provides the ampacities for flexible cords and cables with not more than three current-carrying conductors. These tables shall be used in conjunction with applicable end-use product standards to ensure selection of the proper size and type. Where cords are used in ambient temperatures exceeding 30°C (86°F), the temperature correction factors from Table 310.16 that correspond to the temperature rating of the cord shall be applied to the ampacity from Table 400.5(B). Where the number of current-carrying conductors exceeds three, the allowable ampacity or the ampacity of each conductor shall be reduced from the 3-conductor rating as shown in Table 400.5.
Table 400.5 Adjustment Factors for More Than Three
Current-Carrying Conductors in a Flexible Cord or Cable
Number Percent of Value in Tables of Conductors 400.5(A) and 400.5(B)
4-6 80
7-9 70
10 - 20 50
21-30 45
31-40 40
41 and above 35
(B) Ultimate Insulation Temperature. In no case shall conductors be associated together in such a way with respect to the kind of circuit, the wiring method used, or the number of conductors such that the limiting temperature of the conductors is exceeded.
A neutral conductor that carries only the unbalanced current from other conductors of the same circuit shall not be required to meet the requirements of a current-carrying conductor.
In a 3-wire circuit consisting of two phase conductors and the neutral conductor of a 4-wire, 3-
phase, wye-connected system, a common conductor carries approximately the same current as the line-to- neutral currents of the other conductors and shall be considered to be a current-carrying conductor.
On a 4-wire, 3-phase, wye circuit where more than
50 percent of the load consists of nonlinear loads, there
are harmonic currents present in the neutral conductor
and the neutral conductor shall be considered to be a
current-carrying conductor.
An equipment grounding conductor shall not be considered a current-carrying conductor.
Where a single conductor is used for both equipment grounding and to carry unbalanced current from other conductors, as provided for in 250.140 for electric ranges and electric clothes dryers, it shall not be considered as a current-carrying conductor.
Exception: For other loading conditions, adjustment fac- tors shall be permitted to be calculated under
310.15(C).
FPN: See Annex B, Table B.310.11, for adjustment factors for more than three current-carrying conductors in a raceway or cable with load diversity.
400.6 Markings.
(A) Standard Markings. Flexible cords and cables shall be marked by means of a printed tag attached to the coil reel or carton. The tag shall contain the information required in 310.11(A). Types S, SC, SCE, SCT, SE, SEO, SEOO, SJ, SJE, SJEO, SJEOO, SJO, SJT, SJTO, SJTOO, SO, SOO, ST, STO, STOO, SEW, SEOW, SEOOW, SJEW, SJEOW, SJEOOW, SJOW, SJTW, SJTOW, SJTOOW, SOW, SOOW, STW, STOW, and