Notice: NEC is a registered trademark of the National Fire Protection Association, Inc.  All NEC references by Electrical Helper are interpretations of the NEC by the Electrical Helper staff and are not NEC statements. The official position of the NEC requires that the NEC be referred to in its entirety.
	The rules and requirements set forth in the NEC are for protecting you and your property.
	We must take the work environment into consideration when sizing our conductors. Just as the National Electrical Code states in Table 310.10 below and is the reason we have included the different wire temperature ratings for your use.
	310.10 Temperature Limitation of Conductors. No conductor shall be used in such a manner that its operating temperature exceeds that designated for the type of insulated conductor involved. In no case shall conductors be associated together in such a way, with respect to type of circuit, the wiring method employed, or the number of conductors, that the limiting temperature of any conductor is exceeded.
	FPN: The temperature rating of a conductor [see Table 310.13(A) and Table 310.13(C)] is the maximum temperature, at any location along its length, that the conductor can withstand over a prolonged time period without serious degradation. The allowable ampacity tables, the ampacity tables of Article 310 and the ampacity tables of Annex B, the correction factors at the bottom of these tables, and the notes to the tables provide guidance for coordinating conductor sizes, types, allowable ampacities, ampacities, ambient temperatures, and number of associated conductors. The principal determinants of operating temperature are as follows: (1) Ambient temperature — ambient temperature may vary along the conductor length as well as from time to time. (2) Heat generated internally in the conductor as the result of load current flow, including fundamental and harmonic currents. (3) The rate at which generated heat dissipates into the ambient medium. Thermal insulation that covers or surrounds conductors affects the rate of heat dissipation. (4) Adjacent load-carrying conductors — adjacent conductors have the dual effect of raising the ambient temperature and impeding heat dissipation.