![]() ![]() Tl dr Conductors and all terminals rated at or above 75☌. The underground conductors between the utility distribution system and the service point. The service conductors between the terminals of the service equipment and the point of connection to the service lateral or underground service conductors. Service-Entrance Conductors, Underground System. ![]() The service conductors between the terminals of the service equipment and a point usually outside the building, clear of building walls, where joined by tap or splice to the service drop or overhead service conductors. Service-Entrance Conductors, Overhead System. " shall be permitted as 120/240-volt, single-phase service-entrance conductors and service lateral conductors".Īfter reading the definition of these terms, it's clear that this does not apply to the wire between the main panel and a subpanel. (a) For individual dwelling units of one-family, two-family, and multifamily dwellings, conductors, as listed in Table 310.15(B)(7), shall be permitted as 120/240-volt, single-phase service-entrance conductors and service lateral conductors. (7) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services and Feeders. The temperature correction and adjustment factors shall be permitted to be applied to the ampacity for the temperature rating of the conductor, provided the corrected and adjusted ampacity does not exceed the ampacity for the temperature rating of the termination in accordance with the provisions of 110.14(C). Ampacities for conductors rated 0 to 2000 volts shall be as specified in the Allowable Ampacity Table 310.15(B)(16) through 310.15(B)(19), and Ampacity Table 310.15(B)(20) and Table 310.15(B)(21) as modified by (B)(1) through (B)(7). If you're working in a one-, two-, or multi-family dwelling unit, is Article 310.15(B)(7) applicable? National Electrical Code 2014 ARTICLE 310 Conductors for General Wiringģ10.15 Ampacities for Conductors Rated 0–2000 Volts. This will give us the current carrying conductor size required for our feeder. Once we know the size of the overcurrent devices, and the lowest temperature rating, we can use Table 310.15(B)(16) to determine the conductor size and material we'll need. We'll then use the lowest value, or 60☌ if any of the above are not labeled. The terminals in the sub panel where the conductors will connect.The terminals in the main panel where the conductors will connect.We have to consider the temperature rating of. Since the cable will run from a breaker in the main service panel, to either a breaker or lugs in a subpanel. (4) For motors marked with design letters B, C, or D, conductors having an insulation rating of 75☌ (167☏) or higher shall be permitted to be used, provided the ampacity of such conductors does not exceed the 75☌ (167☏) ampacity. ![]() (3) Conductors with higher temperature ratings if the equipment is listed and identified for use with such conductors. (2) Conductors with higher temperature ratings, provided the ampacity of such conductors is determined based on the 60☌ (140☏) ampacity of the conductor size used. (a) Termination provisions of equipment for circuits rated 100 amperes or less, or marked for 14 AWG through 1 AWG conductors, shall be used only for one of the following: Unless the equipment is listed and marked otherwise, conductor ampacities used in determining equipment termination provisions shall be based on Table 310.15(B)(16) (formerly 310.16) as appropriately modified by 310.15(B)(6). ![]() The determination of termination provisions of equipment shall be based on 110.14(C)(1)(a) or (C)(1)(b). National Electrical Code 2014 ARTICLE 110 Requirements for Electrical Installationsġ10.14(C)(1) Equipment Provisions. We should use the 60☌ column of Table 310.15(B)(16) to determine the conductor size, unless the equipment is listed and labeled for a higher temperature. 110.14(C)(1)(a) tells us, that since we're working with 100 amperes or less. While the cable/wire may be rated at 90☌, you'll likely find that the terminals are rated at 75☌, or not labeled at all. When determining feeder conductor size, you'll want to consider the " lowest temperature rating of any connected termination, conductor, or device" as per National Electrical Code (NEC) Article 110.14(C). ![]()
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