![]() This article explains how to estimate the electrical service size, (or "electrical power" or "service amps") at a building by visual examination of theīuried service entry cables and other details that are available by simple visual inspection. We also discuss, for building inspectors or owners, how to determine the size, capacity, or ampacity of electrical service at a building. We have no relationship with advertisers, products, or services discussed at this website.īuried or underground electrical service entry cable ampacity & underground electrical service ampacity ratings: what are the required electrical cable sizes & types, conduit sizes, and burial depths for underground electrical service entry wiring? This guarantees the safe use of aluminum wires for electrical purposes.InspectAPedia tolerates no conflicts of interest. ConclusionĪn aluminum wire ampacity chart can help you decide which wire you can use based on temperature.Īs long as you know the ambient temperature and the number of wires you will use in a cable or raceway, you can directly use the table values to buy your tools as needed. Thus, the maximum current should be 28.7 amps (35 amps times 0.82). Table values based on ambient temperature of 40⁰Cįor example, if we use 10-gauge aluminum THHN wires at an ambient temperature of 50⁰C, then their maximum current should be corrected by 0.82. Table values based on ambient temperature of 30⁰C If you will use more than three current-carrying conductors in a cable or raceway, then the values in the table should be reduced to the following percentages based on the number of wires: More Than Three Current-carrying Wires in a Cable or Raceway The ratings must be adjusted to prevent the wires from accumulating too much heat that can damage the insulation. If the conditions for using the table are not met, then correction or “derating” should be done to safely use an aluminum wire. A 10-gauge aluminum THHN wire at 90⁰C can handle up to 35 amps.Ĭorrection or Derating Aluminum Wire Ampacities Then check the wire gauge and look at the amp rating of wire at its maximum temperature.Check the maximum temperature the insulation can handle.If the previous conditions are met, then you can check the table for a quick answer: Let’s say you want to know how much current a 10-gauge aluminum THHN wire can carry. Most common applications, though, are rated at 90⁰C. The values in the table should be corrected or derated for the number of wires and ambient temperature. If the conditions are not met, then this wire size chart cannot be directly used. The values for 60⁰C, 75⁰ and 90⁰C are true at an ambient temperature of 30⁰C, while the values at 150⁰C are true at an ambient temperature of 40⁰C. The values for 60⁰C, 75⁰ and 90⁰C are also true for direct-burial cables with up to three single conductors. The wires are in a cable or raceway with up to three single conductors. ![]() We can directly use the table values if we meet the following criteria: The rated ampacities in the table are the maximum current the aluminum wire can safely carry without damaging its insulation. ![]() Generally, the ampacity is limited by the wire’s insulation. ![]() ![]() The table lists the ampacity of wire based on the wire size and temperature. Includes SA, THHN, THHW, XHH, XHHN, XHHW, XHWN and USE-2, among others THW, THWN, USE and ZW wires, among others Ampacity table for insulated aluminum or copper-clad aluminum conductors ![]()
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