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What is the maximum current allowed on a #10 THW when in a conduit with 5 other current-carrying #10 THW's and two bare #10 grounding conductors?

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Final answer:

The maximum current for a #10 THW wire in a conduit with 5 other current-carrying #10 THW wires, after applying an 80% adjustment factor for more than three current-carrying conductors, is 24 amps. The two bare grounding conductors do not affect the ampacity calculation.

Step-by-step explanation:

The maximum current allowed for a #10 THW wire in conduit with other current-carrying conductors is determined by the National Electrical Code (NEC) ampacity tables and must also consider the adjustment factors for conduit fill and ambient temperature.

According to the NEC, #10 THW copper wire typically has an ampacity of 30 amps under normal conditions. However, when more than three current-carrying conductors are in a conduit, an adjustment factor must be applied. In this case, with six current-carrying #10 THW wires, the adjustment factor is typically 80%. Therefore, the adjusted ampacity would be 30 amps times 80%, which equals 24 amps. Note that this is a simplified analysis and actual conditions such as ambient temperature and conductor insulation may further affect the allowable ampacity.

The two bare #10 grounding conductors do not count as current-carrying conductors for the purpose of applying adjustment factors, as grounding conductors only carry current in fault conditions and do not contribute to the conduit's thermal load under normal operations.

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