National Electrical Installation Standards

Standards as High as Your Own

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Friday, December 21, 2018

Question:

I have a 240 volt 2 # 6thhn + # 10 gr (3 wire) no neutral hot tub. The hot tub is fed from a spa gfci 60 amp disconnect. The spa 60amp disconnect is fed from the main pnl with 2 # 6 thhn + a 10 gr can I use a # 10 neutral since it is only used on the spa neutral bar so the neutral off the gfci breaker can tie into the main pnl neutral and the gfci breaker will function correctly

Don Sieber

A

Answer:

Hey Don thanks for your question. Yes. The minimum feeder neutral conductor size is determined using 220.61 based on the neutral load which in your case is the internal GFCI electronic components. The feeder grounded conductor (also the neutral in your example) must be not smaller than given in 250.122 as stated in 215.2(A)(2). Based on the 60 ampere overcurrent protective device a 10 AWG copper grounded (neutral) conductor in addition to the 10 AWG equipment grounding conductor is acceptable.

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