695.4

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hhsting

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Glen bunie, md, us
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I have overcurrent protection for fire pump that satisfies 695.4(B)(2)(a)(2).

If I were looking at TCC curve of breaker then which of the conditions in 695.4(B)(2)(a)(2) would be my breaker pickup setting a, b, c, or d?

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all 4

all 4

You need to satisfy all four conditions. I would set the Instantaneous setting above the locked-rotor-amperage of the fire pump based on the nameplate for the motor. The NEC requirement (a) sets the baseline at 600% for 2 minutes, so I would plot that on a TCC and make sure that it doesn't trip within 2 minutes, and I think the other parameters would be met, but could also be viewed on the TCC.
 
mayanees said:
You need to satisfy all four conditions. I would set the Instantaneous setting above the locked-rotor-amperage of the fire pump based on the nameplate for the motor. The NEC requirement (a) sets the baseline at 600% for 2 minutes, so I would plot that on a TCC and make sure that it doesn't trip within 2 minutes, and I think the other parameters would be met, but could also be viewed on the TCC.
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How would you size EGC then for breaker satiaifies 695.4(B)(2)(a)(2)?

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250.122

250.122

I would size per 250.122, with the max size being that of the phase conductors.
 
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