Do I need a 50 amp breaker

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Old 05-28-11, 07:56 AM
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Do I need a 50 amp breaker

I bought a really good sub pump for my basement. Its 115 VAC. At start up, it draws 47 amps, than, runs on 11 amps. I'm just curious if I need a 50 amp breaker. Thanks. John.
 
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Old 05-28-11, 08:00 AM
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It should say what the circuit fuse or breaker rating should be. Motors have different rules compared to stoves or water heaters. Just guessing, but I would imagine 20A would be correct....possibly even 15A...but then those rules come into play again...lol.
 
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Old 05-28-11, 08:04 AM
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No. A regular breaker can take a sudden over current for a few seconds before it trips. The pump would probably run ok on a dedicated 15a breaker with #14. However I'd suggest a dedicated #12/20a circuit.

If by sub pump you mean sump pump it will require GFCI protection. Either a GFCI breaker or a GFCI receptacle are ok.
 
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Old 05-28-11, 08:09 AM
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Originally Posted by ray2047 View Post
No. A regular breaker can take a sudden over current for a few seconds before it trips. The pump would probably run ok on a dedicated 15a breaker with #14. However I'd suggest a dedicated #12/20a circuit.

If by sub pump you mean sump pump it will require GFCI protection. Either a GFCI breaker or a GFCI receptacle are ok.
Yes, I meant sump pump I'm sorry. Thanks guys for your answers.
 
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Old 05-28-11, 10:42 AM
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Very general rule for motors is to size the circuit breaker at 175% of the full-load amperage of the motor. Some circumstances may allow up to 250% but smaller is better as long as the motor starts okay.

Unless the pump has a high lift (distance from the bottom of the sump to the top of the discharge pipe) AND/OR a minimally sized discharge pipe diameter the pump will most likely be fine on a 15 ampere branch circuit. Wiring with number 12 conductors all the way back to the circuit breaker would allow using a 20 ampere circuit breaker if it became necessary although in some specific installations number 14 conductors could be used even with a 20 ampere circuit breaker.
 
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