Blowing fuses on startup

Mar 21, 2011
14
Grosse Tete LA
I saw someone post almost the exact problem earlier today, but didn't want to hijack his thread. My Goldline SWG system has a Pentair challenger pump 1 1/2 plumbing with a booster pump running off a 220 circuit with a disconnect then a Intermatic 220 timer box right by the pump. It's a fused disconnect, with a blade disconnect. The sub panel is run off my main panel off a 50A dual breaker. During the winter at some point both fuses popped when the pump turned on for it's daily cycle. I haven't had time to fix this, but the pool has turned into a hot mess so my attention is now on getting this back up and running.

Last year the bearings where whining on the main pump but made it though the summer. Since I'm assuming the 10 year old motor is causing the fuses to pop, I'll order another and a new seal. Questions are is this common for old motors to blow fuses? And secondly, I live out in the country so running to get fuses is impractical. Is there a valid reason to have fuses in the disconnect, or can I rely on the main panel breaker?
 
Short answer, yes you need the fuses to protect the wiring to the pump.

What amps are the fuses? Probably not 50A? What size is the wiring to the pump? Probably not sized to carry 50 amps. So you can’t rely on a 50A CB to protect the pump wiring.

The hassle of getting fuses is why CBs were invented.
 
You should have a 20 amp fuse in there if wire is 12 gauge. For 30 amps you need 10 gauge.

If a pump blew a 30 amp fuse it definitely has a problem. Pump should pull less than 16 amps.
 
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