Question about voltage drop on a 200 foot run

I got called to a warehouse in Medford last Thursday where a new compressor kept tripping the breaker on startup. The run from the panel was about 200 feet through conduit and the voltage at the disconnect read 198 volts under load. Anyone else see big voltage drops on long runs like that causing nuisance trips?

3 comments

3 Comments

robin89616d ago

Meh, voltage drop's overblown half the time.

tessalane17d ago

I’ve dealt with a 200 foot run like this before on a similar compressor setup. The voltage drop is likely too high for the motor’s starting current, so you need to bump up to #4 copper or even #2 if the load is heavy. A buck boost transformer at the disconnect can help too, but bigger wire is usually the cleaner fix.

dylanrodriguez17d ago

Wait, 200 feet for a compressor and you're suggesting buck boost transformers? Might as well just run an extension cord from the neighbor's house and call it a day. I mean, at that point you're basically building a mini substation in your garage.