HELP w/Plug in compressors

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sunelectricbx

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Boca Raton, Florida
I just installed 2 20A single dedicated circuits for 2 plug in compressors with a FLA of 13.8 (just like the ones the carpenters use for there nail guns) They are being used for Mystic spray tan booths. Every week or so one trips, we metered them at a range of 12-15A. So we changed the breakers. 2 weeks later they tripped again. We repaced the wiring and receptacles and it happened again. Can someone help??? Can i put 30A breakers on compressors so small (plug-in)??? Is it the starting current?
 
Just curious how long the branch circuit run is? I'm betting it's pretty short?

I'd say it's probably the starting current. I'm not very familiar with these compressors, but I'm guessing that they don't have an unloader to eliminate starting under pressure?

It's probably tripping due to starting against the pressure in the tank rather than an empty tank. If the spray system can handle it, you may try to reduce the pressure regulator so that the system pressure is lower when the compressor cuts in. Again, it depends on the controls of the compressor.


John
 
I've had a similar problem with a compressor in my garage. The thing has a 15 amp attachment plug and is on an individual 20 amp CB about 20' from the panel. 1 out of every 4 times it will trip on start up. So I changed the CB to a new 20 amp. Still trips. When I presented this problem on this forum a year or so ago the consensus was that the compressor was defective. Since it was out of warrantee I was stuck with resetting the CB when it tripped. When I suggested putting it on a 30 amp CB, (it's in my own garage after all) the word "hack" quickly came out. :)
 
Just a different train of thought.

Are the compressor unloaders working correctly.

Unloaders are usually contained in the pressure switch.

The unloader releases the pressure that is in the pump cylinder, if the pressure is not released the motor can not start the pump.
 
The strange thing is that it only happens every 2 weeks. The spray booth company came and changed out the compressors after I told them it was nothing electrical.
Can you upsize the breaker 250% (430.52) on a plug in motor? That would allow a 30A breaker. :?:
 
I would try installing "High Magnetic" breakers on these two units. They have a higher instant trip setting than normal breakers. I've solved a few random, nuisance trip problems with HM breakers.

If you can't find those, the "HID" version breakers have the same trip curves, so they will do the job as well.

mike
 
If you change the breakers to 30 amp you will most likely fry the compressor motors. The 20's are to only thing saving them. It is definitly the unloaders causing the problem. Most of the unloaders are adjustable to ensure a positive trip. You might want to try that.
 
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