Help/air compressor tripping 20 amp breaker

I have a 58' run of 12/3 wire running to the shed that operated some
lights and a small 110v sears 30 gallon air compressor nearly new.
The first time or two of turning it on to build air the breaker blows.
After that it seems to be fine the rest of the day, cycling on/off.
Is my wire run to long and making to much of a current drop???
What can I do to stop this. Anyone? Thanks in advance.
Bruce
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Reply to
Bruce
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Are you bleeding the pressure off the tank at the end of each day? If so, don't, leave the tank at full pressure. Do make sure to drain the water out of the tank regularly.
ARM
Reply to
Alan McClure
Not knowing the FLA and LR for the motor try this site for the voltage drop calculations.
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I have a 15 gallon Sears compressor and it says it draws 15 amps.(FLA) According to the site 15 amps and 58 feet results in a 3 volt drop or 2.8% well with in tolerances. Max is 5%. The extra for the lights might be the problem Have you tried another breaker? Residential breakers do get tired and trip early after a long time. My home is 30 years old with SQ NQO breakers, I have replaced the exterior breakers and the pool circuit they just trip to much
Reply to
SQLit
15Amp FL this might also be a breaker rating issue is it a type C breaker for motors? Darren Fletcher
Reply to
Darren Fletcher
Well, on a small label near the load screw it has QD SWD. Would a 110v motor have a cap that could release some of its reservduring a period on non use?
Reply to
Bruce
The breaker has on it QD SWD. Does this small motor have a start cap that can lose stored energy over a short period of time? I just switched with another breaker and will see. Still looking for a fix in case the lights dim way down. Thanks again, Bruce
Reply to
Bruce
What good would draining the tank do, unless you empty it before every compressor start??? A "decent" compressor should have an unloader valve between the compressor and tank so it starts without having a load on it. The OP should check to make sure his unloader is working, if so equipped.
I never empty my compressor tank, but do drain the condensate out regularly and change the oil every so often. It's about 30 years old and working fine.
Reply to
BG
Start caps are AC devices so they don't store energy between starts.
The problem is quite common starting a small compressor. The inrush current for an electric motor is about six times the FLA, or 90 odd amps for a fraction of a second. An ordinary domestic breaker will not handle this with a cold motor where the duration of the inrush is longer than when it is warm. You are right on the edge. Consider getting a breaker rated for a motor start. Fit it in a separate breaker box if necessary, alongside the main panel.
Reply to
Rusty
Read what I said again, the comma after the don't has meaning in this instance. To rephrase, don't bleed the pressure off the tank at any time. Always try to leave the tank at full pressure and water drained out.
Thanx for the reminder on the unloader valve. I had forgotten about it.
Note: the unit the OP described is the same as mine and it is oil-less and noisey.
I had this problem when I first got my compressor and I just remembered that if I turned it off before it got to full pressure and tripped the unloader and shut down the motor it would trip the breaker when I tried to restart it. Note to OP: let the compressor come up to full pressure and stop by itself before turning it off.
ARM
Reply to
Alan McClure
"240.83(D) Circiuit breakers used as switches in 120-volt and 277-volt fluorescent lighting circuits shall be listed and shall be marked SWD or HID. [marked HID for high-intensity discharge lighting]
Use another breaker. It's doubtful that a company would build a home and leave enough amperage left over on a lighting circuit to run your compresser.
Keep your compresser separate from the lighting circuit. Otherwise no matter what you do you'll probably have the same problem. That might mean running a new circuit for it. It should be on its own circuit anyway.
Reply to
Zzzap
"I see," said the blind man. Sorry about misreading your post.
Reply to
BG
No worries, mon. ARM
Reply to
Alan McClure

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