Hey all, new here. I have been reading about wiring the pressure switch and this is what i found. I have an old 30gal Quincy air compressor. Started blowing the high pressure relief valve. After some reading here i find it's the pressure switch. Mine looks original. The mother is a craftsman i can't see any details on the plaque but can see it's a craftsman. The plug end has 3 prongs. But inside the switch, there are only 2 wires. And what i see is someone took the power cable from the motor and opened the covering. They cut the black wire and connected 1 side to M1 on the switch and the other side of the black wire to theL1 terminal. No green ground. And the white wire was left alone. I am pretty sure this is not wired right. I plan on replacing the power cord with a proper 3 prong. Now would i ground the green because the motor side is a 2 wire plug. any help would be appreciated.
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air compressor wiring question
- Thread starter krallstar
- Start date
is it a 120 or 240 volt motor?
and, yes, it needs to be grounded
and, yes, it needs to be grounded
120 volt. Can't tell what size motor is. Plate can't be read The tank says built 1961. It runs, got it free. the main feed in from the pump head has a fitting for the newer pressure bleed from head to switch. Switch has no fitting. Looks like they leave it slightly loose for pump bleed down. I posted a pic in Lighting and electrical of the switch. i plan on replacing the power cord with a 3 prong plug, then wire properly. The motor wires only have 2 wires. Not sure what to do about that.
Wrench97
Well-known member
The ground should not switched simply hooked to a metal part of the compressor.
For 120v only the back wire needs to be hooked to the switch terminals.
For 120v only the back wire needs to be hooked to the switch terminals.
It's not necessary to switch the neutral wire(white) but it sure doesn't hurt.
I saw your pic & that sure looks like an old switch. be careful with that tank too, I'd be a bit leery of it
add a ground to the body of the motor
I saw your pic & that sure looks like an old switch. be careful with that tank too, I'd be a bit leery of it
add a ground to the body of the motor