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Compressor wiring question

Posts

Compressor wiring question

#1

Compressor wiring question

GolfSteve in Calgary

>I bought a compressor with a 240V, 15 amp nameplate motor. It came with a 15 amp plug (two horizontal blades and one ground blade). The motor has its own thermal overload.

I want to wire a new circuit for this compressor. I thought I would use a 20 amp 2-pole breaker, but is it OK to install a 15 amp receptacle on a 20 amp circuit? All wire would be sized for 20 amps.

It just seems strange for me to install a 15 amp breaker for a motor with nameplate 15 amp duty using a 15 amp receptacle. This seems like a recipe for nuisance trips. Any thoughts on this?

Perhaps what I should do is replace the compressor cord with a 20 amp cord, then use a 20 amp breaker and a 20 amp receptacle.

Re: Compressor wiring question

#2

Re: Compressor wiring question

Bob Fawcett

>If the nameplate says 15 amps and it comes with 15 amp plug, that should be fine. Just get a motor rated breaker.

Re: Compressor wiring question

#3

Re: Compressor wiring question

Kent in Emmaus, PA

>Use a 240V, 20A receptacle. It will accept either a 15 or 20A plug.

Re: Compressor wiring question

#4

That's What I Did

Garrett in Victoria BC

>

Re: Compressor wiring question

#5

No

Mark Goodall - ATL - tooljunkie

>"...but is it OK to install a 15 amp receptacle on a 20 amp circuit?"

No. The breaker must be the "weakest link" in order to protect the rest of the circuit. A 15A outlet is technically unsafe over 15A and the breaker would happily allow it up to 20A before it thought it was time to protect it.

But a NEMA 6-15P plug will fit in a 6-20R outlet.

Happy Woodworking!


img

Re: Compressor wiring question

#6

Re: No

GolfSteve in Calgary

>Thanks Mark. My local BORG didn't have any of the 6-20R plugs that would be compatible with the plug supplied by the compressor manufactuer. The BORG only carried the 6-15R plugs, or the 6-20P. Unless I get other advice, or if I find conflicting info in the local codebook when I get back into the office - I'm off to China for 10 days in a few minutes :-( , then I'll put in a 20 amp plug and breaker.

Another data point---the nameplate has 93 L.R. Amps (Locked Rotor?) on it. I was not familiar with that abbreviation, so I googled it and finally got some info that was similar to my situation. The nameplate information in this example is almost identical to the nameplate on my compressor.

However this guy is suggesting that I should use a 40 amp breaker for this compressor (but with a 15 amp plug?)

http://en.allexperts.com/q/Electrical-Wiring-Home-1734/230-Volt-Air-compressor-2.htm

Something doesn't sound right in the above link.

Re: Compressor wiring question

#7

I suspect you made that graphic, Mark…

Rod Peterson -- Ormond Beach

>It's really nice, but “receptacle” is misspelled at all four opportunities.

ESL is tough, isn't it? SWMBO suffers, also. it affects one in places one wouldn't even suspect.

Rod

Re: Compressor wiring question

#8

Dang, you're right :(

Mark Goodall - ATL - tooljunkie

>

👍 This page answered my questions

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