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Connecting Compressor - plug/outlet mismatch

SprintCC

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Jun 20, 2005
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37
Location
Raleigh, NC
Self admitted electrical noob, it scares the crud out of me. About the only thing I know for sure is it can ruin my day.

It's my understanding that you can connect a tool that uses less amps to an outlet that provides more amps, it will only use what it needs. Connecting the other way around (pulling more amps than the outlets meant for) is asking for trouble. If so I should be able to use my 220v 15 amp compressor on a 220v 30 amp circuit. Am I understanding this right?

Starting to get my garage together after my move. The previous owner had put a 220 outlet in the garage - I've ID'd it as a NEMA 10-30 old style (3 prong) drier plug. I've verified at the box that it's hooked up to a 30 amp double breaker, & via my digital multimeter it's running 220 (actually about 250).

I have a Craftsman compressor, 220v, 15amp. It didn't come with a plug so the guy who did the electrical in my garage 2 houses ago (last time it was running) put on a NEMA L6-20 plug.

Obviously these 2 do not connect. Am I better off to:
1) attempt to find an adapter to mate the 2
2) change the plug on the compressor chord
3) change the wall outlet (I'm not even sure this is a viable/safe option).
4) give it up, get another line run.

Recommendations?

Thanks!
Chris
 
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Vahispd

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Nov 21, 2012
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141
Location
SE VA
It's my understanding that you can connect a tool that uses less amps to an outlet that provides more amps, it will only use what it needs. Connecting the other way around (pulling more amps than the outlets meant for) is asking for trouble. If so I should be able to use my 220v 15 amp compressor on a 220v 30 amp circuit. Am I understanding this right?
Yes, your understanding is correct.

Starting to get my garage together after my move. The previous owner had put a 220 outlet in the garage - I've ID'd it as a NEMA 10-30 old style (3 prong) drier plug. I've verified at the box that it's hooked up to a 30 amp double breaker, & via my digital multimeter it's running 220 (actually about 250).

I have a Craftsman compressor, 220v, 15amp. It didn't come with a plug so the guy who did the electrical in my garage 2 houses ago (last time it was running) put on a NEMA L6-20 plug.

Obviously these 2 do not connect. Am I better off to:
1) attempt to find an adapter to mate the 2
2) change the plug on the compressor chord
3) change the wall outlet (I'm not even sure this is a viable/safe option).
4) give it up, get another line run.

Recommendations?

Thanks!
Chris

What do you plan to do in the garage, and/or with the 220v outlet? Answering that question will help determine which option is the best for you.
 

sberry

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Depends on if it came with a factory cord or not, it could need a specific current limited circuit. I don't recall if those little Sears units came cord and plug,,,, is this an upright stationary unit? As a guess it probably is, it might be fine on a 30.
 
Last edited:

joe_padavano

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Feb 26, 2011
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Northern VA
In the time it took to discuss this, you could have fabricated a short jumper with the 30A plug on one end and the 15A socket on the other.
 

EOC_Jason

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Bentonville, AR
If you aren't going to be using the compressor in other locations then replace the plug on the end of the compressor to match the receptacle and you should be good to go.
 
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Phantomd

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Aug 26, 2015
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183
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Near Boulder CO
This is a basic problem with an easy solution. Replace the plug on the house with an L6-20R (to match the plug on the compressor) and move on with life. (or change the plug on the compressor)


It's common to wire in a 50a (Nema 6-50) socket with only a 30a circuit breaker. Most home mig welders only draw 25a or so. The safety concern here is to make sure the wires in the wall match the breaker in the panel. if you oversize the breaker to the undersized wires then you have a fire hazard. The wire size is dependent mostly on the breaker size and also the length of run.
 

wyliesdiesels

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Modesto, CA
Need to back up.

Whats the HP rating on the motor?

If more than 3HP, then it must be hardwired.

Having said that, the cord and plug need to be rated for the HP rating of the motor so the L6-20p might not be rated cprrectly. Also, a 240v motor does not need a neutral so the 10-30 should definitely be changed if you do go the cord and plug route.
 

alfredeneuman

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Fullerton, CA
The way to turn a white wire to a ground is simple. Just strip the insulation off any place it is exposed.
That way you could use the existing wire and change the receptacle and breaker to the proper configuration.
 

sberry

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Brethren, Michigan
How I would do it might depend on if I had free **** or not and if it came from service main or was fed from a 4 wire panel. If I was goin to have to buy parts would likely get 6-50 and put there, be all set for a modern compact welder. If this is a stationary unit ,,, like it has a 60 gallon tank and all it will run from a 30 breaker. 15Ais 3 hp, who knows what sticker they put on then, but never burn the place down with a 10 cable and a 30 breaker.
Some of those little Sears portables might have come 20A end, just cant remember.
 
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wyliesdiesels

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Modesto, CA
The way to turn a white wire to a ground is simple. Just strip the insulation off any place it is exposed.
That way you could use the existing wire and change the receptacle and breaker to the proper configuration.

As long as its connected to a main service panel.

If subpanel, then need to move that wire over to ground bar.
 
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