air compressor 220v 15amp in 20amp

[wazzabie]

I'm not wired for 220v. I have a 220v 5hp 30 gallon sears compressor that calls for 15amps. I also have a 4K watt 220v 20 amp generator.

The 220v 15amp plug does not fit with the 220v 20amp socket on the generator. Would it be ok if I created an adapter so I can run the 220v 15amp air compressor on the 20 amp 220v generator?

 

[sam.coll]

I cant see why not but not sure where you are so your wiring rules may differ, making an adapter lead with a 15A plug top 20A socket is generally prohibited/illegal. May be cheaper just to fit a 20A plug top to the compressor lead?

 

[pcmeiners]

Seriously doubt you can run a 15 amp draw compressor on a 20amp generator supply. Compressors have high startup current needs.

 

[kunkernator]

Check out this video...the guy uses a homemade adapter to connect two 110V outlets to run one 220V outlet.

"Experiment convert 110v to 220v from two outlets."

With this adapter you could use one 110V outlet from the garage and one 110V outlet on the generator.

As has been previously stated in other threads on this matter: these are dangerous voltages that can easily kill you or start a fire. So be careful.



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This guy is an idiot. He uses 10 or 12 gauge pigtails off his box, and runs them to 14 or 16 gauge extension cords. Not to mention the outlets they are plugged in to are only rated for 15-20amps, plus the wiring going to the breaker box is likely 14 or 16 gauge, plus the breakers are probably only 15 or 20 amp. And on top of that he is using a 50 amp 220 receptacle.... If those breakers dont trip, this is a disaster waiting to happen. Plus this guy has NO clue on how to actually get 220 out of a panel. The list goes on....

Anyhow, whenever i wire a 220 outlet, i use 8 gauge wire on a 50 amp breaker with a NEMA 6-50 plug (pretty standard for welders/compressors).

I dont know what plug your generator has on it, but there should be no issue with the compressor running on it, assuming you wire a new plug correctly. The only issue is that the startup surge may exceed the 20 amps...

 

[AA/FC]

With this adapter you could use one 110V outlet from the garage and one 110V outlet on the generator.

I doubt it...

In a home garage electrical system, phase A, and phase B are both running at 60 cycles per second. (Hertz) Each phase is running exactly oposite of each other. When one phase is up, the other is down. It's easy to be sure each phase is running oposite of each other becase the source (the power company) makes sure of this. If you use one leg (phase) fromm your garage, and another one from your generator, you have no way of knowing where each phase is within it's cycle.


Yes, you can technically do this using two different outlets in your house or garage but it cant be just ANY two outlets. You need to make sure one outlet is running on a breaker connected to phase A, and the other needs to be on phase B.

 

[md21722]

The motor has a high startup current almost 8X nameplate. Even if you got the plugs to match I wouldn't try it. I would get a 230V circuit run instead.

 

[theoldwizard1]

Seriously doubt you can run a 15 amp draw compressor on a 20amp generator supply. Compressors have high startup current needs.

Done it many, MANY times. I have not actually measured the current, but I made up my own adapter and it works perfect.

Actually, I like using my compressor when "exercising" my generator. That way I know both "halves" of the generators windings are working.

 

[jallyn]

I'm not wired for 220v. I have a 220v 5hp 30 gallon sears compressor that calls for 15amps. I also have a 4K watt 220v 20 amp generator.

The 220v 15amp plug does not fit with the 220v 20amp socket on the generator. Would it be ok if I created an adapter so I can run the 220v 15amp air compressor on the 20 amp 220v generator?

It will probably work. Startup current will be higher than your generator is rated for, but it will probably work. If it trips the generator's breaker then you know it won't work.

If it was my time and money I would install a 220V circuit from your main panel dedicated to your compressor.

 

[QwikKotaTx]

I doubt it...

In a home garage electrical system, phase A, and phase B are both running at 60 cycles per second. (Hertz) Each phase is running exactly oposite of each other. When one phase is up, the other is down. It's easy to be sure each phase is running oposite of each other becase the source (the power company) makes sure of this. If you use one leg (phase) fromm your garage, and another one from your generator, you have no way of knowing where each phase is within it's cycle.


Yes, you can technically do this using two different outlets in your house or garage but it cant be just ANY two outlets. You need to make sure one outlet is running on a breaker connected to phase A, and the other needs to be on phase B.

How is that different than say a 220V breaker that has both legs on the same rail in the box? I was curious about this when wiring up my welder outlet.

 

[md21722]

The breakers typically go A, B, A, B as you go down.

It is NOT like bus bar A on one side and B on the other.

Take a look here:

https://jet.com/product/detail/9ef1...gclid=CKyqw5S8zcwCFQkyaQodc1wN1A&gclsrc=aw.ds

 

[QwikKotaTx]

The breakers typically go A, B, A, B as you go down.

It is NOT like bus bar A on one side and B on the other.

Take a look here:

https://jet.com/product/detail/9ef1...gclid=CKyqw5S8zcwCFQkyaQodc1wN1A&gclsrc=aw.ds

Ok, that's how I'm hoping my panel is configured. I have only added a single pole breaker for outlets thus far. Mine is an Eaton style where the end of the breaker has a hook that goes over the mounting rail.

 

[redmondjp]

I doubt it...

In a home garage electrical system, phase A, and phase B are both running at 60 cycles per second. (Hertz) Each phase is running exactly oposite of each other. When one phase is up, the other is down. It's easy to be sure each phase is running oposite of each other becase the source (the power company) makes sure of this. If you use one leg (phase) fromm your garage, and another one from your generator, you have no way of knowing where each phase is within it's cycle.


Yes, you can technically do this using two different outlets in your house or garage but it cant be just ANY two outlets. You need to make sure one outlet is running on a breaker connected to phase A, and the other needs to be on phase B.

OK, guys, do your homework. It is not two phases! L1 and L2 are the leads of the secondary winding of the step-down transformer, which is center-tapped with this tap bonded to ground and connected to the neutral. The voltage between L1 and neutral: 120VAC. Between L2 and neutral: 120VAC. Between L1 and L2: 240VAC.

L1 and L2 are the same phase.

Now if we are talking about a 120/208V service (3 phase), then any two legs ARE different phases, with 208V between them. But this is not typical of a residential electrical service.

 

[AA/FC]

OK, guys, do your homework. It is not two phases! L1 and L2 are the leads of the secondary winding of the step-down transformer, which is center-tapped with this tap bonded to ground and connected to the neutral. The voltage between L1 and neutral: 120VAC. Between L2 and neutral: 120VAC. Between L1 and L2: 240VAC.

L1 and L2 are the same phase.

Now if we are talking about a 120/208V service (3 phase), then any two legs ARE different phases, with 208V between them. But this is not typical of a residential electrical service.

Lololol. Ok, so replace every "phase" with "leg" in my previous post.

So, are you saying that it IS possible to power a 240 volt compressor using one LEG from your home electrical system, and the other LEG from a generator?

 

[BrokewrenchLS1]

Lololol. Ok, so replace every "phase" with "leg" in my previous post.

So, are you saying that it IS possible to power a 240 volt compressor using one LEG from your home electrical system, and the other LEG from a generator?

I'd be worried about phase imbalance and unequal voltage under load between L1 and L2 there. Electricians and EEs would know more about that, though.

Unless the start-up current surge is too high (possibly solved by a start-up capacitor?), I'm not sure why you wouldn't just run off the 220/230Vac single-phase from the generator, though.

 

[mike93lx]

Anyhow, whenever i wire a 220 outlet, i use 8 gauge wire on a 50 amp breaker with a NEMA 6-50 plug (pretty standard for welders/compressors).

I'm all for overkill but this is a waste of expensive wire and plugs in most situations. Most 240v equipment needs nowhere near 8 awg or a 6-50 plug, like A table saw, jointer, drill press, or compressor. Most will be completely fine on 12 awg and a 6-15 or 6-20 outlet.

 

[kunkernator]

I'm all for overkill but this is a waste of expensive wire and plugs in most situations. Most 240v equipment needs nowhere near 8 awg or a 6-50 plug, like A table saw, jointer, drill press, or compressor. Most will be completely fine on 12 awg and a 6-15 or 6-20 outlet.

According to code, IIRC, all amperage ratings have to match. (I.e, a 6-50 plug must have wire rated for 50 amps (8ga))Anyhow, my welder pulls 40 amps constant on high, and peaks to 46 amps.

But yes, you are correct, generally speaking, 220 equipment doesnt pull that much, my grinder pulls 2.6 amps for instance.

I still dont think that ghetto 220v adaptor is a good idea.

 

[speed bump]

How is that different than say a 220V breaker that has both legs on the same rail in the box? I was curious about this when wiring up my welder outlet.

They don't have both sides on the same leg.

As far as the original question yes a 15a compressor should work fine on a 20a circuit. The circuit breaker has some trip time to deal with the in rush current. If your generator has fuses you want to use a slow blow style.

 

[mike93lx]

According to code, IIRC, all amperage ratings have to match. (I.e, a 6-50 plug must have wire rated for 50 amps (8ga))Anyhow, my welder pulls 40 amps constant on high, and peaks to 46 amps.

But yes, you are correct, generally speaking, 220 equipment doesnt pull that much, my grinder pulls 2.6 amps for instance.

I still dont think that ghetto 220v adaptor is a good idea.

There are exceptions for intermittent use devices (welder). I have a 10 awg wire feeding a 6-50 plug for my welder.
You 8 awg wire is not rated for 50A either, but it's fine for a welder. You'd need to step up to 6awg for a constant 50a load.

 

[Sal Bandini]

You guys ever use extension cords or even make up your own? Or repair one by adding a store-bought connector? Making an adaptor is no different.

Can the male connector handle 15A? Check
Can the wire gauge handle 15A? Check.
Can the female connector handle 15A? Check

Build your adaptor and use it on your compressor/generator combo. It's not a permanent connection anyway.

 

[AA/FC]

I'd be worried about phase imbalance and unequal voltage under load between L1 and L2 there. Electricians and EEs would know more about that, though.......

Exactly. And thats what I was getting at in my original post. Then redmondjp quoted me and said "do your homework". Just because I misused "phase" in place of "leg" doesn't mean the bulk of my post was wrong. Lol.

And just to be clear, I knew the correct term was "leg" not phase..... I just dont deal with this stuff on a daily basis (I'm not an electrician) which is why I never "tell" or "give" electrical advise to other people. In my original post I was basically saying not to do what the other poster suggested.

 

[Sal Bandini]

Since both hots are coming from the same leg the phase angles will always be the same. This is the only way you will get 240V.

You are right if you use one hot from the wall and one from the generator you will not have the phase angles in sync. You will get anything but 240V.

 

[IUEC Medic]

Exactly. And thats what I was getting at in my original post. Then redmondjp quoted me and said "do your homework". Just because I misused "phase" in place of "leg" doesn't mean the bulk of my post was wrong. Lol.

And just to be clear, I knew the correct term was "leg" not phase..... I just dont deal with this stuff on a daily basis (I'm not an electrician) which is why I never "tell" or "give" electrical advise to other people. In my original post I was basically saying not to do what the other poster suggested.

You didn't just use the incorrect term... You (vaguely) did actually describe phasing. He was simply explaining that the two legs brought into an average house are the exact same phase, meaning they both cross 0 at the exact same time.

You incorrectly described that the two legs coming into a house are two separate phases, which are out of phase with one another.

He was saying that, in theory, you could take 110v from two seperate circuits from the same house line voltage, and have 220, but not with the generator. Generator would be out of phase with line voltage.

 

[wazzabie]

So interesting discussion but I got lost.

If I make an adapter for a 220V 15 amp plug on a welder/ air compressor to work with 20amp socket on the 220v generator is this going to work?

 

[redmondjp]

So interesting discussion but I got lost.

If I make an adapter for a 220V 15 amp plug on a welder/ air compressor to work with 20amp socket on the 220v generator is this going to work?

Read post #3 again. I doubt that the generator will be able to start the compressor - maybe if there is zero pressure in the tank. The motor inrush current required to start the motor most likely exceeds what the generator can provide.

Go ahead and try it. The generator will probably sound like you threw a wrench in the flywheel when the compressor motor attempts to start. You'd be much better off with a gas-powered compressor.

 

[IUEC Medic]

Make an adapter and give it a shot. Worst case scenario you trip a breaker or blow a fuse. Best case scenario... It works.

The cord and plug on the load (air compressor) are rated for 220v 15a, and the output on the generator is rated at 220v 20a...

Your load is rated for less than your source is capable of outputting.

 

[Sal Bandini]

So interesting discussion but I got lost.

If I make an adapter for a 220V 15 amp plug on a welder/ air compressor to work with 20amp socket on the 220v generator is this going to work?

Yes. Why would it not? Electrons don't care if it's 20A or 15A connector. All you are doing is extending the wires.

The only issue is whether or not the generator can handle the start up. Only one way to find out.

 

[fatfillup]

I wouldn't run it off the generator. Even if it does work, I am betting the motor will start slow (which isn't good for the motor) and will stress the generator. I am thinking you will shorten the life of both.

While I am not an expert, I have a lot of practical experience with motors and generators, low voltage and high amp damage.

 

[wazzabie]

I tried running it on the gas generator but it was a no go. The engine bogged down and would not give enough power