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Help w/ electricity

1098 Views 10 Replies 9 Participants Last post by  Wes V
I just got an air compressor that runs on 220. Unfortunately I don't have a 220 outlet in the workshop other than the one for the house water heater. The plugs are different...but is the electricity the same? Can I just put the correct outlet in that box? Any other considerations? Can a 110 outlet be converted to 220? How?

Thanks!

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Rick Sutter
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'67 SS 396
San Antonio, TX
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Rick

The best option you have is to get a qualified electrician to install a dedicated 220 circuit for your workshop. Do it right! Every year hundreds of homes go up in smoke caused by faulty electrical wiring. This is not to say you are not able to do it yourself. Depending on the location of your breaker panel and of there is room for an additional 220 breaker. It may turn out to be an easy job. Ask around you may be able to get qualified help for little or no money, if that is a concern.
some air compressors can run on eother 220 or 110....fact is that if you have that option, it is safer to run it on 220 because the amperage it draws will be 1/2 that it will draw at 110...significance of this is that the wires supplying the compressor will stay cooler because the heat buildup
(= amperages quared X resistance of circuit)
is proportional to the square of the amperage...ie 4X as much heat at 110 (double the amperage squared = 4X) than at 220....
i am running my 2 hp compressor at 110 and almost melted the outlet and plug one day becasue i was using it for a long procedure....good way to start a house fire..

correct way to convert to 220 is to run a 10 guage 4 conductor wire from you distribution box to the outlet (or to a new outlet)
2 leads are o hot opoosite sides of the box and 3rd is current carrying ground...4th is another ground...easy if you know how but dangerous to do if you dont know what you are doing so i wouldnt advise you to do it from insrtuctions i could give in this forum...running the wire is the toughest part..once run hookup is a matter of minutes so maybe an electrician wouldnt be much more than a service call if you run the wire and mount the box in advance....be safe!!

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Rich
Cocoa Beach, Fla
Team Chevelle #380
[email protected]
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do it right, install a 220 line in your garage or workshop, but if you must is there a clothes dryer close?, you might have to change the plug or use an adapter.

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Been there done that!! You need a blank space in your elec. box. Then run a wire ( for 220) from your house box to another box with a on and off switch. Then go from there to your compressor and then you can eliminat the plug if you like. Probably better to hire some one. Steve
I know the "right" way to do it is to call an electrician and I'm planning to call and check on it. I'm scared of what the bill is going to be though. The box is about 15 feet from where I want the outlet so it wouldn't be hard to run the wires. I've done some 110 wiring and stuff but since I've never done anything with 220, I thought maybe I could get away with just changing the outlet or using an adapter at the water heater plug.

I think you're right Rich, I'll just run some wire to a box and have the rest done...just a drop in the bucket compared to what the rest of this car is going to cost


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Rick Sutter
Member #383
'67 SS 396
San Antonio, TX
www.sutternet.com/chevelle.asp
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Rick:

The reason the plugs are different is because the amperage is different. Each voltage and amperage has a different shaped plug. You need to use a different breaker for your compressor than for your dryer. I am guessing that the dryer draws more current than the compressor so you MIGHT be able to get away with connecting a second breaker to the dryer and connecting your compressor to that. DO NOT just connect the compressor to the dryer connection since you will likely be over - fused - thus have NO protection against shorts. My advice is to consult an electrician - the amount of damage that can be done by 30 Amps at 220 V is enormous - and your insurance will be invalidated if they find out after a fire. Sorry - but I'd rather be safe.

Steve

OOPs - sorry - read water heater for dryer. This goes double - usually the water heater is a VERY heavy load

[This message has been edited by swild (edited 10-15-99).]
Well obviously, you guys have got him scared by now, so I won't say a thing, but you're right.

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Tom Parsons
There is little difference between wiring for 220 compared to 110 but caution is the operative word here.

There are several things that you should NOT do:

Don't even think about running a 220 appliance on 110. Do not re-wire a 220 appliance with a different connector to use on a 220 circuit. The connectors are different on purpose. Each is rated differently.

If your compressor has the same connector as your heater or dryer, then you are fine. If not:

Find the current rating of your compressor. Take a trip to your local home center and get a 220 breaker that will fit your breaker box. Get enough 10ga or 12ga four conductor wire (3 plus a ground). The guage will depend on the current of your compressor. The box or the floor guy will tell you which is OK.

If your garage/shop has open studs, then the wire can be romex (standard wire) and it can be run through drilled holes in the studs.

If your garage/shop is drywalled, you can't use romex. You have to buy conduit. There are three types:

PVC-Make sure it is schedule 40 (rated for electrical). You will need several fittings, glue, elbows, etc.
METAL-not flexible. You will also need fittings, etc., and a bender.
BX-This is flexible metal conduit. Fewer do-dads are required and no bending.

In any case, your local code may require a separate switch close to the outlet. Ask the guy at the home center.

I would recommend getting all that you need, run all the wire and conduit around your shop, wire the switch (if needed) and the outlet. Do everything but the actual connection to the breaker box. If you are uncomfortable, have the electrician install the breaker and connect it up.

In any case, whether you do it all yourself or have the electrician to it all, it shouldn't cost too much.

Hope that helps.

Bob
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Ok guys I have 25 years in the electric power generation and distribution industry. We, SRP currently have some 700.000 customers. I have seen way to many do-it yourself installations that were down right dangerous. This is why I recommend getting professional help. Someone that will come to the sight to determine wire size, breaker size and type of connection needed. Some 220 circuits need 3 conductor with ground i.e. electric ranges, electric clothes dryers, which use both 220 and 110 so a neutral is needed. Other 220 circuits only need 2 conductor with ground i.e. air conditioning units, water heaters, typical small air compressors, which don't use 110 so a neutral is not needed. It won't hurt to have an extra conductor but it can be confusing when it comes time to wire the correct outlet for the application.

Judging by the questions you asked, Rick you don't have a good enough understanding of electricity to attempt an installation without qualified assistance. You can't count on the home center employee being qualified. I don't mean to "scare" anyone. However it scares me when I get shocked opening the door of a travel trailer, hot and neutral crossed in the outlet. This is just one of hundreds of scary do-it-yourself wiring jobs.
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RickS;

I think the least costly way to do it would be to find an electrician that is willing to work with you.

You could run the metal conduit (flex or rigit) and then pull the wires (gauge and insulation type per his recommendations). Then have him come out and review your work and hook up everything. Make it clear that he has the ability to not pass your work!

Be VERY careful at the fuse block. The ONLY way you can make it not HOT is by pulling off the meter!!!! There is normally a metal band with lead seal that the power company puts on it. If this is removed, the power company WILL question why! (and justifably so)

If you question your abilities, DON'T DO IT!

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Wes. Vann
Technical Reference & Wagons sections
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