If the auto motor on and air compressor switch has 2 wires black and white and 1 ground wire going to plug The plug is for a dryer with 4 wires Which wires connect together?

Answer for USA, Canada and countries running a 60 Hz supply service.A dryer outlet is only safe to use for one purpose: to power a dryer.

Obviously you can attempt to use it for something else, such as an air compressor, but it is NOT SAFE to do it!

You could drive around on the wrong side of the road but it is NOT SAFE to do it!

You could put your hand into a fire and hold it there but it is NOT SAFE to do it!

In general the reasons for saying it is not safe to use something other than a dryer on a dryer outlet are all about being sure that the circuit you will use for the air compressor has:

• the right size of wires to carry the current and
• the right size of breakers on the main supply panel to protect the air compressor - and the wiring to it - from catching fire if there is ever a malfunction.

Air compressors are quite different to dryers and you have to be sure you wire them up correctly and safely to avoid there being any kind of risk of anyone getting electrocuted.

As you asked this question here, the best advice anyone should give you so you can use your air compressor with no worries is to ask a licensed electrician for his advice. He can also quote you for installation of the correct type of outlet, wiring and breakers on the main supply panel to power your air compressor safely.

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Really, don't do this one yourself. Electricity is far too dangerous to handle if you have not been trained how to do this work. If you put just one wire in the wrong place you risk being killed by electrocution or you could even start a house fire.

How to do this http://jobs.answers.com depends entirely on the Wiring Codes or Regulations for the locality (Town/State) and on the exact location of the appliance you wish to install. If it is anywhere that is subject to water splashes or spray - such as in any room supplied with running water pipes, like a kitchen, bathroom, shower room, etc., or outside in the yard or by a pool-side area - in many places nowadays it is actually illegal to attempt to do this kind of work unless you are already a licensed electrician.

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For more information please see the Related Questionsshown below.

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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS WORK

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.