Wiring a compressor for 220v ?

[TDKPE]

Can you even buy a 110v 4 hp motor? Unless it is a crapsman using their inflated and inaccurate HP claims I cannot say I have seen one on a compressor

I wasn't paying attention to the actual question.  Or the setup, for that matter. 
  I read what I was expecting the question to be, rather than what it actually was.  


You can get 3 hp in 115/230V or 115/208V flavors, but I don't know about 4 hp, especially since it's not a NEMA standard size.  Never seen a 5 hp in 115V.

[Gregory of Sherwood Forest]

Thanks guys, I appreciate the help. I decided to go out and buy a proper cord, one that is made for this outlet and is a solid piece construction with heavier insulation. All I have to do is connect the wires in the switch. I'll be putting both the neutral and the ground on the ground connection. I was able to get the cord for just $6 after taking back the plug I had. I think it was worth the extra, if only for the strength and it will also keep sawdust off the internal connectors of the plug. The first one I had wasn't well sealed.

Chuck S. happened to stop by the store today, so I asked him what he recommends. He agrees that the way it was wired would work fine, but he agreed that the better plug is the best solution. He gave me a 5 minute lesson on wiring 220v, too. I feel more comfortable after his advice and all the advice I received here.

Thanks again, guys. I appreciate it.

[TDKPE]

I didn't notice it before, but you were using the neutral prong as an equipment ground, which isn't correct.  Since you're changing to a 4-prong plug, just use the equipment ground, and leave the neutral disconnected.  If you connect them at the equipment, you'll get current flowing on the equipment ground, with the amount depending on how the building is wired (subpanel, for instance) and what load is on the neutral pole it's connected to.

[Gregory of Sherwood Forest]

Okay, I bought the new molded plug. It has 4 leads. The 2 hots are obvious. Now, I was told to put both the neutral and the ground wires from the plug on the single ground pole in the switch on the compressor.

IS THIS CORRECT?

[blackhat]

No  2 hots and ground are connected.  The white wire (neutral ) in the cord is not connected to the machine.  Cut any exposed wire off, flush to the insulation and then wrap it with tape leaving it loose in the junction box.

[Roly]

Suggest checking the receptacle. The older dryer circuits used the neutral as a ground. Make sure the receptacle has both a neutral and a ground if it was replaced. Roly

[Gregory of Sherwood Forest]

ROLY, I'm installing the 220v circuit also. It has both a neutral and ground.

Thanks Blackhat. I'll tape off the neutral and use the ground and 2 hots. I'm going to feel much better using this molded plug.

[Rob Young]

I don't have a clue who Chuck S is, but if he knows how to do this safely and correctly, he should come over. Improperly wired anything that causes a fire, also generally waives your insurance if it is found to be the cause of the fire. Last I read statistics, poorly run electric is still the leading cause of home fires. Not saying guys here don't know how, just saying they aren't there, and electrical work is hands on stuff.

Chuck S. is a local woodworker (KC Woodworkers' Guild) that both Greg and I know and he also enjoys machine restoration.  The big arn stuff, stuff that was originally designed for overhead shafts but now needs to be converted to electric.  He's done a lot of work with 220V and three phase wiring and has received training too.  Generally has a good grip on the situation.  He only twitches a little bit now.

Good to see he stopped by Metro and that Greg could pick his brain.

[Stwood_]

   He only twitches a little bit now.

Must be the dude I met at the breakfast. He was twitching and giving me the evil eye.


Yea he had a grip on me, shaking hands.

[Rob Young]

Must be the dude I met at the breakfast. He was twitching and giving me the evil eye.


Yea he had a grip on me, shaking hands.

Yep.  He's a big boy, ain't he?  He does tend to look pissed off most of the time but that's just his resting person-face.