Old 220V Compressor... no ground?

[jeffesonm]

I am hooking up an old (1957) Quincy air compressor I bought off craigslist. The tank was rusty and had water inside, so I got a newer one a buddy had lying around in his garage. Water pressure tested it up to 200 psi so good to go there.

Now I am wiring the thing up. It has the biggest 2 hp motor I've ever seen... can be wired either 110 or 220, and was 220 before so I'm keeping it that way. It will live just outside the garage under an overhang so I ran a 10 awg circuit from the garage subpanel to an AC disconnect box mounted on the outside wall, and then liquid tight to the motor.

Except there's no ground. Just two hots for the 220v. No ground screw I can see anywhere on the motor. What do I do with the ground? Throw a wire nut on it and call it a day?

 

[seige101]

Definitely ground it! You might have to get creative like drill and tap somewhere for a screw or ground the outside frame of the motor some how

 

[Dr.Faustus]

does it say double insulated anywhere on the motor? some tools I have I noticed there was never a ground on the plug, but the tool says "double insulated"
well once day out of curiosity i looked this up. i found:
"Class II or double insulated tool is one which has been designed in such a way that it does not require a safety connection to ground."


hope this helps

 

[jeffesonm]

It does not say ... I just screwed it into one of existing screws on the motor. It's now compressing air and so far, no electrocution! Yay!

I've got an ever so slight leak somewhere I need to track down and them maybe build a little cover for the compressor and motor. They are under an overhang but still catch some rain when it goes sideways.

 

[DougA]

I would weld, clamp or drill a ground onto the unit somewhere. The unit is pretty old and can't be double insulated, that's too modern and 120v as far as I have ever seen. Double hot is all it needs but a ground is for safety - your safety.

 

[semipro]

Is that a flex connection between the compressor and tank?
If not, given the compressor and tank are mounted on different bases, I'd be worried about fatigue and eventual breaking of a rigid connection.

As you mentioned a rain cover I'd make darned sure no rain can make its way into the air intake. Trying to compress a liquid is a sure way to ruin a compressor.

 

[jeffesonm]

Yes that is a little flex section in between. Good point on the rain.

 

[blades]

Just to clarify, Are you using the conduit as the neutral, + your 2 hots, Then your "Earth" ground ( sometimes not even installed), that was the conventional way back in the day- not code now.

 

[jeffesonm]

No neutral... just two hots and [earth] ground. My understanding was you only need 4 wire if the appliance had both 220 and 110 features like a fancy oven or something.