how do you ground an ungrounded electric motor?

[v7guy]

Tried to change title cause it's inaccurate...
I have an old washing machine motor that powers my lathe that needed the cord replaced on it. I bought a replacement cord but there's no provision for the third wire (neutral) on the motor, just power and ground. Is there a proper way to hook it up or do I just leave the third wire unconnected after taping it off?
I looked online and searched here and couldn't find an answer.

 

[Socophreak]

Wouldn't there be provision for neutral but not ground?

You should just be able to ground right to the motor's case where it won't interfere with the motor physics and equipment operation.

 

[v7guy]

I probably have the terms mixed up. I'm no electrician. I spend too much time working on 12v and I end up having to re read the wiring basics every time i start a new household wiring project to make sure i do it correctly.

So usually in this case you would just drill, tap and fasten the third wire to the case that way?
Would there be anything wrong with using an existing bolt that bolts the case together?

 

[jtbinvalrico]

I would think that would be fine. What you are trying to do is give the electricity someplace to go in the event that the motor case becomes energized by an errant wire or short. That's a layman's take on it......maybe a pro will chime in on it.

 

[Gregishome]

Any metal connection for equipment grounding on the motor will work as long as the connection is not subject to physical damage, exposed to shorting out any motor lead connections, clean of paint and has a green conductor .

 

[superdel]

Sometimes the motor has a peckerhead where you connect the hot and neutral with wire nuts. This is fastened to the motor with a bolt of screw. Crimp on a spade lug on the ground wire and fasten it to this bolt. If the motor is mounted to the lathe by a base, you can fasten the lug to one of the bolts holding the motor to the lathe. If there is a fan on the end of the motor, one of the screws holding the end bell on will do the job as well.

 

[Speedy Petey]

Sometimes the motor has a peckerhead where you connect the hot and neutral with wire nuts.

Just for clarification, a "peckerhead" is a splice box mounted to the outside of a motor.

 

[Gregishome]

Just for clarification, a "peckerhead" is a splice box mounted to the outside of a motor.

I know a few people that must have motors inside of them then.

 

[kbs2244]

If you are a 12VDC guy you have to learn the 120VAC terms.
Black is the "hot" Supply.
White is the "netural" return for the juice supplied by the black.
Green is the safty "ground."
The green should not be carrying any juice.
It is there as a safty back up to the white.

In your case the black and white from your new cord should go to the motor terminals and the green ground to something like the motor case or mounting bolts.

 

[BFBOB]

By code, (no, I can't quote chapter and verse) the ground connector must have no other purpose. That's why j boxes have a separate screw for the ground wire attachment; you don't just use one of the cover screws. So, drill and tap or use a scrw and nut, somewhere on the motor's frame to attach your ground lead.
Oh, yeah, the grond screw is supposed to be green too.

 

[superdel]

BFBOB is correct about the code. However in my defense, using the cover screw or something else, will keep you safe. You should always do things to code. Safe is not always code compliant.
(Off the record, if you are not having an inspector come in, then do what you want. But please, above all, even if you do something that is not up to code, understand what you are doing and make sure you and your equipment are safe.) There are many well meaning and knowledgable people who post on this forum. Before taking anyone's advice, make sure you understand it fully and ask many questions until you do.

 

[v7guy]

I ended up putting the green wire to the case with an existing bolt. It started the Lathe right up. Thanks for taking the time to reply guys!

 

[sberry]

It is there as a safty back up to the white.

Not exactly, the white is a current carrying grounded conductor, the green is a fault return.