Wiring Older Mill
Hi, I have an older Mill running on single phase 220v. It had a "work light" wired to one leg of the 220v (110v) with the return or "neutral" for the work light connected to the body of the machine. The body of the machine is in turn connected to the neutral wire in the outlet and on to the neutral bar in the main service box. This is a 3 wire 220 mill and is connected to a 3 wire 220 circuit with 2 hot legs and one neutral...no bare wire ground at all.
I was uncomfortable with this wiring and have removed the "work light" so now the 2 hot legs go to the motor and the return leg ties all the chassis parts together as a normal ground would.
My question is should the return leg be moved to the ground bus bar in the main pannel or can it stay wired to the neutral bus bar? The neutral and ground bars are tied together in the box so it seems an unneeded expense to get an electrician out to do this.
Thanks for your thoughts....
Do you have metallic conduit to the machine?
A viable ground path to the case ground on the panel?
You need a isolated and clean ground on the machine. THE old refrigarators had a hot neutral ground. If you touched a water spickot in the kitchen you made a better ground then the copper return wire. It'd shock you silly.
Is the green bonding screw from the neutral bar to the case ground inside the electrical panel? If so the ground bar is at the same potential as the neutral bar. Most inspectors won't allow the green screw to be in there.
You can tie wrap a saftey ground on the outside of the Romex? if you have it wired with house wiring, hook the light back up to the neutral and off you go safe and lit.
The proper way, is to use a 220/120 transformer or provide proper hot-hot-neutral-ground wiring and appropriate fuse protection for the light.