A few years back I had a 240v outlet installed for a kiln. The
kiln and the outlet are both 3-prong. It was removed in recent
construction and I have to reconnect the receptacle. The wire
(both before and now) as 3 conductors (red-black-white) plus
a bare copper ground. The receptacle has 3 wiring spots, one
labeled ground. On my box I believe that the white and bare
ground go to the same breaker bar. Which wire (or both?) gets
connected to the ground lug on the receptacle? I’m guessing
that the black/red go to the other 2 places and are interchangeable. Wish I had been the one to disconnect it
originally. Probably a stupid question, but I’d appreciate any
help you can give.
Thanks
glenn
Replies
Assuming the receptacle is correct for the kiln and the kiln really is 240v without any 120v controls the usual arrangement would be for the hots, the black and red wires to hook to brass colored screws and the bare or green wire to connect to the ground screw. Which would likely be green and possibly hex shaped.
In that case it won't matter which hot conductor, red or black, gets connected to which brass or, otherwise identified by the word hot beside it, screw. If the receptacle, and so presumably the kiln, doesn't have any need for 120v the white wire can be capped off, a wirenut or a few wraps of tape will do, and tucked neatly in the back of the box.
Whatever you do, don't cut the white wire short. It'll come in real handy down the road if you ever want to convert that outlet to a 4-prong outlet.
Yes. Absolutely correct.In most cases unneeded conductors are better off capped and tucked in neatly than cut off short. If the needs change, like a new kiln with 120v controls, that white wire will eliminate the need to run a new cable. Similarly if something goes wrong and the cable is damaged the unused conductor could save the day. Having a spare is a good thing.
Thanks for the wiring help. Good advice.g