I've run new wire out to my garage for a 240v 30amp outlet for a welder. The outlet for the welder is a
3-wire outlet and the 10 awg wire that I ran has four wires (bare ground, black, red, white).
I connected the red and black wires to the breaker, the white to the neutral bar in the sub-panel, and the ground wire to the ground bar (separate from the neutral bar).
So, if I want to use this wire, should I just clip the white wires off at both ends? I've checked all of my wiring books and I can't find a good answer to this question.
Don't clip it off; just tape up the white wire at the garage end. You may want to split that 30A circuit some day to run a big 110V load (a table saw?), and you'd need a neutral wire to do it.
Ageed! Rule of thumb with wire: Never cut off what you (or the next guy) might need some day.
To be extra-double-dog-super-duper cautious: put a black wire nut on each end of the white wire. (DON'T strip the wire first, so it's thick enough to hold the wire nut)
Yep. He could have half-assed it, like a plumber/HVAC guy would.
And then someday when he wants to change to or add 120VAC outlets to the circuit, he could thank himself for saving $4.00 on the wire as he opens up the wall to change it out.
Of course we all know that the welder belongs on a circuit by itself, and one has no business whatever hooking up 110v outlets to that circuit. I am curious as to why the welder only needs a 30A circuit--mine requires 50A, and it is not that much of a welder--Lincoln 225A.
With a 4-wire feed, he could later add a little subpanel. Put the welder on a 2-pole breaker (or fuses) and a 110V circuit on a different breaker (fuse). You wouldn't run the welder at the same time as anything else in the panel.
A fused switch with a couple of edison fuses in the cabinet would be really handy if it has lugs between the switch and the fuses. Run the welder outlet off the switched lugs and a couple of outlets off 20A fuses. The switch would disconnect power to everything and could be locked to keep kids out of it. The 30A-2P breaker in the house would provide overcurrent protection for the welder. The fuses would proved overcurrent protection to the outlets.
I don't know what kind of welder only needs 30A; maybe it has a low open circuit voltage, or maybe it is only 170A. Or maybe a really nice wire-feed welder. It didn't seem to matter.
Depends on the output, I have connected Lincolns at 30, 50 and 100 single and 3 phase. Millers at 20,30 and 50 all single phase. And I have 2 wire feeds that run on 120.
It's my understanding of this kind of thing that you hook the white and the ground both to the neutral bar in circuit breaker box. On the other end of the wire, hook both to the ground terminal of the socket. Good to have the same ammount of neutral/ground (two wires) as what you have for power wires going out to the socket.
While on a pure 240V device (like a welder or 240V heater), all you're doing is doubling up the ground wire (which isn't a _bad_ thing), there are other issues to consider:
1) If this is fed from a subpanel (separate ground and neutral) this violates code for neutral-ground interconnects. The only exceptions to this were
240V/120V connections to stoves and dryers on three wire circuits (fed from main panels _only_), but this is no longer permitted in US code (illegal by Canadian code for several decades). The only place where white and ground are connected together is in the main panel, and homeowners generally don't diddle with that very often.
2) It's code-illegal simply by virtue of the colour code - white is for the neutral, _not_ ground - grounding wires have to be bare or green.
3) There are some (albeit very unusual) fault conditions that doing this would make quite dangerous. Yes, extremely unlikely, but wholly unnecessary - no advantage is gained by doing this.
The very best thing to do, since the wire is already paid for and laid, is what the others have suggested - simply cap off the white wire at both ends (don't cut it short) and don't use it at all. [You could probably get away with leaving the panel end connected, but an inspector may get picky about "unused but connected" wiring.]
This provides maximum flexibility and ease if the OP's (or subsequent buyer's) requirements change, and may, for example, consider converting the circuit to a small subpanel feed with branch circuits of 120V or 240V (or both) or something else (like another dryer) without having to pull new wire or change breakers.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.