220v wiring question

OK, muddled through my 1987 copy of the National Electric Code and surmised that I can hook up my wife's three electric kilns (since there is no 120
volt component in the kilns) by running only three wires. 2 hot leads and one neutral. These three wires come from a secondary panel that has both neutral and ground. One panel back, is the main panel where the neutral and ground are bonded together. Question: As long as I am doing this, I would like to drop of a fourth outlet, should I ever need to use my welder at this location of the shop. I have an old Miller TIG and an old Solar MIG. The leads on these machines are 50 amp three wire. Should I be bringing over a ground wire from the panel for the welders? What do I do with this "fourth" wire? The receptacles and welder plugs only have three wires? Is the neutral wire sufficient to serve as ground? etc.
BTW, I ran #4 awg to these outlets. I know it's overkill, but, found 3 - 75 ft. brand new pieces at a garage sale for only $ 4.00.
Please help with my confusion!!
Ivan Vegvary
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If your welders have only three wires, I am pretty sure they are two hots and a ground.
I expect your wifes kilns are the same way. Two hots and a ground. Not two hots and a neutral.
To check look and see where the ground or neutral connects on the kilns and welders. If it connects to the chassis, it is a ground. If it connects with a path to one of the hot wires, it is a neutral.
Dan
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If you have 4 wires(single phase), it is 2 hots, neutral and ground. Neutral should NOT be used as a ground. Yes, it is theoretically the "same", but the ground is intended to a redundancy and would present a safety issue if it ever failed.
If you are not using 120, then there is no need for the neutral(your 4th wire).
As for overwiring, the only reason not to use big(ger) wire is expense and hassle of handling it. On longer runs it is recommended to upsize at least one(1) size. For what you paid, it's a no brainer to overkill it a little.
JW
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You should be saying "two hots and a ground" not neutral.
Jim
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I would find it rather unbelievable that welders do not have a ground.
i

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Note: I'm not an electrician. However, I have recently reviewed the 2002 NEC, since I am working on a major home project that involves a lot of 240V wiring. Yes, I pulled a permit, it will be inspected soon.
On Mon, 20 Jun 2005 16:43:52 +0000, Ivan Vegvary wrote:

It's 2 hot wires and ground, not neutral. Even though they're bonded at the main panel, they are different. Neutral is meant to carry current in normal use, ground is not. Ground is always bonded to the frame, neutral is not in new wiring.
So for the kilns, you are good with three wires - two hot, one ground.

Double check that the welders don't have a 120V fan motor. If there is no 120V component, then you do not use a neutral wire. The welders must be grounded with the GROUND wire. You cannot use the neutral for grounding.
If there are 120V components in the welders, you might need to re-wire them so that ground and neutral are separated (4 wires - 2 hot, 1 neutral, 1 ground). As best as I understand it, there is no exception in the NEC for old welders, only dryers and ranges on existing wiring. Since you're running new wiring, you can't legally ground the welder frame through the neutral wire. I could very well be wrong on this, you should check with your local inspector.
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Please for your sake and the sake of others learn the difference between "ground" and "neutral". For simplicity look at it hs way. Neutral is normally a current carrying conductor. Ground is like the safety chains when pulling a trailer. Rarely used but there in case things go wrong. And if things do go round find out why, correct the condition and start again.
The neutral is connected to the ground system at one point. This is a safety measue to keep the system from floating more than the potential of the line voltages. In this case 110 and 220. Single point connection also minimizes ground loops to just one which are killers for electronic equipment. Bob AZ
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