I have an older 220v wire with only 3 wires... 2 hot and 1 ground/neutral (bare). I need to connect (splice) it to a newer 220v wire with 4 wires... 2 hot, 1 neutral (white), and a ground (bare).

And older I mean less than 15 years old.

tkrussell

So what kind of cables do you have? Probably the old one is BX, withthe metal outer sheathing. If this is the case, the metal sheathing is the "fourth" wire, serving as the equipment ground. The new cable is probably Romex, with the bare equipment ground.

You must use a metal junction box, you need to use an approved connector for the BX cable, and wrench tight the locknut onto the box. The bare wire from the other cable can be connected to the metal box using a machine screw into a threaded hole you will find in the back of the box. This is an approved method to connect the two equipment grounds from each cable together.

Do not forget to install a box cover once you are done splicing.

PalmMP3

TK,

Are you sire he isn't referring to an appliance cord (e.g. a three-wire dryer cable that he is trying to tie into a four-wire line)?

Either way, it doesn't sound to me like his "older" cable is BX - he says "I have an older 220v wire with only 3 wires... 2 hot and 1 ground/neutral (bare)" - so he's obviously seeing a bare wire somewhere, not BX armor...

Cheers,
Moishe

tkrussell

I see your point, I did not pick up that the cable being refered to is SEU cable, two insulated hot wires, with the bare wrapped around the outside of the hots.

Got in late after a long day of electrical work. Sometimes the brain does bnot jive with the eyes.

In this case the 3 wire cable should be replaced with 4 wire, to extend the equipment ground back to the panel. This is probably for a dryer or a range, which now require 4 wire, and there is no other alternative to connecting the ground.

Good catch.

tstevens83

Thanks for the info... I did replace the old wire with a new 4-wire... 75ft of wire. Boy that wire has a mind of its own.

It was for a range. I'm now looking at moving a dryer... hope I don't find the same situation.

Bob V

I am also facing this dillemna - connecting an old 3-wire 220, extending it with a 4-wire. The solution given me by an experience electrician is simply to ground the new green wire to a copper plumbing pipe near the junction box and run the new 4 wire 220 cable back to the panel.

stanfortyman

Well, Bob, your "experience electrician" is a hack. It has been MANY years since it was legal (or safe) to ground to a local water pipe. They realize how dangerous this could be and dropped that allowance. This is especially true with the boom of Pex and cpvc piping being used.

I am confused, you say you are extending the old three wire cable, yet you say you will run the four wire cable back to the panel.
WHAT exactly are you doing?

I can say with certainty. You CANNOT extend an old 3-wire range circuit. Period.
You MUST run a new 4-wire circuit back to the panel.

Bob V

Stan, thanks for your reply. The situation is an old home built probably in the late 40's or 50s. The kitchen is being remodeled, all the sheetrock removed making it possible to strip out all of the asbestos insulated wire, replacing it with Romex. None of the original circuits will be used. They will be disconnected and capped at the panel. This is where the old 3-wire 220 comes in. It serviced the original electric range but now a gas range will be installed. The breaker panel is an old pushbutton type and unfortunately located at the far end of the home in the basement where it would be impossible to run a new 4-wire cable without a lot of tearout. Plan is to junction that old 220 with a 4-wire cable and run it to a new subpanel in the kitchen which would service new circuits throughout the kitchen. The new 4-wire cable would be grounded to a copper pipe. The original breaker panel is grounded to the pipe where it comes into the house, rather than spikes driven into the dirt, as seems to be the practice now. The electrician in question has 50 years experience, has taught IBEW courses, has owned his company since the 50s and is up on the '08 codes. He knows this isn't exactly legal but doable in light of the situation and budget.

stanfortyman

Knowing what type of cable they used back then it is HIGHLY likely this would not be a legal or safe thing to do. You DO need a 4-wire feeder to a sub-panel.



NO, it should not! From a legal and safety standpoint.
As I said, this was legal back in 1975, but they soon realized how dangerous this could be.
The piping in a house SHOULD NOT be used as an equipment grounding conductor.
The ONLY time this is safe is IF: a) the water pipe in question is being used as a grounding electrode, and b) you connect your ground within 5' of where the pipe enters the house.
Tell you electrician friend to look up 215.6 Feeder Conductor Grounding Means, 250.134 and 250.130(C).



The practice of using a metallic water pipe as the primary electrode has been around for many years. Newer codes require a supplemental electrode (or two) be installed as well.



Sometimes some of the old timers make the worst mistakes.
"Doable"??? Budget??? I hate being so harsh, but if your guy would do this he truly is a fool and doesn't value his reputation or your lives very much.

Please have him read those sections I mentioned to show how this is not so "doable".

donf

HI guys,

T Steven's did you bother to check for the amperage needed by the new equipment? Were the amperage levels the same?