220 volt to 110 volt


Old 08-06-05, 02:25 PM
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220 volt to 110 volt

An electrician ran an old stove circuit 220 volt, 3-wire, (8 or 10 gauge I believe) to my microwave location (we did some relocating and remodeling in the kitchen).

I plan on pulling the double pole breaker for this circuit and installing the correct amperage (15 amps I think) breaker for the microwave for its own dedicated circuit.

Then use the extra bay for a dedicated circuit to power a new whirlpool tub I put in. I already have 12 gauge romex for this circuit run into the breaker box. (No open bays in the breaker box).

1. Any concerns you guys see with any of this?

2. Also, Is it ok to extend the length of the thick gauged (now the microwave) circuit with some 12 gauge just using a wire nut, inside the microwave outlet box? So the wires will fit the outlet. This is what is normally done?

3. And, if I am only going to be using only one of the hot wires of the 220 volt, 3-wire circuit to the microwave, I will have the other hot wire hanging loose in the microwave outlet box and in the breaker panel. What should I do to note this for later on down the road for a new owner and what does code say to do with this wire that is not connected to anything?

4. One more thing, the electricians, in the attic, just ran the romex over the tops of the ceiling joists. This is not code is it?
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Old 08-06-05, 05:21 PM
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You say this circuit is three wire. Does it have a ground? If it has no ground then you cannot (and should not) use it. If it has a ground (along with the other three wires) then you can use it.

You would cap off the unused hot wire with a wire nut at each end.

You would use pigtails at the receptacle to make the connection.

Use a 20 amp breaker.

Finished attic? Unfinished attic? Partially finished?
Old 08-06-05, 05:39 PM
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You say this circuit is three wire. Does it have a ground?

Sorry, I guess you guys are very right not to make assumptions on this site. It is grounded. Next time I will include this.

Finished attic? Unfinished attic? Partially finished?

Totally unfinished and never will be - it is too short to stand up in.

Old 08-06-05, 08:18 PM
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The rules are a bit complex for attic wiring, but running Romex over the tops of the joists is usually just fine.

Please give us the exact number and colors of the wires in the old stove circuit. We still don't yet have enough information to rule on this.
Old 08-07-05, 12:03 AM
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Uh oh, I made a mistake.

This is actually at my dad's house so I was not able to actually look at it. I was assuming. I called him tonight and had him look. There is only 2 hot and a neutral. John Nelson you are sharp!

2 Hot: red & black
1 Neutral: white

This is wiring from about 1950 - the black woven kind with paper insulation. I do not know why the electrician kept this if he knew there was no ground. There is no ground to the dryer circuit or the water heater either.

The funny thing is that my dad had a fire and it damaged one part of the house (not the kitchen). However, it did damage the dryer and the water heater and they are being replaced. (The house is just getting finished up). He decided to re-do some of the kitchen since all this dust was floating around anyways.

So now that gets me thinking why wouldn't the insurance have had these wires to the water heater and dryer replaced with a grounded wire since the appliances had to be replaced (even though the wires weren't damaged). I read on here somewhere how you need a permit even to replace a water heater. And since they had to be replaced wouldn't new wiring be needed to be in compliance, not to mention for safety's sake. Plus a lot of the walls and ceiling were open for new sheetrock and it would have been easier; hell, the whole breaker panel has been replaced too! It was damaged in the fire.

Anyway, the electricians who did the kitchen also had first worked on the part of the house that was burned - a family room (converted garage). They replaced some damaged wiring here. This part had already been completed with a permit.

After this was done (weeks later) my dad decided to re-do the kitchen (not part of the insurance). So we tore out a wall between the kitchen and the dining room and this is where the wire in question came from. In fact there were a few wires. He called these same guys back to fanagle these wires. They were first going to pull a new permit but then their boss (owner of electric business) said they did not need to.

So this is the long journey that the old stove wire took to become a wire to the now microwave above the now oven/cook top. Come to think of it I don't believe the circuit to the oven has a ground either - it is already hooked up. They ran that line from the same demolished wall. There were two 220 volt circuits on that demolished wall. Was that right to do?

And on the microwave, could they have intended using one of the hots as a ground? This does not seem like a good idea to me - it might confuse someone later on down the road.

So now what do you guys think?

The good thing is all the 15 and 20 amp (110 volt) circuits are ground (I guess some really old houses don't have any ground). But why did they not ground the 220 volt circuits?

Last edited by sparky23; 08-07-05 at 02:23 AM.
Old 08-07-05, 05:58 AM
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You do not have a ground. You cannot use this circuit for 120. Leave it alone, and install a new 120 volt 20 amp circuit.

Old wiring is grandfathered. You are allowed to replace an electric range and/or an electric dryer that is run with three wire (no ground) cable. You cannot install a completely new installation this way, but you can replace an existing device.
Old 08-07-05, 04:05 PM
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Why would a licensed electrician rough in this wire this way if it is non-code?
Old 08-07-05, 05:45 PM
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1) That old wire was installed 'to code' at the time that it was installed. This is because it used to be permissible to ground the frame of a range (or electric clothes dryer) using the neutral. This is no longer the case.

2) If the electrician simply left the old wire in place to remain an electric range receptacle, then it would still be 'to code' because of the grandfathering that Racraft mentioned. A modern 120/240V circuit requires 4 separate copper conductors; 2 hot (usually colored red and black), 1 neutral (colored white) and 1 ground (bare or green)

3) If the electrician moved this old wire to a new box with the explicit intent that it become a 'new' 120V circuit, then it is no longer grandfathered. This installation would not be 'to code'.

A modern 120V circuit requires 3 separate conductors, 1 hot (black), 1 neutral (white), 1 ground (green or bare). Now, you happen to actually have 3 conductors, so using this wire you could actually connect this receptacle with _all_ of the electrical safety expected with modern code. The issue is with the color code _only_.

But this is a very real issue, because if, for example, the electrician used tape to 're-code' the red wire as your equipment ground, then someone else working on the circuit could in error connect this 'ground' to a circuit breaker, energizing the outside of the microwave. Not very safe.

250.119(B) _Explicitly_ permits this sort of 're-coding' of wires for use as grounds, but only 'where conditions of maintenance and supervision ensure that only qualified persons service the installation', eg. in an industrial plant with on site electricians. My guess is that the electrician thought that this recoding was appropriate in a home...people make mistakes.

Old 08-08-05, 01:58 PM
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i am a bit confused as to waht counts as a proper ground. if all the boxes in the walls are metal, and they are all supplied with armored cable throughout the house, would that count as properly grounded because the armored sheath is the ground?

and would I be able to ground boxes to the plumbing pipes if the above method is not proper?

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