This weekend, I pulled out our 20+ year old oven to make way for a new free-standing range. The oven was hard wired and there was evidence of shorting within the box. Two wire nuts were completely melted through. Scary.

So I pull everything out, cut off the bad wire, and get ready to rewire an outlet to accommodate the new range which is arriving on Wednesday. However, the wiring is 3 wire, black, white, bare copper. I know this is not uncommon in older houses, but I'm uncertain on how to wire this new receptacle up. I talked to the guys at Lowes, but they don't exactly inspire confidence.

So, I have this receptacle.





And this wire


That is connected to this breaker set. (11-17)


My questions are:
1. How do I wire this receptacle up? The bottom of the receptacle is marked "white wire" where I initially thought the bare wire should go (with white and black to either side).

2. Is this breaker ok? I don't have a lot of confidence in the electrical in this house, and I'm leery of the breaker not tripping when there was an obvious short in the box on the old stove.

[This message has been edited by DevilYack (edited 5/16/2011 8:24a).]

YIKES!!! You are very lucky you didn't burn your house down.

I was going to attempt to provide guidance, but I dont' remember correctly how I did this 18 years ago.

In my experience, (I'm not an electrician) the reason I've seen receptacles or wiring get hot like that is when the romex is the wrong size for the power that's being pushed. I can't tell what size that is, but it looks like it might be 10 ga, which should be appropriate for a 30 amp breaker. It's possible the wiring for the oven was too small a gauge, which could have been the source of the overheating.

[This message has been edited by Ryan the Temp (edited 5/16/2011 8:57a).]

Actually, the most likley culprit was the wire nuts; as you can see from the new receptacle, you need some serious terminals to handle the amperage of an oven. The wire looks to be the correct 6 gauge wire with 10 gauge ground.

Note: You didn't show where this is coming out of the wall. You want to put this in a good, deep housing with a clamp on it. I actually prefer using a 2-gang box instead of a single-gang box so that you have more room to maneuver the wire. Look for one that says "220v rated" or "220v approved"...

Your picture is too blurry for me to be able to see if yours is marked this way, but the one I installed had a VERY TINY "w" and "b" on the proper terminals. Regardless, the white/black will be the "top" two (slanted) and the plain wire will go in the bottom...

Don't forget to put some dielectric grease in there when you screw the terminals down.

Also, the guy at Lowe's was right that it's REALLY not uncommon in not-that-much-older houses. (Unless you're calling me old.)

Don't forget to make the change to your oven (pull out the separating tab) to allow for the three-prong wire kit.

Warning!

Our electrician told us that the new 220's are wired with 4 wires. Make sure you check the specifications of your new stove and that it will work on the old '3 wire'. Some of the fancy electronics require all 4 wires.

Dubi

Agree with dubi. That's why I had to go back and edit my post. I was automatically thinking in 4-wire mode.

I checked the specs for the range and it allows a 3 wire connection.

What is dielectric grease?

There is no box in the wall yet. I'm going to stick a 2gang box in tonight and run the wire through that. The old stove was wired into a closed metal box attached to the stove itself by an armored conduit. Otherwise, the wire just stuck out of a hole in the wall.

I'm still a little nervous about wiring the receptacle. If you look at the picture of the back of the receptacle and see a 'Y', the leg of the 'Y' has "white" printed on it. Based on what I've read online, I don't think I should wire MY white wire into that connector. Instead, I think the white and black wires should go into the arms of the 'Y' and the bare wire should go into the leg. The white and black i have are both hot, but the bare wire is neutral.

The Home Depot boys are going to install the pigtail, so I hope they get it right.

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The oven was hard wired and there was evidence of shorting within the box. Two wire nuts were completely melted through. Scary.

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Was the original hardwired pigtail Aluminum?

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I actually prefer using a 2-gang box instead of a single-gang box so that you have more room to maneuver the wire. Look for one that says "220v rated" or "220v approved"...

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Outlet boxes are not voltage rated, unless you start getting above 600V. The boxes list the available volume in cubic inches. The quantity and size of conductors entering and leaving the box will determine the volume you need moreso than the voltage. However, bigger boxes are much easier to work with when you have to train wires and fit a large receptacle. And technically, your house has 240 not "220" even though it's referred to as such. And the equipment would be listed for 250V.

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I'm still a little nervous about wiring the receptacle. If you look at the picture of the back of the receptacle and see a 'Y', the leg of the 'Y' has "white" printed on it. Based on what I've read online, I don't think I should wire MY white wire into that connector. Instead, I think the white and black wires should go into the arms of the 'Y' and the bare wire should go into the leg. The white and black i have are both hot, but the bare wire is neutral.

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The receptacle in your picture is a NEMA 10-50R, which means it is rated for 50 amps** at 125/250 volts. It is a three-wire non-grounding receptacle. It is intended to have two "hots" and a neutral run to it. In that case, there would be a black, a red, and a white - with the white being the neutral. This is why the "leg" as you described it is marked "white."

In your case, they used plain vanilla NM cable (the trade name is Romex). As you mentioned, your black and whites are the "hots" and the bare is the neutral.

** There's a bit more to it (terminal and temperature ratings), but in basic terms you are going to have a 60 amp circuit breaker protecting a 50 amp receptacle. Think bungee jumping off a 50' cliff with a 60' cord. Will it work? Probably, but I'd consider replacing the circuit breaker.

I've never been a fan of using three-wire receptacles with new appliances where the neutral is bare, but that's me.

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Don't forget to make the change to your oven (pull out the separating tab) to allow for the three-prong wire kit.

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Check the instructions for the oven. When using the three-wire receptacles/cords, there needs to be a neutral-ground bond someplace. On some you pull a tab. Others I've had to install the metal bar.

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Some of the fancy electronics require all 4 wires.

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In the 96 edition, the National Electrical Code was revised to require separate ground and neutral conductors to things like dryers and ovens/ranges. The "fourth" wire is the result of this. In both old and new, the two "hot" conductors provide the 240 volts needed to run the heating elements. In the old, one of the "hot" conductors was tapped and along with the "white" wire (which was a combination neutral and ground) provides the 120 volts needed for the clock/timer/light/etc. In the new, one of the conductors is still tapped, however now there is a dedicated neutral to provide the 120 volts. Same concept, just configured differently.

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The Home Depot boys are going to install the pigtail, so I hope they get it right.

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Based on previous experience with big box stores, good luck with that. Ask them specifically what they are connecting, and why. If you get answers like "that's how we always do it," or "that's how I was taught," push for them to show you how it lines up with what the instructions say. Lowe's installed my SIL's dryer, and the fool insisted they could not cut the dryer vent. He actually installed all 10' of hose all coiled up and crushed behind the the dryer.

Dielectric grease is the pooky that gets squirted into or around electrical connections to help prevent moisture, dirt, or miscellaneous crap from getting in there, or from causing oxidation. You'll see it quite a bit in taillights and turn signals. I'd be more concerned with applying anti-oxidation compounds if you had aluminum wiring since AL oxide is resistive. Copper oxide remains conductive.

NVM, those are stab in. The connections need to be tight.

[This message has been edited by UnderoosAg (edited 5/16/2011 7:48p).]

I agree with UnderoosAg. I would be very uncomfortable using the bare copper as the neutral lead. You would have current running through the bare copper. It should work (turn the stove on) but I think it completely gets rid of the protection the ground wire serves.

I can imagine a bunch of unlikely situations where it will cause shock or a fire. They are unlikely but a concern enough to be put into the electric code.

Yeah, I'm not wild about it either. I've considered rewiring the whole circuit, but I'm unsure of my ability to do it safely. Frankly, electricity scares the crap out of me.

This house is wired funny anyway. I moved the electrical outlet for the microwave and found that a string of outlets on the kitchen counters is wired together. That's not strange. Finding out that TWO circuits are feeding electricity to the one string is weird. And almost killed me. Luckily I'm so paranoid about getting shocked that I test every wire before I touch it.

Maybe I should just suck it up and call in a pro.

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Finding out that TWO circuits are feeding electricity to the one string is weird. And almost killed me. Luckily I'm so paranoid about getting shocked that I test every wire before I touch it.

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Yeah, that is weird. I've run into it before, though, usually where some bonehead did some renovations and didn't bother to figure out what they're doing. Check to see if one of the circuits is the one your GFCIs run on ...

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Underoos, thanks, you filled in a ton of blank spots in my knowledge. I know just enough about electricity to not kill myself, not set the house on fire, and pass inspections. I'm basically an unsupervised apprentice, but I do better work than many pros I've seen working on tract homes...

I installed a gas oven that has a 110 + gas, and put the 220 receptacle in behind it, but I taped up a warning above it saying that it was "old wiring" and probably shouldn't be used. If anyone replaces the stove in the future and decides to go electric instead of gas for some ungodly reason, they can mess with re-wiring it.

DevilYack, price the wire for the home run to your panel before you consider rerunning the whole circuit. 3/6+1 is expensive stuff. OTOH, it's way cheaper than a house fire, which is why the code got changed.

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It should work (turn the stove on) but I think it completely gets rid of the protection the ground wire serves.

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The oven has essentially been working thus far using the bare as the neutral. Assuming of course, it is actually connected as a neutral and not as a ground. It doesn't completely remove the ground from the equation, there are just better ways to do it. The point of the ground is to provide a clear path for fault current. If something gets caddywhompus in the oven/dryer/refrigerator/margarita machine and the case/frame/switch/lever becomes energized, you want a clear path in place such that fault current will flow, trip the breaker, and clear the fault. Tis far better for that to happen over a wire than across Devil Yack or Mrs. Devil Yack, for example. The combination ground/neutral or "grounding thru the neutral" as it were called works, kinda sorta, but again, there are better ways to do that. And yes, there is the potential (no pun intended) for current in the neutral wire which is bare.

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This house is wired funny anyway. I moved the electrical outlet for the microwave and found that a string of outlets on the kitchen counters is wired together. That's not strange. Finding out that TWO circuits are feeding electricity to the one string is weird. And almost killed me.

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It's called a multiwire circuit. You have two "hot" conductors from two separate circuit breakers feeding two branch circuits or "strings" of receptacles. The two circuits share a neutral. The NEC requires two small appliance branch circuits in the kitchen, so you can open the chili while microwaving the velveeta. The multiwire circuit allows you to use one three conductor cable to wire both circuits. It works, until you do anything that requires disconnecting one of the wires. The voltage from either hot to the neutral is 120V. The voltage between the two hots is 240V. If you lose the neutral, there are scenarios where you could actually put 240V to your receptacles. Or, what probably got you, was shutting off one circuit breaker thinking it was de-energized, and then finding out the hard way there was a second one. It's called Shaking Hands with God.

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Luckily I'm so paranoid about getting shocked that I test every wire before I touch it.

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That's not being paranoid, that's taking your work seriously and being careful. Absolutely nothing wrong with that. Stick voltage detectors are made for a reason. Billy Badass electrician who says, "don't be a pansy, it's only 120" aren't the guys you want to work with. I know one who owes his life to an AED and a coworker who knew how to use it.

6/3 NM cable with ground is probably $2ish per foot. You have a 50 amp receptacle. If your new oven only requires a 50 amp circuit, you can use 8/3 with ground. A little bit cheaper, but then the circuit breaker should also be changed.

Make sure you get the 6/3 or 8/3 from an electrical supply; you won't get that price at Lowe's or HD. I think when I priced it, it was closer to $3.50/ft at Lowe's.

New range was delivered and installed yesterday. The house has not burned down and the range works, so I guess I did it right.

I think I'll wind up replacing the 60amp breaker with a 50amp, but leave the 3 wire in place. I'll let y'all know how that goes.

Thanks for the advice.