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Kevin, Master Electrician
Category: Electrical
Satisfied Customers: 259
Experience:  15 yrs field experience with 11 yrs as self-employed contractor specializing in home repair\upgrades
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Wiring a 220V wall oven. Wires are red,black,white, ground

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Wiring a 220V wall oven. Wires are red,black,white, ground and wired as per instructions with matching junction box 10/3 30 amp circuit. Oven will not turn on broil element and bake function seems to be at half operation and takes a long time to heat up. My question is whether I have the breaker in the fuse panel out of phase? I know the panel is paired. My cook top has only 3 wires, red, black, green and the neutral is marretted off. There we had to move the breaker down one slot so the phase worked properly. Is this the case with the oven or could the unit just be faulty?
Submitted: 7 years ago.
Category: Electrical
Expert:  Kevin replied 7 years ago.
I am assuming you have a 3 phase service coming in to the house if you are concerned about phasing, correct me if this is not the case. You may have a high leg service, meaning the center phase of your breaker box has a higher voltage. It's not that common, but they are out there. When you said you had to "move the breaker down" did you install the breaker on the high phase, and then turn on the breaker? If so, this may have burnt out the circuit board in the cooktop.
Customer: replied 7 years ago.
No. The cooktop works just fine when it was moved down one notch. In the cooktop case the neutral is not in use. My problem is with the wall oven that is using all four wires. My question is in relation to how the 30 amp breaker is installed. In the correct phase? It is installed in exactly the same way as the 220V dryer which works. So I am guessing it may be a fault with the oven itself.
Expert:  Kevin replied 7 years ago.
If you have a single phase panel, in other words, two hots coming in from the meter. Then it doesn't matter which phases the oven is on. If it is a 3 phase service, or 3 hots coming in, it still won't matter unless you have a high leg service, in which case, the oven can not be connected to the high leg phase.
Customer: replied 7 years ago.
So if all the lights and dials work on the wall oven and fan kicks in as it is a convection oven I am getting at least 110 power. Since the broil element doesn't work at all and the bake function seams to working at half strength it may be an internal wiring issue that causes the oven not to get full 220 power?
Expert:  Kevin replied 7 years ago.
Very likely. Now I am also assuming this is on a seperate circuit from the cooktop as it should be. If you have a full 220 volts between the hots on the wire coming from the breaker box, and the oven doesn't require more than 30 amps, which is unlikely, then it is most likely a problem with the oven itself. Also be sure about the high leg situation. Your meter may read 208-220 volts, but you may still have the breaker on a high leg phase. The key there is to check each phase to ground, making sure it is only 110-120 volts on each of the hot wires. If all this is in order, then I am thinking you have yourself a faulty oven.
Customer: replied 7 years ago.
Yes, Two separate 30 amp circuits for the cooktop and wall oven. The new fuse panel is a 60 amp service with it's own breaker. We replaced the old one in this condo as it only had a on/off in the electrical room. Now we can turn it off in the suite and work on things if required and not need a key to get into the electrical room.

I will call a service repair under warranty and hopefully they can acertain the problem as I believe the wiring and breaker are correctly installed.
Expert:  Kevin replied 7 years ago.
Are there other breakers in the panel beside the two 30's? If so, what are they?
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Customer: replied 7 years ago.
Of course. dryer DP30 amp, all the other unit power mostly on 15 amp breakers. One of those new GFI bedroom style which are required in Canada. Oven DP30 amp, cooktop DP30 amp and 20 amp wiring for the kitchen counter T-slot plugs. Bubble tub I believe is a 20 amp. As I am not in the unit at the moment I can't count them all for you.
Expert:  Kevin replied 7 years ago.
That seems like way too much for a 60 amp box. That may be why you had to move the other breaker down, it may have been on a phase that was overloaded. An easy way to know would be to turn off all the breakers except the one to the oven. If the oven works then, you will know that you are just using too much power from that 60 amp box. You might be able to juggle the breakers around a bit and balance the load on the phases, but I'd still say to use all that, you may have to have a bigger service brought into the unit.

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