Swapping out a built in oven next week.

[Ned Flanders]

I will be swapping out a built in oven next week (for my dad) and I had an electrical question. The current oven is on two breakers one 30amp and one 50amp.

Is it normal to have two different amperages going to the same oven?

The two breakers are not paired at the switches and can be switched separately - is this normal?

I have no problem swapping out the old breakers if needed.

My dad was told there are only two wires on the new oven. I would have assumed there would be more wires if it required the same connections as the old oven?

I will know more on Monday when it arrives and I can RTFM. :)

Thanks in advance for any insight you might have.

[Ken]

Is this oven an electric oven?? You hint that it is, but you do not specifically say so.

Are both breakers single pole?? Or is one a double pole?

I would ask your father to check this again if you are dealing with an electric oven. I have never seen an electric oven running on 110 volts, and that is what it would have to be if your father is correct.

[Ned Flanders]

Yes it is.

Both are single pole

That is also what I was thinking, he most likely got it wrong.

[EXT]

Go on the new oven's manufacturer's website and look up the installation manual. It will tell you what you need for your new oven so that you may plan your attack and get the materials ready to reduce the last minute running to the store. In many cases the requirements and wiring connection locations are going to be different than whatever your old oven had, no matter how it was wired.

[hrhofmann]

Something definitely does not compute here, both what your father was told, and the two different non-paired breakers. I hope that both statements turn out to be wrong. I hope you have a good voltmeter that you can use to check things out before you electrocute someone due to bad wiring.

[Ned Flanders]

I came very close to doing that - thats how I figured out there were two separate breakers for the oven. luckily I am very careful around electricity found it was still hot using my tester.

I have had other electrical issues to chase down in his house. I still have to find where the old homeowner broke the connection to the ground in a chain of outlets. I just haven't had the time.

[Ken]

If one leg of the 220v is coming from a 30amp and the other is a 50amp, you have a problem. It is not just the amperage of the breaker, but possibly the gauge of the wire being used. If you have the ability to determine if there are two separate circuits of different gauge coming to the oven and the wire is not correct, you need to correct that. If not, call an electrician. Saving money is one thing, burning your house down is another.

Penny wise and dollar foolish, comes to mind.

[The Daring Dufas]

Are you going to enlist the help of your neighbor Homer Simpson?

TDD

[Ned Flanders]

No - all my tools are left handed!

[Ned Flanders]

The bill of sale does not have the model number but the oven I found seems to have the same options my dad described.

If I found the correct oven it looks like I will need;

A 3-wire or 4-wire single phase 120/240 or 120/208 Volt, 60 Hz AC - and it looks like based on the wattage needed for the two elements it should only need 30amps.

Until I get the plate off of the box under the old oven I will not really know what I am dealing with.

I am assuming I will find two romex cables entering the box from the two breakers. Both runs are on a different phase, but one run is 30amp and the other is 50 amp. The moron who installed the oven probably connected the red wire from the oven to the black on the opposite phase. Although I should not rule out the possibility he used the correct wire and did something strange in the breaker box.

Rest assured if I feel like I am in over my head I will get him to call an electrician.

[aemeijers]

Is there an easy route from oven location to service panel? Are there open holes in the box so a proper ganged breaker could be installed, even if you have to move some nuisance circuits around? I'm no code expert, but I always was under impression that a 240v oven feed had to come in on ONE cable, unless it was individual leads pulled through conduit. If you see it coming in on separate feeds off non-joined breakers, I'd spring for a proper rewire job. Your dad (or you) will be selling that house someday, and an electric oven without a labeled ganged breaker to feed it, will jump out at even a half-ass home inspector.

[Ned Flanders]

By no means would I even entertain the idea of keeping the breakers the way they are. They are an accident waiting to happen. I guess I will have to wait until I can open up the box and/or breaker panel. The breakers are side by side right now so I should not have to move anything around to put in a proper one. Its just the wiring that might be the problem.

[hrhofmann]

It sounds like you have a fairly good knowledge of what you are doing, please post whatever you find, it helps us to help the next person.

[krw]

Ohh, Scary! ...but Halloween was last weekend.

Cartainly not.

No. They must be paired. A nail through the handle to link them together was enough at one time but I don't think so anymore. The good news is that breakers are cheap and easy to replace, if that's all that's wrong here.

Do it! When you do, check to make sure the wires connected to these breakers are in the same cable. The wire on one breaker should be black and the other red. Hopefully someone just replaced the breakers with what he had as a quick repair (penny in the fusebox sort of thing) and forgot about it.

Could be. The third, the safety ground, would come from the chassis. This presumes that there are no 120V devices in the oven (e.g. a timer).

[Gary H]

Didn't the OP say he had a wall oven, not a range? Those can be on a 30A circuit (separate from the stovetop). I have 2 240V 30A circuits, one for the stovetop and another for the wall oven.

[Colbyt]

Ned from reading your replies I am fairly sure you are smart enough to figure this one out when you are looking at the actual box.

Double pole breakers do not always have two handles but the always occupy two spaces. SquareD for one uses an internal trip on the second leg. So both of these may be 220 breakers.

The other thing is I don't ever recall seeing a single pole breaker greater than 30 amps. As a couple of others have mentioned a single wall oven only uses a 30 amp breaker. The cook top may be on the 50 and the oven on the 30 though I think the installer should have downsized the breaker. I think cooktops only use a 30.

Do let us know what you find.

[Ned Flanders]

Well I had a chance to open things up and here is what I found;

Both of the single pole breakers are 30 amp (note to self - don't send a

78 year old to read the amperage on a breaker).

The cable is the correct copper 4 wire needed for a 240V appliance and it appears to be the same gauge or possibly thicker than a the gauge of wire attached to a 50 amp double pole breaker added by an electrician about 10 years ago to feed the sub panel that was added for the basement suite.

Here is the fun part - somewhere under the tile ceiling in the basement there has to be box that feeds the cook-top off the same cable. I can't believe both the cook top and oven are on the same 30 amp breakers.

I will have to verify the gauge of the wire but my gut tells me it can handle the double pole 50 amp breaker that will be needed to power the new oven and old cook-top.