Help with oven and breaker!

Question

a month or so ago, I posted on here that my oven kept tripping my breaker. It’s an old oven (20+ years at least). If it would get to a certain temp, it would cut off. Oven light, everything. I’d go to the breaker and it would be tripped. I got a new oven today, I’ve heated it at 375 just to test it. While, the breaker did not trip, it felt pretty hot. I would imagine if I left it on, it would trip. With thanksgiving coming up, I’m gonna need it to cook in lol.

This is the spot where it gets hot. Exactly where the arrow is)

I took the old stove out and this is how it was hooked up

The new stove hooked up fine. I’m just wondering if I need to just replace that box out completely and the breaker. Any help or recommendations would be greatly appreciated.

Thanks

Answer 1

There are, broadly speaking, 4 different possible problems:

• The oven

The previous oven may have had an electrical problem, but it is very unlikely that a new oven would have a problem. If the breaker tripped immediately when the oven was plugged in or when starting a particular cycle (e.g., bake vs. broil) then that would be a likely oven defect. The breaker tripping after the oven has been on for a while, particularly with a new oven, is likely to be a problem someplace else.

• The receptacle/box

There is a big looming safety issue with the receptacle. It is an older ground-on-neutral NEMA 10. It should be a NEMA 14, with the ground-neutral bond in the oven removed. But that is not by itself going to cause a breaker trip.

Unfortunately, it appears that you have a 3-wire cable without ground. Assuming that's the case, switching to NEMA 14 will require getting a ground from elsewhere, which may be easy or may be hard. You can attach to another ground, but the ground on a standard 15A or 20A circuit is not large enough for a 30A or 50A circuit. That's separate discussion should you be ready to pursue it.

However, there can be problems in a junction box if there are loose or corroded wires. The connections can heat up, arc, start a fire, melt the box, etc. All bad things. So making sure that the box, receptacle and wires are assembled properly is important. But I doubt it is the source of the breaker trip.

• The wires

The wires need to be able to properly provide the power needed by the oven. The breaker needs to protect the wires. There are some variants depending on wire type and some special cases, but generally speaking the standard US copper wire in cables (as opposed to separate wires in conduit) and breaker sizes are:

• 15A = 14 AWG
• 20A = 12 AWG
• 30A = 10 AWG
• 40A = 8 AWG
• 50A = 6 AWG

In a quick search, it looks like 8 AWG can actually handle 45A. There may be a basis for allowing a 50A breaker on 8 AWG wire, since 45A breakers aren't a standard item, but the actual load of the oven is a key factor. Oven power requirements vary quite a bit depending on size and features.

The issue is that if the breaker is larger than appropriate for the wires, the wires can overheat without the breaker tripping. That is actually the opposite of your problem here, so I doubt it is the wires. However, you should check the size of the wires and the requirements of the oven. If the wires are 10 AWG or smaller then you need to switch to a smaller breaker. Check the oven specifications for the required breaker size. If it doesn't list the breaker size then look at the power requirements, multiply by 1.25 because of continuous usage, divide by 240 (assuming you have 240V power) and that is the minimum number of Amps that your wire needs to provide, and you breakers need to allow, to function properly.

• The breaker

The final piece, which I suspect is the culprit here, is the breaker. You feel heat in the breaker. If everything is running properly, the breakers should not be noticeably warm. That is an indication of either a problem with the breaker itself or, as with junction box problems, the connection to the breaker. The connection to the breaker includes both the wires going into the breaker and also where the breaker connects to the panel.

Turn off the main breaker. Remove the wires from the breaker. Remove the breaker. Look for signs of arcing or other problems. If everything looks OK then more likely the breaker. If there are signs of problems, it may be easily fixable or that breaker space may be unusable. If the breaker is also the wrong size (see above) then replace it with a new breaker. If you're not sure about the problem, it may be best to replace it with a new breaker - typically $10 - $20.

Answer 2

Holes in panel

Aside from what manassehkatz discusses, the breaker panel has gaping issues that you might as well address while you are buying the other breaker.

Those 1/2” wide openings, waiting for curious fingers, are a code violation and safety hazard. They need to be plugged either by installing thin blank cover plates into the lid (GE should stock these) or by replacing the thin breakers with full width breakers.

Breaker selection

I have heard that modern full-size GE THQL breakers will not fit in very old GE panels. I suspect that is why, in previous upgrades or changes, previous electricians substituted those GE "thin" breakers. Don't do that yourself, unless you are willing to fit the aforementioned blank cover plates.

There is one alternative, a type that will be special-order at a home store but stocking at an electrical supply house which is an Eaton dealer. That is the Eaton CL line of breakers.

The hopeful GE model is THQL250 for the range and THQL230 for the 30A breakers. Expect under $15.

The definite Eaton CL model is CL250 for 50A, and CL230 for 30A. Expect under $30.

Split-bus panel

It is what is called a "split-bus" panel. It does not have a main breaker. The several breakers in the "main breaker" area are the main breakers. This is also called a "Rule of Six" panel because there must be no more than six handle throws to shut all the power off.

Normally, a split-bus panel is viewed with alarm. That is not because the several breakers (50, 30, 30? And 60? amps) add up to more than the 100A service rating. That issue is addressed by a load calculation when the panel is initially installed, which proves the panel is unlikely to be overloaded.

Indeed, your loads appear modest.

The issue is upgrades. When people add air conditioner, hot tub, shop, EV or whatever, they should but don't re-compute the Load Calculation for the added loads. Often the installer is inexperienced and does not realize it is a split-bus panel. They overload the panel without even realizing! And nothing stops this.

For this reason, I recommend people with old split-bus panels bite the bullet and add a main breaker prior to the panel. Sometimes this isn't hard at all and can be done with a call to the power company to turn off power at the smart meter. Other times your electrician pulls the meter and a clerk must come out to replace the seal... or the meter pan must be replaced, requiring visits from the power company to remove and replace the service drop.

Once an outside main breaker is present, the safety issues with split-bus panels are nullified and you can freely use any space without restriction. This means you have more breaker spaces available, e.g. "creating" eight of the GE half-spaces.