Why does my range trip the circuit breaker when the oven and all burners are used?
November 14, 2011 7:40 PM   Subscribe

Why does my electric range trip the circuit breaker when the oven and all burners are used? This behavior is new.

I have an early 80s GE electric oven/cooktop range (approximate parts diagram) on a pair of dedicated 50 amp circuits of the same vintage. The range is marked 10.6 KW @ 120V and 8.2 KW @ 120V. Pretty much everything in the house is the cheapest imaginable, but I haven't found any safety issues.

I used to be able to use all four burners and the oven at the same time. Recently if I turn on everything, after a minute or so the breaker trips. I have also had this happen with only a couple burners and the oven at the same time. It does *not* happen with just the oven, even if I leave the oven at 500F for an extended period. Resetting the breaker is always sufficient to turn things back on.

Thinking a short caused by thermal expansion was the most likely cause, I checked all the burners (including the oven element) where they connected to the wiring, and everything seemed in excellent shape. Pulling out the panel with the knobs, there was a lot of wiring but all the terminals looked fine and I didn't see evidence of scorching like you would expect with a short. This model comes with a mechanical timer that could be an issue, but I wasn't about to take it apart.

Since Thanksgiving is an 11 course cornucopia, every burner (and the grill) are strictly scheduled. Ideally, I would take my handy multimeter and diagnose this problem. If y'all advise, I'll call an electrician instead. Replacing a built-in range at T-day minus nine days is not on my list of fun, but we can do it.
posted by wnissen to Home & Garden (17 answers total) 1 user marked this as a favorite
Is there anything else on the same circuit as the stove? A new lamp? The dishwasher? etc?
posted by chrisamiller at 7:55 PM on November 14, 2011

Response by poster: Nothing else is on those circuits (not even the vent). I checked on our electrical meter, and the house as a whole with all burners and the oven on is drawing about 10.5KW/121V (again measured at the meter) = 87 amps, so the 100 amp total capacity should be plenty, at least by my estimation.
posted by wnissen at 8:01 PM on November 14, 2011

How old is the house and wiring? Our last house was from the late 60's and a few years back I had to replace one of the breakers. The electrician at the time said "All of this stuff wears out at some point, so why not now?"

I am not an electrician but besides this time I've seen weak breakers start to trip more frequently over time, with the same load they used to have no problem with. If you can, call an electrician, or better yet, go to an electrical supply store and find the oldest person there behind the counter and ask him what he/she thinks. This has always worked a treat for me. Good luck.
posted by chosemerveilleux at 8:10 PM on November 14, 2011

Best answer: IANAEBIAAEE(-i s)

I am not an electrician but I am an electrical engineer (-ing student).

disclaimer: electricity is dangerous and deadly. Advice from a website is worse then advice from an electrician.

Are you sure it said 120V on the back? if your in the US the electric range should be hooked up to 240V through split phase (two out of phase 120V lines that equal 240V) and by code nothing else can be on that breaker.

You would read 120V at all normal outlets, and from hot to neutral you should read 120V, but from hot to hot either in the breaker box, or at the stove you should get 240V if your wired for split phase. You have two 50A breakers, one for each phase.
posted by token-ring at 8:11 PM on November 14, 2011

Sorry hit post too soon,

It could be something small like breakers getting weak. Could be an element in the stove getting old and drawing more then it used to. Could be wires heating up in the wall. Could be any number of things, but if you need all 4 burners on in 9 days you might want to contact and electrician and get his opinion.
posted by token-ring at 8:16 PM on November 14, 2011

It's telling you to have the stove and circuit tested. Maybe the stove has a short and is pulling too much current. Maybe the wiring has developed a problem. A tripped breaker is a better message than a fire.

My electric stove burner went bad, and began arc-ing. Very exciting 1st thing in the morning. Lesson: 6 year olds love it when firefighters come to visit. Resolution: replace the burner.
posted by theora55 at 8:19 PM on November 14, 2011

I am an EE but not your EE...

Circuit breakers do wear out, especially if they've tripped quite a few times, as yours seems to have. Also they typically have internal arc suppression devices that can cause trouble after a few trips.

Seconding Token-Ring, stop opening things that might kill you and get professionals involved.
posted by Confess, Fletch at 8:33 PM on November 14, 2011

Response by poster: chosemerveilleux, the house is early 1980s.

token-ring, thanks for your contribution. Phased power certainly explains why the wattages are specified as 10.6 @ 120/240V, which I got wrong. I am aware that by attempting to trip the breaker I am essentially inviting electrical fire if the malfunction is other than in the breaker, but otherwise I am taking reasonable precautions. I turned off the power at the breaker when investigating wiring in the stove, and I will turn off the main when replacing the breakers. Am I really putting myself at risk if I take those precautions?

A new set of burners would be $270 from GE, while a new breaker is $10, so it seems like the first course of action would be to replace that. It has indeed tripped quite a few times. Can I just take the old breaker to my local big box store and match it to a new one?
posted by wnissen at 8:40 PM on November 14, 2011

I just had to replace a breaker that had begun to trip under ever smaller loads.
posted by bz at 8:51 PM on November 14, 2011

I am in the construction field, but not YOUR construction field, etc.

Electricity is some serious stuff. I would consult a professional. He or she should be able to diagnose the issues and recommend a solution, which you may be able to implement yourself. I am not able to diagnose these issues from what your describe.

Stay safe!
posted by the man of twists and turns at 8:52 PM on November 14, 2011

Also, if you want to take the House MD method of problem solving, replacing the breaker would be my first bet. You should be able to take it to a local hardware or big-box store and get it matched.
posted by the man of twists and turns at 8:53 PM on November 14, 2011

If your not 100% comfortable with what your doing I would recommend an electrician, but you sound intent on saving money; a warning: If you do attempt to replace breakers yourself read up on the steps and precautions carefully. This is a good start. Make sure to turn off all breakers, then turn off the main, triple check every voltage at every point with your meter before continuing, and be very wary of the connections to your main breaker from outside; they will be live. Outside the protection of your main breaker is a direct connection to the local grid, probably with no protection between you and crap-ton of power.

If your still intent on diy, and at any time you see something that confuses you or you feel uncomfortable, stop and call an electrician.
posted by token-ring at 8:56 PM on November 14, 2011

At full load, 10.6 KW at 240v, you'd be drawing 44 amps... pretty close to the 50 amp breaker rating. Either one might trip; they're carrying the same current, if there's nothing else on the stove circuit. (And there shouldn't be, as token-ring sez!) The 87 amps you measured at the meter would be whole-house current, must be some other stuff on. What did you use? an Amprobe or equal?
I'd second the breakers getting weak (or at least one of 'em- does one trip more than the other?) Once a breaker trips the first time, it becomes a bit less repeatable. bz's experience above is common, in my experience. Replace 'em, should take care of the problem. And yes, follow token-ring's advice!
(EE and old ham here.)
posted by drhydro at 10:02 PM on November 14, 2011

Get an electrician to come out for half an hour as a non emergency and tell you what needs to be done. My wife is a theoretical physicist, so her understanding of electricity is very deep. She absolutely refuses to have anything to do with practical household electricity, presicely because it's dangerous and best left to the professionals (as noted by previous posters). A good electrician should let you know of a DIY solution if one exists though.
posted by singingfish at 11:40 PM on November 14, 2011

I'd spend the ten bucks and replace the breaker first. Use common sense and you should be fine.
posted by jmsta at 3:37 AM on November 15, 2011

Best answer: I really doubt this is a problem with your burners; certainly not all of them. My feeling is this is indeed a weak breaker. I'd change it out on spec if I didn't have access to a clamp on amp meter. What kind of panel do you have? I ask because some panels can be tricky to deal with; if you can ID the panel I may be able to give some directed helpful advice.

Some thoughts:
  1. Healthy breakers don't trip when you get close to their rated current. In fact the opposite is true; you can often overload a breaker by 10% indefinitely. Especially if ambient temperatures are low.
  2. Generally speaking your four burners will draw more current than than your oven.
  3. Unlike say motors, elements never fail by drawing more current in the long term. IE: once they start drawing more than rated current they pretty well immediately self destruct
  4. You can get increased current draw at switches from wear but that is usually accompanied by darkening, melting and charring of wire going to those devices and you've said you can't see any of those indicators
  5. It is rare for wiring to spontaneously degrade in the wall and the circuit serving your stove usually makes a direct run between the panel and the stove outlet.
  6. Stoves rarely draw their full rated amperage. The oven cycles off and on as do the infinite heat switches controlling your burners
  7. One place you might have a problem is where the wire connects to the outlet; especially if you have aluminum wire so have a close look at your plug.
When you go to turn off your main to replace the breaker first turn off all the individual circuit breakers one at a time. This will minimize the risk of a dangerous arc flash over. After installation turn on the main breaker first and then all the circuit breakers one at a time. This will again reduce the possibility of an arc flash over and it minimize in rush currents to your system. Make sure you use only one hand to operate the breakers. Stand so that you are not directly in front of the panel (IE if you are using your left hand stand to the right of the panel and vice versa). And finally look away from the breakers when operating them.

PS: Technically speaking breakers are rated to trip because of overload exactly once because the unpredictable wear on the contacts will reduce their rating (or in the case of say a Zinsco panel will sometimes fuse the contacts together)
posted by Mitheral at 6:28 PM on November 15, 2011 [1 favorite]

Response by poster: I just cranked every element on the stove to high and left it there for ten minutes! It was the breaker, thanks all. I was indeed able to match the specs and shape exactly, and got a new one for ten bucks. The longest part of the whole process was driving to buy the breaker. I was indeed careful to use one hand and look away during the moments when I could have generated arc currents. (Actually, I didn't take those precautions the one time I replaced a dead breaker before, which means you taught me something, thank you all.)

Thanksgiving is ON!
posted by wnissen at 4:27 PM on November 19, 2011

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