Electric oven tripping circuit breaker after turned on for 3-5 minutes

[beetle1303]

My electric oven was working fine all the while from purchased 2 years ago. I have been using it weekly for about a year, but stopped using for a year now since then.
When I turn it on again yesterday, the tripped the circuit breaker and whole house no power supply. I reset the circuit breaker, and retried. Same thing happened.

This is what happened:
- Turned on the oven power supply, set temperature to 200c, everything worked for a few minutes, then the power tripped. Oven was warmed/hot.
- Reset circuit breaker, retried, same thing happened.

I googled and found out that this is very common for electric oven - when left with not using for a long time, moisture sipped into the heating element. And when power on, it caused earth leakage and tripped the circuit breaker. This is especially common in humid tropical countries.

Among the recommended fixes - set the temperature to min. and let it run for few minutes, then up the temperature and repeat the process till to reaches max temperature without tripping. I tried this but it tripped at min temperature within minutes.

Another one is the disconnect the earth wire from the wall plug. Run it for an hour or so to dry out the elements. I fell this is too dangerous so did not try this.

Last recommendation is to remove the elements. Put it into another heated oven/stove, or use hair drier to heat it up to dry out the moisture.

I have now taken out the elements preparing to do this.

My questions:
1) Using DMM in continuity mode - the terminals measure around 48-52 Ohms. Terminal to metal loop measured 0L. But in resistance mode, it measure ~3M Ohms.
Is this normal ?

2) How to check to confirm the element is causing the power trip?

3) To simulate the heated element leakage, can I use a laptop adapter as power source and wire a light bulb to see if it lights up?

Thank you.

[diif]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

That's a failed element, the insulation has broken down a little inside which shows itself when it gets hot.

[beetle1303]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

That's a failed element, the insulation has broken down a little inside which shows itself when it gets hot.

You think it's due to moisture after prolonged unused? Is any of those "heating it up to dry out the moisture" methods would work?

[diif]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

Not moisture, they are sealed, just replace it.

[sam_sam_sam]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

Yes just replace the heating element

The way to check them is with the power turn off take the wires off the element and check the resistance from the terminal to outer shell of element you should NOT have any resistance at all if you do you have a BAD element

[petehall347]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

real way to check is with a pats tester . i guess a megger would do a good job too . there might not be enough current from a digital multimeter to see the leak . its sounds obviously a bad one anyway . one pretty safe way to test would be remove the wires going to it and insulate them then turn it on .

[sam_sam_sam]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

Another way you could do it but you must be very careful doing this is the disclaimer

Take a 100 watt light bulb and one wire to the element the other end of wire to outer case of the element and going to do this as follows

Line side —— one wire to the light bulb — — the other end of light bulb wire to the element terminal — — another wire goes to the outer case of the element —— and then to the neutral side of the plug

Under no circumstances should you touch any part of the element with it plugged into the outlet you could get electrical shock or worse

PLEASE be careful doing this test I do not want to see any one get hurt doing this test

When doing this test you should not see the light bulb light at all if it does the element is bad

I have done this test on devices like heater elements that I think could be internally shorted I have even done this air conditioning compressor if I do not have a insulation tester with me and all I have is a light bulb tester

I hope this helps you

[beetle1303]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

real way to check is with a pats tester . i guess a megger would do a good job too . there might not be enough current from a digital multimeter to see the leak . its sounds obviously a bad one anyway . one pretty safe way to test would be remove the wires going to it and insulate them then turn it on .

With both elements now removed from the oven and all connectors insulated, turning on power and switching to various modes, nothing happens and no power trip.

[beetle1303]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

Another way you could do it but you must be very careful doing this is the disclaimer

Take a 100 watt light bulb and one wire to the element the other end of wire to outer case of the element and going to do this as follows

Line side —— one wire to the light bulb — — the other end of light bulb wire to the element terminal — — another wire goes to the outer case of the element —— and then to the neutral side of the plug

Under no circumstances should you touch any part of the element with it plugged into the outlet you could get electrical shock or worse

PLEASE be careful doing this test I do not want to see any one get hurt doing this test

When doing this test you should not see the light bulb light at all if it does the element is bad

I have done this test on devices like heater elements that I think could be internally shorted I have even done this air conditioning compressor if I do not have a insulation tester with me and all I have is a light bulb tester

I hope this helps you

I have done the light bulb test according to your wiring scheme - no light.

I am guessing it would probably only light up when the element is heated up...

Is it safe redo this test by heat up the element by adding another wire connecting the other terminal to neutral?

[beetle1303]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

OK. I didn't re-do the bulb test, but simply heating the element to measure the resistance.
To be safe, I put the element on the clay pot on a ceramic tile floor, wore a rubber gloves and rubber shoes. I turned on the power for few seconds at first, then left on for ~30 seconds then switched it off. The element didn't grow red but can smell the heat.
I then measure resistance between terminal and the outer shell - it fluctuated a lot for 20-30 seconds, stabilized ~60K Ohms.

Not sure at this level it will already trip the power, but most likely as the temperature goes up further, it eventually will.

Based on everyone's' input, it is already clear that the element is bad. For my own academic, I am just curious to see the outcomes.

I am guessing, based on what I have researched, that the old days oven heating element's insulating material was some kind of powdery form. When not used for a long time, it could absorbed sufficient amount of moisture around the terminals and becomes conductive. Whereas modern oven element like the ones I have, is solid plastic sealed tightly type and therefore moisture issue does not apply. And therefore many of the recommendations to fix this power trip issue also not valid..

Question remains - when used regularly this heating element seems to last for years. What is causing the heating element to go bad when left unused for a long time?

[petehall347]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

try connecting one element at a time .

[diif]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

Question remains - when used regularly this heating element seems to last for years. What is causing the heating element to go bad when left unused for a long time?

Nothing, they also fail if regularly used.

[beetle1303]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

try connecting one element at a time .

Yes, in fact I only this on the lower single loop element. I reckon would be the same results on the upper double loop element also.

Wouldn't it?

[beetle1303]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

Nothing, they also fail if regularly used.

My previous oven element broken on regular used for 5-6 years, never had a power tripped before.

This one is new and never had a power tripped before either when use regularly. It only tripped now after laying idle for a year or so...

There must be something about those element insulator when left unused for long time. Maybe like come rubber shoes or PVC bags, they peeled, cracked, or disintegrated when not in used for long time?

[diif]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

My previous oven element broken on regular used for 5-6 years, never had a power tripped before.

This one is new and never had a power tripped before either when use regularly. It only tripped now after laying idle for a year or so...

There must be something about those element insulator when left unused for long time. Maybe like come rubber shoes or PVC bags, they peeled, cracked, or disintegrated when not in used for long time?

Just a coincidence. My friend fits 2 or 3 a week and those ovens are regularly used. The one that failed ion my oven is also used regularly.

[beetle1303]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

Just a coincidence. My friend fits 2 or 3 a week and those ovens are regularly used. The one that failed ion my oven is also used regularly.

Do they all, and yours, failed due to shorted to earth that tripped the power supply like mine?

[sam_sam_sam]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

OK.
To be safe, I put the element on the clay pot on a ceramic tile floor, wore a rubber gloves and rubber shoes. I turned on the power for few seconds at first, then left on for ~30 seconds then switched it off. The element didn't grow red but can smell the heat.
I then measure resistance between terminal and the outer shell - it fluctuated a lot for 20-30 seconds, stabilized ~60K Ohms.

Not sure at this level it will already trip the power, but most likely as the temperature goes up further, it eventually will.

Based on everyone's' input, it is already clear that the element is bad. For my own academic, I am just curious to see the outcomes.

I am guessing, based on what I have researched, that the old days oven heating element's insulating material was some kind of powdery form. When not used for a long time, it could absorbed sufficient amount of moisture around the terminals and becomes conductive.

If this is the results that you got on this element then this one is bad

If you look at the element ( every inch of it ) with a magnifying glass you might see a place where there is a hair line crack or pitting in the outer shell this caused by hot liquid spilling on the element

This is also an indication of the element bad or going bad

There is also a situation where the bracket or brackets that hold the element up can cause issues as well

The medium is some type of ceramic material not sure what type

[beetle1303]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

If this is the results that you got on this element then this one is bad

If you look at the element ( every inch of it ) with a magnifying glass you might see a place where there is a hair line crack or pitting in the outer shell this caused by hot liquid spilling on the element

This is also an indication of the element bad or going bad

There is also a situation where the bracket or brackets that hold the element up can cause issues as well

The medium is some type of ceramic material not sure what type

I am actually very convinced that the element is bad. All these tests are really just to satisfied my curiosity.

But what is puzzling me is that there seems to be many cases where electric oven tripped circuit breaker when re-use after a long time of unused. So what happened to the heating element when it is left unused for a long time? It would appear that the insulation turned bad for some reasons, and what would those reasons be??

[sam_sam_sam]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

My guess is that when you use the element more often there is no problem at point of time but there are issues that are not fatal

But when you let it sit for a moisture get into the ceramic material and causes an internal short or and rust when heating up the moisture reaction with the electricity causing current to flow to ground

This is just a guess at this point

[clearchris]

Re: Electric oven tripping circuit breaker after turned on for 3-5 minutes

There's a few things that will fry a heating element aside from a manufacturer's defect. You have things that will insulate the heating element and cause it to go high at one spot and burn it, like food residue or lime scale (in water heaters). Physical damage is pretty hard, these elements are tough. The other thing is a bad thermostat. If the thermostat doesn't properly turn off, the element will get too hot and burn. So when you replace the element, you should get a meter with a thermal probe and watch it. Periodically check it a few times after that too, if it's a mechanical thermostat, they don't always just go bad, instead, they get "sticky" and sometimes overheat the element.

If it did burn after a long time of being idle, I'd definitely take a look at the thermostat. An easy way, though not always conclusive, is to turn the knob and feel the click when the thermostat kicks in. You might not always feel the click turning on from cold, but after it's somewhat warm, you should be able to turn it both ways and feel it click on and off. If you don't feel the click, it might be bad. Don't confuse the "off" click with the thermostat kicking in, some have a dentent that clicks when you turn it all the way off.

Also make sure to clean the terminals, if you have a bad connection, this can also send the current high enough to pop a breaker. Sometimes the female spade connectors need a squeeze to tighten them up again.

Edit: if you do replace one element to test, make sure you are aware of where the thermostat bulb is. They are often placed near one heating element, and if that's not the element you put in, the thermostat isn't going to turn off, and you could burn a good heating element.