Hey all, first off I don't know much about electrical stuff.

When I turn my oven on, and just keep it at 140 degrees, everything is fine. If I turn it up to +/- 180 degrees, it's fine for a while, but when it reaches the actual heat, my power trips.

Now I know that I=V/R, so I guess when it heats up and the resistance increases, the current has to increase to still maintain the power put out by P=V*I? Cause the voltage stays constant afaik?

Also I was wondering, lets say it consumes X power at 140 degrees, and Y power at 180 degrees. If I turn the knob to 180 degrees from 140 degrees, it immediately consumes Y power right? That's what sounds logic to me. And that just makes me think that it doesn't trip because it immediately consumes too much power, but rather cause the current has to increase when the resistance increases, and thus the Circuit breaker trips?

Sorry if I said stupid things or sound clueless, thanks. :)

I would be sure the Breaker is the right size for the wire, and Breaker/wire size is correct for oven.
I would check the wires are tight on breaker, and breaker tight on clean buss(not burnt).
Clamping an Amprobe around supply wires will show actual amps.

Your oven has two elements, it's possible that when the second element comes on it trips the breaker... it may be shorting. If you turn on all of the stove top elements does the breaker trip, or perhaps all the top elements and the oven at 140? Is this a new installation, or existing that you recently started having these issues with?

Missouri could be on to something. I would also check the breaker itself. I have had these get "weak" over time and open up prematurely.

All good sugestions, I'll add one:

A typical oven has two elements, a regular bake element on the bottom, and a broiler on the top. By just setting a temprature on the bake thermostat, the broiler element should not operate.

Since I'm going to assume the oven has worked in the past, and has all ove a sudden started acting up, I'm going to figure the breaker and wire size are correct. However if this is a new oven, then definitely, breaker and wire size would be something to check into. Most ovens require at least a 40 amp breaker.

When the oven trips the breaker, is the breaker hot?

Pull the oven out, is the plug hot?

A loose connection where the plug meets the outlet can increase the amperage as it heats up.

Also check where the cord attaches to the oven itself. Often times the homeowner installs the cord on the oven, and doesn't tighten the lugs down tight enough and it works loose. It may be jerry rigged too. I saw that on a dryer once.

It almost sounds like there is a poor connection somewhere. Follow the heat. What ever is getting hot that normally is not will most likely be the problem.

You could have a "thermal short."

This type of short circuit occurs when the element reaches a certain temperature, then disappears when it cools off.

[QUOTE=ensiferum;1873020]Hey all, first off I don't know much about electrical stuff.


Now I know that I=V/R, so I guess when it heats up and the resistance increases, the current has to increase to still maintain the power put out by P=V*I? Cause the voltage stays constant afaik?

Also I was wondering, lets say it consumes X power at 140 degrees, and Y power at 180 degrees. If I turn the knob to 180 degrees from 140 degrees, it immediately consumes Y power right? That's what sounds logic to me. And that just makes me think that it doesn't trip because it immediately consumes too much power, but rather cause the current has to increase when the resistance increases, and thus the Circuit breaker trips?

Unlike an inductive circuit (motor or transformer) power is not conserved in a resistive circuit.* A lower voltage will result in less current, therefore less power.
Nor does the resistance of the element doesn't change appreciably when it is hot.

Secondly, a home oven has only proportional control. When the thermostatic switch is closed, you apply full power to the element. When the stat opens, power is turned off. (There is no integral or derivative control)

Most likely, your problem is a "thermal short." This is an intermittant short circuit that shows up only when the element is hot, and clears (goes away) when the element cools off.

* Look at the nameplate on a dual voltage motor, then apply the Powers Law equation to both the high and low voltage numbers. For example, a 120/240 volt motor that draws 6 amps at 120 volts will draw only 3 amps at 240 volts. Substituting the Voltage and current values for both connections will yield 720 watts; power is conserved.
But a heating element that draws 3 amps at 240 volts will draw only 1.5 amps at 120 volts, using 720 watts at the higher voltage, and 180 watts at the lower voltage. Power is not conserved.