I just changed my gas cooktop from an older Bosch model to a new Thermador.

The Bosch worked fine for a quite some time (I bought the house a year ago) and the old Bosch looked to be 15 years old? So it must have worked for quite some time, with no problem.

The new Thermador, when plugged into the same outlet, continuously tries to ignite the burners, without even turning them on. Manual says "house wiring incorrect, call an electrician"

SO -- I investigate and here is where the help is needed.

a) I tested the outlet with a circuit tester - BOTH the 110v and 220v lights, light up.
b) In testing the ground, only the 110v lights up, under both combinations
c) I located the circuit breaker - it's a 30AMP circuit breaker...
d) Looking at the outlet, it is a 20amp outlet, and appears to be wired correctly (ground to ground screw, white wire to light screw, and black wire to dark screw)

When I flip off the 30AMP circuit breaker, I have been unable to find anything else in the house on that circuit.)

Specs for the new gas cooktop are for a 60 Hz, 15 Amp, 120 VAC connection.

HOW do I get what I need out of this....????

Tx

 

Welcome to the forums.

Is that a single pole 30A breaker or a two pole breaker ?
Do you have an actual AC voltmeter ?

 

I assume two-pole? One white wire, and one black wired into a two-switch (attached together) circuit breaker.

Yes I do have an AC voltmeter.

 

Is it a 120 volt receptacle? That is will it take a plug such as used on a lamp?

Do you also have an electric oven on the same breaker?

Use the multimeter to get a true reading. If it is really a 120 volt receptacle measure fom wide slot to narrow slot.

 

I plugged a lamp into the outlet -- it works.

I measured the volts - I get 222v

No, there is not an electric oven on the same circuit. I have one electric oven, and one microwave.

My gut tells me that this is the former circuit for another electric oven that was demo'd and replaced with the microwave... Gut feel only.

I can't find any other appliance or outlet in the house that goes dark when I switch off the circuit breaker

 

A 120v lamp should have exploded.

It sounds like you may have a multiwire branch circuit but the 30A breaker confuses the issue.

Someone may have tried to convert a 240v circuit to a 120v circuit and did it incorrectly. Until it gets figured out..... don't plug the range back in.


Can you measure from the small slot to ground and the large slot to ground ?

 

OK thanks. So here's a thought.

Can I just pull the breaker and kill the circuit? Assuming I can't find anything else on the circuit?

Then, I can add a new outlet that ties into the line that powers the island outlet(s) to supply the cooktop? The cooktop can't take much, and it's only in spurts (when you light the gas...)

Thoughts?

 

Both small to ground and large to ground measure right about 120 vac.

 

This is a 240 volt circuit for an electric cook top. A receptacle should have never been installed here. Another case of a white wire assumed to be neutral. I could be wrong.

To confirm if it is 240:
Check voltage between white wire and black wire, if it is 240, stop everything.

 

He has already confirmed the presence of 240vac.

You can go to the electrical panel and remove the white wire from the breaker and connect it to the neutral bar where the other white wires are connected. Change the breaker from a two pole 30A to a single pole 20A breaker and a blank or put in a second breaker to fill the hole and could be for future use.

 

Please delete my posts, just confuses things. I posted late.

 

And I am confused why the lamp didn't blow.

And just for the record I did NOT say plug a lamp in. I asked: