Lights dimming when oven turns on

Old 12-23-04, 02:40 PM
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Lights dimming when oven turns on

I recently purchased a small apartment complex with a few friends that I've been in business with for a little while.

Recently in one of the apartments one of the baseboard heaters went out. We purchased a new baseboard heater (240V) and realized the old one was on a 120V line. The old heater was a 240V as well. So we obviously couldn't connect the new heater up and are trying to plan what to do next.

What we noticed when troubleshooting the heater before we took it off was that when the oven is turned on, the family room light dims. When it's turned off, it gets bright again. Doesn't that mean the oven and ceiling light are on the same circuit?

There are also two different circuit breakers that will turn off the ceiling light. One of them is the same one as the oven.

I also measured the voltage of both the 120V lines coming into the box. One said 115 and the other was a little over 90V.

I am unsure of what to do at this point. I'm thinking I need to run a 240V line to the bedroom where the baseboard heater is but wanted to see if anyone could advise me as to something else I need to be fixing before adding that.

Why would one of the 120V lines only read 90V?
Why would two circuit breakers both be capable of turning off the same ceiling light?
Should a ceiling light be on the same circuit as an oven?
What does it mean when the lights dim when the oven is turned on?

Any next step suggestions would be greatly appreciated. We plan on hiring an electrician to come do the job but we'd like to accurately assess the problem before hand if possible for our own benefit/education and so we'll know how much to expect this to cost.
Old 12-23-04, 03:26 PM
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You need to hire an electrician NOW. What you are describing is highly unusual and could be very dangerous.

As for cost and what is going on. I cannot comment on cost. It sounds like someone who didn't know what they were doing made numerous changes to the electrical in this system. There could be any number of incorrect hookups. It may take an electrician quite a bit of time to sort it all out, especially if he has to do it multiple times.

I am curious as to how there are "two different circuit breakers that will turn off the ceiling light". I can certainly understand how more than one circuit breaker can provide power for a light (if improperly wired), but I cannot understand how it takes two circuit breakers to turn it off. Perhaps you didn't really mean what you types?

You didn't ask for this advice, but I will give it to you anyway. You should have hired an electrician to inspect the property beforehand. That way the previous owner would have been paying for these repairs, or at least you could have worked it into the price you paid.
Old 12-24-04, 07:16 AM
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There are two different circuit breakers that will shut off power to the same light.

If I turn off circuit breaker #1, the light shuts off. If it turn circuit breaker #1 back on and then turn off circuit breaker #2, the same light shuts off only circuit breaker #2 also controls the oven.
Old 12-24-04, 07:22 AM
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One of your hot feeds to the panel is bad. The oven circuit breaker is back feeding the bad leg though the oven.
Old 12-24-04, 07:37 AM
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I'll bet you'd have a hard time cooking a turkey in that oven too. It probably isn't getting very hot.
Old 12-24-04, 01:17 PM
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Turn off the two breakers NOW. get an electrician !!!!!

You may have an open White neutral on a 240 volt circuit.Can be a Big fire hazard.
The two lights appear to be in series with a 240 volt line with an open neutral.

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