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120V 240V breaker interaction and new range

Posted by noisebeam (My Page) on
Wed, Dec 8, 10 at 14:28

I just had a new range plugged in (no wiring changes made to 1978 house) The new one was had pigtail wired for three wire 240V to match outlet. (ground connected to neutral inside range)

Soon after I found that the 120V circuit in kitchen would flicker and eventually trip it's 120V breaker. This was not at all load dependent, happens with everything off, doesn't change with everything on.

When the 120V breaker trips the power to the range goes off too, but the 240V breaker for the range is not tripped. If I reset the 120V breaker the range works again. (If I turn off the 240V range breaker the range goes off but nothing else)

The 240V breaker and 120V breaker are not physically near each other in the main electrical panel.

Is this normal that there is a relation between the 120V and 240V like this? Is that a sign of an incorrect wiring job or a failing (neutral?) connection somewhere in the house?

Seems strange this happened just when a new range is plugged in.

Follow-Up Postings:

RE: 120V 240V breaker interaction and new range

You need someone professional to take a look at this. I get the odd feeling that there's a connection between the range neutral an the other kitchen circuit.

RE: 120V 240V breaker interaction and new range

There is something very wrong here. The range should have no effect on 120 volt circuit.
Does the range go off if you turn off the 240 volt range breaker? Sounds like the range is somehow connected to the 120 volt breaker instead of the range breaker.

RE: 120V 240V breaker interaction and new range

It turns out that the 120V breaker had nothing electrical to do with it. I have determined I have a bad 240V mains breaker or bad bus connection so I am intermittently getting half dropping out. This means some of my 120V circuits are intermittently going out.

The reason it 'fixed' when I flipped the 120V kitchen breaker off/on was because that was enough to jiggle the breaker box and temporarily fix the bad connection.

Anyway I am sure it is either the mains breaker or the connection of the breaker to the bus. I am having an electrician come out today to take a look.

He told me on the phone that the aluminum buses on this type of breaker box are prone to corrode, etc. over many years. He said the bus could be cleaned/polished, but more than likely it would fail again soon as once there is surface heating, etc it can't be totally polished away. He recommended a new 200A breaker box be put in for ~$1500 as the busses/back plane are not an available replacement part. Anyway he is taking a look for a quote and said hopefully it is just the mains breaker which is $150 to replace, but that doesn't sound likely.

RE: 120V 240V breaker interaction and new range

Sounds very resonable. The prices sounds about correct also.

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