220 volt oven

[mrchips]

hi, i was at a friends for xmas dinner, he said he was having problems with the stove. it wouldnt heat up. and when you turned the oven dial up from 100 to 500 the kitchen lighting would get brighter ?? the kitchen is on the left side of the house.all power on the sid eof the house is acting wierd. power on the right side seems to be fine. i think that there is only 110 v coming into the panel, and the other

110v leg is dead. does this sound right? we did not have a meter to check. the main breaker seems to be fine the panel is fairly new not more than 10 years old. it is in an industrial building, so we cannot acess the mechanical room yet,but i think there will be a fused discconect switch in there. am i on the right track??

[Pete C.]

A bad neutral connection is usually the suspect with symptoms like that. Could be a bad hot, but less likely. Certainly something is amiss and most everything should be turned off until the problem is isolated and fixed.

Pete C.

[Nate Nagel]

I agree, sounds like a bad neutral and should be addressed soon. Might even be a problem with the service, not the house wiring - someone should check it out though.

good luck,

nate

[Terry]

Sounds like a bad neutral to me, too. You can burn up stuff with this condition.

The power company will check their end for free. Call them now.

You should check the connections in the panel when the power company has the meter pulled.

This sounds like a problem for the guy with the mechanical room key.

[Steve Barker LT]

Sounds like an open neutral feed. Call the P&L co.

[mrchips]

[Pete C.]

Not impossible, but not likely given the symptoms. Usually when 240V appliances are having that kind of effect on unrelated circuits and the other circuits are not out entirely it's a problem with an open neutral. With all 240V appliances off, if it was an open hot leg all the circuits on that leg would be dead.

With an open neutral and 240V appliances off, the 120V appliances on each leg attempt to balance out the voltage between then (a complex and changing series - parallel arrangement) and you will get localized over and under voltage conditions depending on the balance of what is on at the time. Turning on 240V appliances tends to have fairly dramatic effects since they bridge both hot legs and tend to be significant loads.

This can be a dangerous situation both to appliances and to people. The low voltage conditions can damage appliances with motors like refrigerators and the high voltage conditions can of course damage many appliances and can present shock hazards in some cases. Items expecting to see 120V can end up seeing close to 240V depending on how loads balance. Fortunately more and more electronic items are 120/240V auto ranging so they are less likely to be damaged, that still won't save your fridge compressor stalled out trying to run on 80V though.

Since you mention it's an industrial building, I'm suspecting something like an old mill condo conversion? If so, this condition does warrant an emergency call to building management / maintenance.

Pete C.

[Don Klipstein]

This is a big warning sign! Draw more power/current and lights brighten rather than dim? Big warning sign of a big "open neutral" problem!

The problem is big - it can result in 120V appliances getting a lot more than 120V. Some 120V appliances have some significant chance of catching fire before blowing a fuse at "just the wrong voltage" higher than 120 but lower than 240.

The solution is to know where your main panel and any subpanels are, open the doors and identify the neutral bus in each of these items, and grab a plastic-handle screwdriver and take it to the screws on the "neutral bus" and see if any of them are easy to screw in a tightening direction (clockwise), and make any loose ones "thumb-and-index-finger-tight" (or tighter than that if your fingers/hands are on the weak side).

If that does not solve the problem or if you are not up to this, then call in an electrician.

If the problem should end up being upstream of your electric meter, then in most jurisdictions you should be able to get the electrician bill sent to your electric utility company.

- Don Klipstein ( [e-mail])

[Big Al]

Could someone explain how an increase of current on a 240 volt circuit can change the neutral? This would be the result of one of the 120 volt circuits having a heavy load with a leaking neutral. One side would have low voltage and the other side would have high voltage because the neutral is "pulled" to one side.

Al

[mm]

How can a bad neutral keep the 240 volt oven from working, when the oven doesn't have a neutral?

[barry]

How about: by affecting control circuitry, which may well be 120v? Besides, with the totally random set of loads possible, all sorts of things can happen. BTDT. Meanwhile, disconnect all loads possible until situation is rectified.

Regardless, overarching problems first, and an open neutral is a very serious threat.

J

[Big Al]

The control circuit can't draw much current. If it's really a 240 volt oven, what could the control current be? Half amp?

Al

[terry]

. Considered in isolation can understand the question. But; because there are likely to be other 120 volt loads connected between the neutral and either leg of the incoming supply. Also possibly other customers also fed from that same centre tapped distribution transformer. If the neutral is open (or high resistance etc.) the voltage on one or both of the 120 volt legs could be floating around at weird voltages? Also some cooking appliance do use the neutral to power 120 volt timing clocks and other control circuits. The one thing in this house that doesn't use the neutral at all is the electric hot water heater tank. Every other 230 volt appliance has the neutral extended to it.

[Chris Friesen]

There are lots of 240V things that don't have a neutral; central air, electric furnace, assorted shop tools, electric heaters, etc.

Chris