Electrical Voltage Increase


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Old 12-06-06, 12:13 PM
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Electrical Voltage Increase

Bought a 1500w electric heater for my daughter's room. Lights got brighter when we turned it on. Then her stereo quit and one of the flourescent lights quit as well. Checked voltage and found 119.8v at the outlet. After turning on the heater, that outlet went to 145v. I had expected a bit of a drain on turning on the heater. What am I missing?
 
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Old 12-06-06, 12:21 PM
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Did you plug the heater into a receptacle on the same circuit as the lights and the stereo receptacle?
 
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Old 12-06-06, 12:26 PM
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the whole room is on the same circuit. outlet #1 125v heater on or off, outlet #2 that the heater is plugged in to 125v heater on or off, outlet #3 119v heater off 145v heater on, outlet #4 119v heater off 145v heater on
 
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Old 12-06-06, 12:56 PM
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Originally Posted by wab63
Bought a 1500w electric heater for my daughter's room. Lights got brighter when we turned it on. Then her stereo quit and one of the flourescent lights quit as well. Checked voltage and found 119.8v at the outlet. After turning on the heater, that outlet went to 145v. I had expected a bit of a drain on turning on the heater. What am I missing?
You have the beginning of an open neutral. Get it check quickley or you could damage you equipment. With an open neutral the voltage on one leg can rise to 240 volts while the other leg is zero. Right now you are some where in between.
 
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Old 12-06-06, 01:50 PM
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> After turning on the heater, that outlet went to 145v.

You have an open neutral somewhere in your electrical system, and it should be fixed sooner than later. If the open neutral condition persists it can cause very expensive damage to the appliances in your house.

Do the lights ever get brighter elsewhere in the house or is it confined just to one circuit? If the whole house is affected, you need to call the power company to come check the service; most will do so for free. If they do not find anything, then you should have an electrician check out the main panel connections.

If this is confined to just one circuit, I suspect you have an open neutral on a multi-wire circuit. The solution for this problem would be to open up all receptacles, switches and fixtures on this multi-wire circuit, checking all connections of the neutral conductors, and remaking or tightening any loose ones.
 
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Old 12-06-06, 02:01 PM
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I agree with the others. You have a serious problem. Do not use this space heater, and be careful what you do use.

Call the power company now. Have them check the outside service. If they find a problem outside they will fix it right away. If they don;t find a problem, they may help you find the problem closer to your panel. They may even fix it, depending on what it is.

Do not delay, call them now.
 
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Old 12-06-06, 02:53 PM
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Outlet can't be on the same circuit as the heater and go up in voltage. I think you will find it is a multiwire circuit with a neutral connection problem.
 
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Old 12-06-06, 03:10 PM
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The main cause of the problem you describe is back stab outlets(not back wire clamps). It is a spring contact that weakens over time, then overheats and you lose contact with either the neutral or hot, more often the neutral. Start by replacing all the outlets on that circuit with commercial grade outlets, NO BACKSTAB.
 
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Old 12-06-06, 11:52 PM
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It does sound like an open “shared” neutral, either the service neutral or on a multiwire branch circuit. An open service neutral would affect the whole house.

While backstab connections are prone to failure, in a multiwire circuit the continuity of the neutral is not permitted to depend on device connections. Therefore, unless the circuit was grossly miss wired, a failed backstab would not be the cause.

As others have said, start with your power company.

The increase in voltage could be on the same circuit as the heater if the open was in the service neutral. The increase in voltage would have to be on the same circuit as the heater if a multiwire neutral was open. Wouldn’t the voltage depend on where the measurement was taken in relationship to the loads?
 

Last edited by Juhl; 12-07-06 at 09:10 AM. Reason: typo
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Old 12-07-06, 05:47 AM
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OK I misread the original post. I thought the heater was staying at 119 and the stereo was going up to 145. It seems the heater also went up to 145v. Then it is likely an open neutral in the service. Call POCO ASAP and turn off all double pole 240 volt breakers.
 
 

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