# Low voltage in half the house



## rstarre (Dec 19, 2008)

he hot wire on one of the electric baseboard heaters came lose and was touching the metal on the back of the heating unit,tripping the circuit breaker. After the wire was correctly reconnected, the ceiling lights were so dim in the kitchen, laundry room, bathroom and half of the living room. If the kitchen lights were on, the lights in the bathroom would not turn on. if you turned off the kitchen lights, only then would the bathroom lights go on. But they were very very dim when they were turned on. I plugged a drill into one of the outlets & it barely ran. The electric power is normal in the rest of the house. I inspected every switch and outlet in the rooms that are effected and found no loose or broken wires. Does anyone have an idea what the cause of this might be? A new electric panel was installed two years ago. Never had a problem until the base board heater blowing the circuit breaker in the box.


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## 480sparky (Feb 1, 2009)

Classic Open Neutral. Call an electrician ASAP.


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## C'est Moi (Jun 6, 2015)

Being that you blew the breaker on the heater I wonder whether you blew the feeder to the panel on one leg. Never seen that happen but I guess it could if the breaker was defective. 

Normally I would agree with Ken above on an open neutral but with the heater situation I am thinking it may not be a phase out

When one phase is out it will only get power when a 240v load is on so that the power is limited because of the resistance of the load and thus the lights don't get up to full brightness. Turn off a load and the other light will get brighter or come on but all of them very dim.

Usually with an open neutral you will blow up a lot of electronics on a particular phase.


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## 480sparky (Feb 1, 2009)

C'est Moi said:


> Being that you blew the breaker on the heater I wonder whether you blew the feeder to the panel on one leg. Never seen that happen but I guess it could if the breaker was defective.
> 
> Normally I would agree with Ken above on an open neutral but with the heater situation I am thinking it may not be a phase out
> 
> ...


A technical correction for anyone reading this: In most residential systems, there's only one phase. Both hots that make up the 240 volts are the same phase.


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## C'est Moi (Jun 6, 2015)

480sparky said:


> A technical correction for anyone reading this: In most residential systems, there's only one phase. Both hots that make up the 240 volts are the same phase.


Now you are confusing me---:laughing: 

Just another technical thought

It is a single phase system but we have 2 phases-so to speak---"A" and "B" . You cannot get 240V between "A" and "A" but you can from "A" to/ "B".

Would you not call "A", phase A and "B" phase B? I would.....


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## Inner10 (Mar 12, 2009)

C'est Moi said:


> Now you are confusing me---:laughing:
> 
> Just another technical thought
> 
> ...


You only have one voltage wave but you can get half the voltage by center tapping the transformer. so A and B are the opposite ends of the same phase...if I understand correctly.


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## tjbnwi (Feb 24, 2009)

Inner10 said:


> You only have one voltage wave but you can get half the voltage by center tapping the transformer. so A and B are the opposite ends of the same phase...if I understand correctly.


Yes, they're 180º apart. I also refer to them as 2 phases, A+B=2.

Not to be confused with the old 2 phase polyphase systems. I saw a polyphase still in use when I was doing a job in Philly about 16 years ago. From what I understand the poly is still in use in areas and supported by the POCO. 

Tom


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## WarnerConstInc. (Jan 30, 2008)

Yes, 2 phase is still being used. Philly is one area I know of for sure. 

Had a few 2 phase motors come through before.


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## C'est Moi (Jun 6, 2015)

Inner10 said:


> You only have one voltage wave but you can get half the voltage by center tapping the transformer. so A and B are the opposite ends of the same phase...if I understand correctly.


Oh I know how it works but we still call them opposite phases or different phases. I am also aware of the 2 phase system.

Although technically correct it is more confusing to the beginners-- I was just toying with Ken when I said he was confusing me.. I knew what he was saying


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## GettingBy (Aug 19, 2010)

How 'bout:
From a supply with at least two wires, 
if you can only get in-phase or 180-out, 
it is a single phase system
?


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## Mike-B (Feb 11, 2015)

480sparky said:


> Classic Open Neutral. Call an electrician ASAP.


Sure sounds like it.
Check voltage between line and neutral and see if your reading jumps around.


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## GettingBy (Aug 19, 2010)

rstarre said:


> he hot wire on one of the electric baseboard heaters came lose and was touching the metal on the back of the heating unit,tripping the circuit breaker. After the wire was correctly reconnected, the ceiling lights were so dim in the kitchen, laundry room, bathroom and half of the living room.


The heavy current opened a connection that was flaky for a while but never flaky enough to notice except with instruments?

You maybe can have more flaky connections show themselves by shorting the outlets that are most distant from the breakers but a better way is to rent one of Ideal's house wiring analyzers.

Flaky connections will get hot but they are in fire resistant boxes. Right? :blink:

If your 120v, 1200w load reads 60v it means 300w is heating up some connection somewhere. This should char a Wirenut very quickly.


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