single phase 120/240 volt residential voltage problem

[Duaneb]

I have a unique problem I have 120 volts to ground coming into panel on each phase and 240 across both. if I run a dedicated line to a outlet plug in a light or battery charger what ver I saw he voltage go to 70-94 volts and even 170 volts if i turn other breakers! what you all think I am stumped

 

[Lucien Nunes]

Sounds like you have a high-resistance connection in the supply neutral. As soon as you put any load on the panel the voltage developed across the faulty connection causes the panel neutral voltage to move towards whichever hot has the most load, reducing the apparent voltage of that leg and increasing the other.

This can be a dangerous situation, as you have found, because excess voltage can be supplied to the outlets. Have it checked by a licensed electrician before attempting further use.

Incidentally, this is a UK forum - we don't have 120/240 power distribution here and most of our electricians will be unfamiliar with it.

 

[Gardner]

Open neutral. Look to see where the break is. You may need to contact the poco since it could be on there side. If your lucky it will be on your side.

 

[Pete999]

Whats poco? only out of interest

 

[Simonslimline]

Whats poco? only out of interest

Power Company i think.

 

[Engineer54]

Lucien, is spot on with his diagnosis, seen this quite a few times over the years. This isn't too rare to find this type of fault in the States and in other countries that use the 3 wire single phase supply system. As Lucien quite rightly states, this is a potentially dangerous situation that needs sorting out on an urgent basis!!

 

[Gardner]

Whats poco? only out of interest

Power company that supplies the electricity to the home. Funny abbreviation.

 

[norcal]

Agreed that it's a neutral problem, call the PoCo & hope the problem is on their side.

 

[littlespark]

6 year old thread. You think the OP has sorted this urgent problem yet?

 

[Megawatt]

I have a unique problem I have 120 volts to ground coming into panel on each phase and 240 across both. if I run a dedicated line to a outlet plug in a light or battery charger what ver I saw he voltage go to 70-94 volts and even 170 volts if i turn other breakers! what you all think I am stumped

Duaneb it sounds to me like there is circuits sharing neutral. When you have the multiple circuits and you cut one breaker off and take the neutral loose you can cause the voltage on the other circuits voltage will fluctuate. Having read what you are saying and you are reading 170vac on a circuits which causes a dangerous situation. If you are reading 240vac phase to phase and 120vac to ground I don’t think it’s the power company problem. Back many years ago you was allowed to share neutrals but now if you have found this it needs to be corrected because it is a code violation. 170vac to ground can fry clocks, microwaves etc, anything that is supposed to be 120vac can be damaged beyond repair. Maybe you need to hire a more experienced electrician.