Voltage imbalance
Voltage imbalance
(OP)
Good day,
I have a question on voltage changes in the supply side of some wiring.
One leg that comes into the panel reads 115 VAC the the other 126VAC when no load is applied. The grounds are connected together and connected to an earth ground rod. The neutrals are connected via a bus which are connected to the primary panel via a neutral cable.
When a load (such as a pump or heater) is put onto either of the incoming power legs, the voltage changes to 69 VAC on one leg and 170 VAC on the other leg.
Anyone have a suggestion on where to check? I'm completely stumped.
Thank you.
I have a question on voltage changes in the supply side of some wiring.
One leg that comes into the panel reads 115 VAC the the other 126VAC when no load is applied. The grounds are connected together and connected to an earth ground rod. The neutrals are connected via a bus which are connected to the primary panel via a neutral cable.
When a load (such as a pump or heater) is put onto either of the incoming power legs, the voltage changes to 69 VAC on one leg and 170 VAC on the other leg.
Anyone have a suggestion on where to check? I'm completely stumped.
Thank you.





RE: Voltage imbalance
RE: Voltage imbalance
<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032
RE: Voltage imbalance
RE: Voltage imbalance
Gunnar Englund
www.gke.org
RE: Voltage imbalance
RE: Voltage imbalance
If one leg is drawing more current than the rating of the transformer, it could bring the voltage down to meet the same KVA rating.
Check the neutral line and the KVA rating.
RE: Voltage imbalance
Assuming you really mean NO load, you have a problem with your transformer.
RE: Voltage imbalance
RE: Voltage imbalance
Since the power comes in underground to the step-down transformer, goes to the house panel then to a breaker out to the garage underground via aluminum wiring where the problem is located, are you referring to the step-down transformer? The power in the house is fine - we've checked every circuit.
RE: Voltage imbalance
RE: Voltage imbalance
RE: Voltage imbalance
RE: Voltage imbalance
RE: Voltage imbalance
Do not assume that a tight connection means a good connection, especially when dealing with aluminum conductors. I have personally tested AL compression connections that were open electrically, but physically appeared perfect.
This can be a very dangerous problem, and can effect the proper operation of circuit protective devices. DO NOT attempt to resolve this yourself. This is a problem for someone well experienced with power system issues to correct. Failure to properly correct the problem or problems within this system could have serious consequences for you and your family. Find a professional, and be prepared to bear the cost of replacing at least a portion of the AL wiring system.
Bigbillnky,C.E.F.....(Chief Electrical Flunky)
RE: Voltage imbalance
You really need to get to the bottom of this fast. Furthermore an imbalance could easily translate to a fire in any one of numerous devices normally found in a house.
RE: Voltage imbalance
The aluminum wiring goes from the house panel to the GARAGE where the service is having the problem. All wiring in the house is copper as is the wiring in the garage. The garage is detached from the house - which at this point sounds like a good thing given the issue.
The voltages as far as the hot tub is in the house and are being read from hot to ground. Those are fine at 115.
The only place we read uneven voltages are the garage, starting at the panels where the aluminum wiring comes in, then down the line - lights, outlets, etc.
I believe that the next step is to move a hot leg to the neutral to replace the current neutral. The garage does NOT need 220 running to it.
I'd really like to replace the aluminum wiring from the house to the garage, but since I'm out of work, I'm gonna have to make due.
RE: Voltage imbalance
If you don't see more than half a volt do the same on the garage end.
Let us know what you find.