I just did a job for a customer where the lights in his house will actually get brighter when a motor or a load is turned on. And it can happen from any circuit in his house. What is actually happening is some how voltage is jumping from phase A to Phase B in his panel. I tried everything I know and still cant fix this problem. I know it has to be a neutral somewhere but want to ask my fellow electricians out there for some help. Do you think it is a problem with the power company's neutral in their transformer or in this guys house? Thank you
1. Identify a receptacle on phase A. Label it receptacle A.
2. Identify a receptacle on phase B. Label it receptacle B.
3. Turn off all breakers except those serving receptacle A and receptacle B.
4. Unplug everything in the house.
5. Plug a 1800W heatgun or microwave oven into receptacle A.
6. Plug a 40W incandescent into receptacle B.
7. Plug a voltmeter into receptacle B.
8. Turn on the heatgun and the light and watch the meter.
9. If you see a voltage exceeding 130V across the bulb then measure between phase B and neutral in the service panel. If you see the same high voltage then it is either a power company problem or neutral is disconnected or burned in the panel.
10. If you see the correct voltage then the problem is in the house.