Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
Use ohms law and think about it. First, in order for the voltage to go down, you need to have a resistance in series with loads. If you have a resistance on one leg, then you should see a similar drop in voltage between the phase with the resistance and not a drop on the phase without the resistance. That is the first check. After that, if it doesn't matter which breaker you turn on, you still have voltage drop, that means the problem is between the source and the line side of the breakers. Could be panel, could be incoming wires. Keep using Ohms law and logic.