Mon 23 Jun, 2014 06:51 pm
I have a residential property that has a voltage drop issue. When the utility power is on and all breakers in the panel are OFF, the voltage reads 120 to ground and 240 phase to phase. As you start to turn breakers on the A phase voltage begins to drop. By the time all of the breakers are on the A phase only reads 45 volts and the phase to phase reads 120v.....has anyone ever seen anything like this before? The utility and the underground service has been tested and reads out fine. It has to be something in the panel board or even somewhere in the house. Any ideas would be appreciated.
Usually unbalanced voltage is caused by an open neutral. You need to take your readings from phase to neutral. Did the utility pull the meter and check the meter socket? A little more info would be helpful. Are the breakers in the same panel as the service disconnect or a sub-panel?
Bah's response very logical. Get a voltmeter; measure between neutral and some known ground such as a water pipe. More than a few volts confirms Bah
On the other hand it's also possible that an open circuit or wiring error somewhere has placed an appliance or other load in series with your box