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I have 3-phase power hooked up to my building. I also have solar panels feeding the grid. Most of the power in the building is functioning normally. I tested the phases with a multimeter and got 120 - 125 V per phase.

In the electrical panel for a certain part of the building the phases with the same multimeter are giving me 180 V, 180 V, and 40 V respectively.

I'm hooking up a contactor relay switch that activates a pump, and the 180 V burned out one switch already, so I tried running some wires from a panel where the phases are indicating the normal 120 V, but at the end of the wire I'm getting 180 V in each phase. I can't figure out what could be making the voltage increase or leak from one phase to the other.

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    \$\begingroup\$ Lost neutral plus a single-phase load? \$\endgroup\$
    – hobbs
    Apr 4 at 1:02
  • \$\begingroup\$ Measure the three phase voltages to earth ground, as well as neutral. Also perhaps check current in each phase. Probably open neutral or poor connection to earth ground. \$\endgroup\$
    – PStechPaul
    Apr 4 at 1:16
  • \$\begingroup\$ An excellent occasion to check the terms of your "electronics insurance", if any. \$\endgroup\$
    – greybeard
    Apr 4 at 6:37

1 Answer 1

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If the voltage between phases is correct (208 V), or close to it, then the neutral has become disconnected.

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