# 3 phase 230 volt panel

I have a 3 phase 230 volt 3 wire panel that has a 120, 120 & 208 volts phase to ground and 230, 230, & 230 phase to phase.The AC guy came and installed a new 208/230 volt 3 phase unit. He measured above voltages and told me since one of the voltages is 208 we have to fix that problem first. Do you think he is right ?
As far as I know since the unit is 3 phase 208/230 volt, we should be OK, could you please advice?

Thanks

Hamlet

 tkrussell Posts: 9,673, Reputation: 3698 Senior Electrical & Lighting Expert #2 Jul 24, 2007, 03:46 AM

While the unit is rated 208/230 volts, what the tech seems to be reading is a voltage imbalance, which the motor can not take too much.

A 3 phase panel should have 120 volts from each phase to neutral, and 208 volts across each phase to phase. Where is the 230 volts coming from? You may have a delta system with a high voltage leg. Is the center leg in the panel marked with orange color?

The power source to this panel needs to be investigated because something seems not right. Is this right from a service or is there a transformer in the building feeding this panel?
 thehamlet1 Posts: 3, Reputation: 1 New Member #3 Jul 24, 2007, 07:24 AM
This comes from city and there are another 3 phase machines are already there working.
 tkrussell Posts: 9,673, Reputation: 3698 Senior Electrical & Lighting Expert #4 Jul 24, 2007, 12:35 PM

Contact the city to learn what the nominal voltage supplied should be. The combination of 208 and 230 volts in one service entrance is very odd. Have them come out and verify the voltage supplied is proper.
 thehamlet1 Posts: 3, Reputation: 1 New Member #5 Jul 24, 2007, 05:49 PM
Thanks

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