ECN Forum Forums General Topics of the Trade General Discussion Area Unexplained voltage

May be it's just that it's Monday, but I'm still a little confused.

What is your primary system - 480 delta or 480Y/277?


You say you are measuring a voltage from the "neutral to the equipment ground conductor". By this do you mean from the control transformer "neutral" to the control panel ground? Or do you mean from the control panel neutral to the building ground?

As, I said, my head is a little fuzzy this morning so I don't know if this is going to be valuable. Could I get a couple of more voltage readings? (Grid is your 480 system, CPT is from your control transformer)
480 grid phase A to grid neutral
480 grid phase B to grid neutral
480 grid phase C to grid neutral
480 grid phase A to grid ground
480 grid phase B to grid ground
480 grid phase C to grid ground
480 grid phase A to panel ground
480 grid phase B to panel ground
480 grid phase C to panel ground
480 grid neutral to grid ground
120 panel hot to grid neutral
120 panel hot to grid ground
120 panel neutral to grid ground
120 panel neutral to panel ground

Also what happens when you lift the ground connection from the control transformer.

Hi all
Here’s what we finally found almost seems anti-climatic. It seems that the hot and neutral were reversed at the faceless GFCI. Should have known better and checked that in the beginning. Oh well at least we found the problem and all is well.
Thanks for all your replies
Rich

mama said there'd be days like this....

thanks for the update Rich....