Electrical – Why does the food truck trip GFCI outlets only when a grounded cord is used

electricalgfci

I have a food truck with a 60 amp service installed. When I plug into a GFCI with an ungrounded cord it works fine. But when I plug into GFCI with grounded plug it trips immediately. Please help.

Best Answer

GFCI's work by measuring the current going out on the hot wire and the current coming back on the neutral. If there is more than ~5ma of current difference they trip.

So, if it does not trip when you use the 2 wire cord and then trips with a grounded cord, that tells me your equipment or cord has a problem. If it trips with just the cord with nothing attached to it, then the cord seems to be the problem and you should try another cord.

If a piece of a equipment has a ground fault problem and is leaking current to the ground wire, then a two wire cord continues to work, while a three wire cord allows the current to leak to ground and trips the GFCI.

This is a dangerous situation and should be corrected immediately. That is the purpose of the GFCI. It tells you when your equipment has a problem. Repair it now.

Good luck!