Shop Wiring Dilemna

[John Sanford]

Problem: 2 120v Circuits, 9 receptacles each, running parallel and sharing a neutral. Both circuits are on GFIs. Neither circuit works, immediately tripping the breakers.

In need of suggestions for solutions on tracking down and correcting the problem.

IF the problem is simply the shared neutral, what are the +/- of my potential solutions. I CAN get a 240v/20a GFI for this panel if necessary, if that would solve the problem.

TIA.

[Dave Hammelef]

The shared neutral is the problem, I think the 240 circuit breaker would solve the problem becouse all current flow would be accounted for.

Dave

[Jason Roehl]

Yep. The shared neutral is the problem. GFI's work by measuring the current going through the hot and compare it with the current in the neutral. If they are off by more than 5mA, the GFI trips. So your two circuits are sensing each other's current (it's either canceling by phase or adding if their in phase), creating a huge current difference as seen by the GFI. The 240 GFI breaker sounds like the way to go if you can find one.

Jason