Roof A/C wiring

[Bill Staley]

The circuit breaker for our rear roof A/C tripped and won't stay engaged.  I disconnected the AC supply at the A/C unit and the breaker still tripped.  Indicates there is a short in the wiring between the breaker and the unit,   I'm hopping there is a junction box somewhere between the breaker and the unit.  Has anyone had this happen to them or does anyone know if and where a junction box might be?  Need to get this fixed...in Nashville where the temp has been in the mid to high 90s with high humidity.

[Steve Huber Co-Admin]

Bill,
I'd start by removing the load wires and seeing if it will stay closed. If not, bad breaker. If it does stay closed, check for chafing where the wires enter the AC unit and where they exit the breaker box. Can't help as to junction box but not sure why one would be employed if that AC is only load on the breaker. Diagrams of 03 Pats show dedicated breakers with direct line from breaker to AC.
Steve

[Bill Staley]

Followup to my original post.  Found the problem in a junction box located in the return air duck in the ceiling.  Had to remove the panel attached to the ceiling and that revealed the air ducts. 

There is a metal junction box where the wires from the breaker and the wires from the unit are tied together.  They apparently had vibrated loose and gotten hot.  They were all welded together.  Trimmed off the burn parts, cleaned everything up, tied them back together, and all is working as it should.