I have a metal junction box with a main feed. If the ground wires touch the metal box the breaker pops and the ground wires spark. The main feed comes out of a ceiling light fixture box. The ceiling box is two wire BX. I'm using NM to feed the junction box. I grounded the NM to the light fixture mounting stud. Poor ground? Wires touching?
More details...coming out of the junction box I feed a switch for ceiling lights and a feed to a bathroom combo switch. The ohm meter tells me everything is correct at the bathroom combo switch. Everything works perfect. Except when the ground wires touch the metal junction box. Any ideas please?