Erby Posted April 27, 2014 Report Share Posted April 27, 2014 Any ideas what would cause this, other than a loose connection. There was a 200 Amp Main panel and this 100 Amp Main Panel, both fed direct from the meter. The only thing the 100 amp panel served was the heat pump. Click to Enlarge 42.25 KB Click to Enlarge 66.21 KB Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted April 27, 2014 Report Share Posted April 27, 2014 Looks like a classic loose connection. Quote Link to comment Share on other sites More sharing options...
ghentjr Posted April 27, 2014 Report Share Posted April 27, 2014 If you look at the individual wires you can see that the fried one is not mashed like the clean one. It was time for lunch and they forgot to tighten it. Quote Link to comment Share on other sites More sharing options...
LeePlace Posted April 27, 2014 Report Share Posted April 27, 2014 Is that a neutral conductor or a GEC that is blown apart in the bottom right of the panel? If it is a neutral conductor from the heat pump would the higher resistance on the left line created a load imbalance that would have over loaded a down sized neutral? If it is a GEC, a voltage surge? Quote Link to comment Share on other sites More sharing options...
Mr. Electric Posted April 30, 2014 Report Share Posted April 30, 2014 The wire marked with white tape is actually a ground, not neutral. Should have been bare or green, but the main issue is the loose connection that failed. Agree with Jim. Quote Link to comment Share on other sites More sharing options...
LeePlace Posted May 1, 2014 Report Share Posted May 1, 2014 I was asking about the conductor that is landed at the bottom of the ground buss. The 4 in B4U Close points at it. Quote Link to comment Share on other sites More sharing options...
Erby Posted May 1, 2014 Author Report Share Posted May 1, 2014 Perhaps you can see it better without the water mark. Click to Enlarge 39.34 KB Quote Link to comment Share on other sites More sharing options...
Jim Port Posted May 1, 2014 Report Share Posted May 1, 2014 That looks like the braided ground from the SER cable Quote Link to comment Share on other sites More sharing options...
Speedy Petey Posted May 10, 2014 Report Share Posted May 10, 2014 The wire marked with white tape is actually a ground, not neutral. Should have been bare or green, but the main issue is the loose connection that failed. Agree with Jim. That white IS a neutral. There is a separate ground run to the ground bar. Quote Link to comment Share on other sites More sharing options...
Speedy Petey Posted May 10, 2014 Report Share Posted May 10, 2014 That looks like the braided ground from the SER cable I hate to correct you Jim, but the bare wire in SEU is typically a neutral, and in this case it is connected to the neutral bar. That bonding jumper is there because this is a main breaker. Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted May 10, 2014 Report Share Posted May 10, 2014 I see three service entrance conductors inside conduit coming into the rear of the box - no cable there. At the bottom of the box, an SE cable runs to the heat pump. The heat pump requires no neutral, so the braid is being used as an equipment grounding conductor. A jumper runs from the neutral terminal to the accessory grounding terminal bar. The only function of this accessory bar seems to be to accommodate the sideways J-shaped wire that goes to the bonding bushing. I don't see any grounding electrode conductor, which I would have expected to see. Quote Link to comment Share on other sites More sharing options...
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