Bain Posted June 12, 2009 Report Share Posted June 12, 2009 So I looked at a panel this afternoon, and the cables connected to the left terminal bar were charred and the insulation was melted in varying degrees. Thing is, though, all the wires connected to the right terminal bar were pristine. I realize the cables in the photo are probably just loose, but it isn't logical that the installer got everything nice and tight in the right terminal bar, and then was totally careless when he got to the left bar. Any other possible explanations? Click to Enlarge 46.1 KB Quote Link to comment Share on other sites More sharing options...
Bill Kibbel Posted June 12, 2009 Report Share Posted June 12, 2009 Any other possible explanations?No. In my experience, it's usually because of loose connections. I'll bet that electrician forgets to tie one of his shoes on occasion. It's probably the left one. Quote Link to comment Share on other sites More sharing options...
Richard Moore Posted June 12, 2009 Report Share Posted June 12, 2009 I would guess you just had the one loose connection. The subsequent arcing at that point was enough to heat up the bus bar locally and char and melt the other close-by wires. The damage seems to get less as you get further away from the worst of those near the bottom of your photo. Quote Link to comment Share on other sites More sharing options...
Bain Posted June 12, 2009 Author Report Share Posted June 12, 2009 Ah . . . interesting. If that's the case, I'll bet it was the stranded 8-gauge wire. It had some yucko melted insulation. Quote Link to comment Share on other sites More sharing options...
asihi Posted June 12, 2009 Report Share Posted June 12, 2009 Any other possible explanations?No. In my experience, it's usually because of loose connections. Loose connections will definitely create high resistance, but couldn't a shared neutral do this as well? Quote Link to comment Share on other sites More sharing options...
msteger Posted June 12, 2009 Report Share Posted June 12, 2009 So I looked at a panel this afternoon, and the cables connected to the left terminal bar were charred and the insulation was melted in varying degrees. Thing is, though, all the wires connected to the right terminal bar were pristine. I realize the cables in the photo are probably just loose, but it isn't logical that the installer got everything nice and tight in the right terminal bar, and then was totally careless when he got to the left bar. Any other possible explanations? Click to Enlarge 46.1 KB It was probably a Friday afternoon install. Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted June 19, 2009 Report Share Posted June 19, 2009 Any other possible explanations?No. In my experience, it's usually because of loose connections. Loose connections will definitely create high resistance, but couldn't a shared neutral do this as well? An improperly shared neutral will heat up along its entire length, not just at the connection point. As a general rule, if you see heating at a connection point, it's because the connection is or was loose. - Jim Katen, Oregon Quote Link to comment Share on other sites More sharing options...
dnoel Posted June 22, 2009 Report Share Posted June 22, 2009 So I looked at a panel this afternoon, and the cables connected to the left terminal bar were charred and the insulation was melted in varying degrees. Thing is, though, all the wires connected to the right terminal bar were pristine. I realize the cables in the photo are probably just loose, but it isn't logical that the installer got everything nice and tight in the right terminal bar, and then was totally careless when he got to the left bar. Any other possible explanations? Click to Enlarge 46.1 KB Apprentice installer? "This is how you do it..." -Does it right a couple times "Ok got it!" Quote Link to comment Share on other sites More sharing options...
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