Assuming you are not joking, I believe we are supposed to be looking at the area of contact (or the lack of it) between the bottom contacts of the disco. The bare conductor is likely that way because of it.I assume we are supposed to be looking at the bare conductor and that it is not a corner grounded system?
That's the upper left, incoming L1.Assuming you are not joking, I believe we are supposed to be looking at the area of contact (or the lack of it) between the bottom contacts of the disco. The bare conductor is likely that way because of it.
That's the upper left, incoming L1.
The pic is rotated. Allow me:The way the picture is oriented when I see it there are three disco blades on a vertical bar. The bottom two blades appear to have rotated on the shaft they are attached to so that when the top blade is fully engaged, the middle one has a somewhat reduced area of contact and the bottom one has a drastically reduced area, and the conductor connected to the bottom one has gotten so hot that the insulation has been burned off.
All righty, then. Substitute "left" for "bottom" in all I wrote.
The way the picture is oriented when I see it there are three disco blades on a vertical bar. The bottom two blades appear to have rotated on the shaft they are attached to so that when the top blade is fully engaged, the middle one has a somewhat reduced area of contact and the bottom one has a drastically reduced area, and the conductor connected to the bottom one has gotten so hot that the insulation has been burned off.
Good chance that insulation cracked and then flaked away? Pretty sure I have seen that before with XLPE insulation types. THHN melts and drips away if it stays hot for long enough.That’s similar to what I was thinking. But I looked at it as the other two poles were opening, but the phase C pole was not, and it was a corner grounded system so current kept trying to flow in phase A because of some load situation, burning that blade. But on second thought, there wouldn’t (shouldn’t) be a fuse on that corner ground, and it would/should be B phase, not A. So your scenario makes a lot more sense.
Odd though that there is not more heat damage to the other conductor insulation given that the A phase completely burned away. Not even ashes left?
Read post #7.Odd though that there is not more heat damage to the other conductor insulation given that the A phase completely burned away. Not even ashes left?