Overloded Neutrals

[broadgage]

I suspect that several of the neutrals were so loose that they become very hot under normal load, perhaps they were never tightened at all when first installed, mistakes do happen.

They may well have been tightened later, after the heat damage but before your visit.

I doubt that connecting both legs of the service to the same hot would do this, although the current in the neutral of a MWBC would be doubled, I doubt that #14 loaded to 30 amps would get THAT hot (over here, 2.5mm, similar to #14 is ALLOWED to carry 25 amps, and fairly regulary misused on 32 amps, it does not get that hot!)

And even if an overloaded neutral DID get that hot, I would expect damage along the whole length of the cable, not just at the ends.

 

[Smart $]

In particular it looks like the screw/conductor in the center of the picture was the source of the heating. It has what appears to be arcing marks between the screw and the bus. All of the rest of the damage appears to be from radiated heat, the conductors further away and below the center are not as damaged as those directly above it.

I agree with your analysis.

 

[GoldDigger]

In particular it looks like the screw/conductor in the center of the picture was the source of the heating. It has what appears to be arcing marks between the screw and the bus. All of the rest of the damage appears to be from radiated heat, the conductors further away and below the center are not as damaged as those directly above it.

Everyone repeat after me: "Glowing Connection.":thumbsup:

 

[jim dungar]

Everyone repeat after me: "Glowing Connection.":thumbsup:

:thumbsup:
Just experienced one on my hot tub. I am glad it lasted through the -25?F temperatures before the #6 conductor fused open.hmy:

 

[GoldDigger]

I agree with your analysis.

Added forensic information: Take a good look at how the arc and burn marks on the bar and the screw line up to see whether the screw had been re-tightened before you saw it.

 

[jumper]

There are torque requirements although how many actually follow them.

I do,,,,,,,, but then I work on projects for the DoD/military and the govn't inspector stands there and watches so I gotta. It is a PITA.

 

[Smart $]

Added forensic information: Take a good look at how the arc and burn marks on the bar and the screw line up to see whether the screw had been re-tightened before you saw it.

I cannot determine the alignment from the provided picture... and if the screw has been re-torqued there is no way to know when, other than before the picture was taken.