Plumber gets wacked cutting water line

[fisherelectric]

I was working in house when the plumber cut the main water service line and got a nasty shock. Some lights got dim...some got brighter and a plug-in type surge arrestor on the first floor burst into flames. Blackened the wall up to the ceiling above the outlet.
Turns out the insulation on the old SEC cable had rotted away where it came through a masonry wall and the neutral braid had oxidized away completely. The cable looked fine where it entered and exited the wall. Looked as though it had been that way for quite awhile.

 

[GoldDigger]

I was working in house when the plumber cut the main water service line and got a nasty shock. Some lights got dim...some got brighter and a plug-in type surge arrestor on the first floor burst into flames. Blackened the wall up to the ceiling above the outlet.
Turns out the insulation on the old SEC cable had rotted away where it came through a masonry wall and the neutral braid had oxidized away completely. The cable looked fine where it entered and exited the wall. Looked as though it had been that way for quite awhile.

A definite hazard of having too good a GES. It keeps the neutral failure from showing up while the voltage offset associated with it is still small.

 

[jusme123]

 

[kwired]

Will a non-contact voltage detector pick up this condition if used before cutting the pipe?

No, for same reasons it doesn't pick up anything when testing an intact neutral conductor. Only after you open the connection back to the source (cutting the pipe, disconnecting a union) do you see a rise in voltage to ground, and it will detect that.