Burnt Ground Wire

[jgromkoski]

What would you say caused this ground wire to burn up?

[Jeffrey R. Wicklander]

Excessive heat.

Are you sure that it is a ground wire and not the grounded wire(neutral) for some branch circuit? It looks like the hot conductor was cut and the branch circuit is no longer used. It may have not been rated for the amount of current going through it.

Jeff

[Robert Meier]

From the photo it's hard to tell what that white conductor was actually doing. Since I see some remnants of a red conductor it could be that the cable had three conductors and the two hot conductors were on the same phase making the current additive in the neutral. Or it could be from something else. Do you know the exact function of that white conductor the way it was hooked up?

[jgromkoski]

Originally Posted by Robert Meier

From the photo it's hard to tell what that white conductor was actually doing. Since I see some remnants of a red conductor it could be that the cable had three conductors and the two hot conductors were on the same phase making the current additive in the neutral. Or it could be from something else. Do you know the exact function of that white conductor the way it was hooked up?

I just assumed (maybe wrongly so) it was connected to grounding cable exiting at the bottom of the panel. In either case there was no grounding connection to the panel. Obviously referred to a licensed electrician.

[Jim Port]

It appears that the panel is fed thru a metallic conduit that could be providing the ground.

The neutral should have been re-identified.

[Robert Meier]

Originally Posted by jgromkoski

I just assumed (maybe wrongly so) it was connected to grounding cable exiting at the bottom of the panel. In either case there was no grounding connection to the panel. Obviously referred to a licensed electrician.

So are you saying that the small white conductor was spliced to the GEC?(big dark conductor) If so then you might have a problem with the system neutral being broken and you now have all of the neutral current flowing on the GEC.

[jgromkoski]

Originally Posted by Robert Meier

So are you saying that the small white conductor was spliced to the GEC?(big dark conductor) If so then you might have a problem with the system neutral being broken and you now have all of the neutral current flowing on the GEC.

I think that is what happened in this case.

[Jeffrey R. Pope, CMI]

Originally Posted by Robert Meier

So are you saying that the small white conductor was spliced to the GEC?(big dark conductor) If so then you might have a problem with the system neutral being broken and you now have all of the neutral current flowing on the GEC.

OUCH. But even worse in this case - that conductor is broken. All of the neutral current will be carried on exposed and bonded components such as the conduit and enclosures.

[Robert Meier]

Originally Posted by jpope

OUCH. But even worse in this case - that conductor is broken. All of the neutral current will be carried on exposed and bonded components such as the conduit and enclosures.

Yes, and if there's an interconnected city water system the neutral current will flow on the water pipe into the neighbors house and return to the utility transformer on the neighbors neutral conductor.

[jgromkoski]

Originally Posted by jpope

OUCH. But even worse in this case - that conductor is broken. All of the neutral current will be carried on exposed and bonded components such as the conduit and enclosures.

I guess in this case it was a "good" thing then that there was no bond to the service panel enclosure.