Electrical Utility Cable Failure

[ghostbuster]

These overhead 3/0 cables melted through and caused a subsequent electrical failure within a nearby building.The lost production cost was over $400K. for this one facility.The electrical load from this one facility is 400-475 amps.The utility repaired these cables as per the picture enclosed.Any comments?(please have patience, I am trying this picture paste program for the first time)

 

[celtic]

These overhead 3/0 cables melted through and caused a subsequent electrical failure within a nearby building.The lost production cost was over $400K. for this one facility.The electrical load from this one facility is 400-475 amps.The utility repaired these cables as per the picture enclosed.Any comments?(please have patience, I am trying this picture paste program for the first time)

I took the liberty of rotating your first image and slightly reducing the second to make the text easier to read..hope you don't mind.

 

[LarryFine]

Is it possible that the panel failure caused the overheads to melt?

 

[mdshunk]

Are you questioning the quality of the utility quadplex repair, and the associated paralled conductors for the repair section? Looks like a pretty typical patch job by a trouble truck, until another crew can be secheduled to run a new quadplex. I feel pretty good about saying that they don't intend to leave it this way. It's probably on their books for another day to perform the permanent repair.

 

[ghostbuster]

Is it possible that the panel failure caused the overheads to melt?

Larry
Approx. 3 weeks earlier to this failure, one 3/0 overhead phase conductor melted in the same location.They repaired it using 2-#6 parallel conductors(good for approx.200 amps).That lasted for 3 weeks before melting and causing this 3 phase failure to occur.They now decided to use 3 instead of 2 #6 per phase(according to the utility that is the only size wire on the repair truck).Don't forget my customer is allowed to draw up to 500 amps from this overhead .There are also other customers on this same overhead feeder.

My customer elected not to have another $400k catastrophe and rented a diesel generator until the proper repairs could be done (approx. 3 weeks on diesel)

 

[LarryFine]

Well, you gotta tell us these things. :smile:

I am curious as to how loss of one phase caused such damage.

 

[augie47]

failure

failure

Well, you gotta tell us these things. :smile:

I am curious as to how loss of one phase caused such damage.

Likewise!
Just from the pics, it almost looks like a fault in the gear. I wouldn't challange any "expert" but my guess would have been a fault in the disconnect causing a subsequent conductor failure.