5KV Testing

[rey-man]

Gents:

We are in a search for a 5kv underground feeder. The contractor dug test pits to expose the ductbanks. We are not certain if the feeders are in the ductbank. We opened a manhole and noticed MV armored cable. The maintenance told us it might be the feeder we are looking for, again no assurance. The contractor choose to turn off the bucket and check with a hot stick. We just found out the stick does not do anything with the armored cable. We cannot shutdown the feeder for a long time.

Does anyone know a way to test if an armored cable is live or not?

As always, thanks for all your comments.

 

[GoldDigger]

Gents:

We are in a search for a 5kv underground feeder. The contractor dug test pits to expose the ductbanks. We are not certain if the feeders are in the ductbank. We opened a manhole and noticed MV armored cable. The maintenance told us it might be the feeder we are looking for, again no assurance. The contractor choose to turn off the bucket and check with a hot stick. We just found out the stick does not do anything with the armored cable. We cannot shutdown the feeder for a long time.

Does anyone know a way to test if an armored cable is live or not?

As always, thanks for all your comments.

Testing whether it is live or not, looking for voltage, will be very difficult, if no impossible.
If the return path for the current is not through a concentric shield, however, you can use a clamp type ammeter to detect current flow.

You would have to check the current with the feeder on and at least some load connected, then turn off the feeder and compare the current reading.
Not 100% definitive though, since the current in other wires may stop for various reasons when the feeder is turned off.

 

[rey-man]

Testing whether it is live or not, looking for voltage, will be very difficult, if no impossible.
If the return path for the current is not through a concentric shield, however, you can use a clamp type ammeter to detect current flow.



You would have to check the current with the feeder on and at least some load connected, then turn off the feeder and compare the current reading.
Not 100% definitive though, since the current in other wires may stop for various reasons when the feeder is turned off.

Its a 3/c cable. Can you use a clamp ammeter around it?

 

[GoldDigger]

Its a 3/c cable. Can you use a clamp ammeter around it?

Only if you make sure to apply an unbalanced (e.g single phase) load to it so that there is net current.
And even then it would have to be a line to neutral load, not a line to line load. That might not be possible.