The inductance induced on a 3 phase cable armour

[electrics]

hello, on a 3 phase cable armour is it possible to be induced a voltage ?? if so how can we express this voltage ? on what depends on etc..(mivey I expect nice answers just as till now from you ..) By the way I guess there will be no any voltage induced but a fault or leakage situation might cause it to be so, so is there any formulation to guess the voltage level induced ?

 

[ibew501ed]

wouldn't a fault or leakage current return to its source on the armor as the return path allowing the fields to cancel therefore minimizing any induction?

 

[kwired]

I assume you mean the inductance would be from the conductors within the cable armor. If all the conductors of the circuit are installed within the armor my answer is their magnetic fields will cancel each other out with a net result of no induction on the armor. This is one reason why we are required to install all conductors of a circuit in the same raceway or cable. See 300.3 B

 

[mivey]

As the others have said, without some kind of imbalance that finds an external path, the fields in the cable will cancel each other. Of course, an external field could easily induce a current on the armour.