MV Cables - Equipment Grounding Conductor

[NickParker]

1. Do I have to run a separate equipment grounding conductor along with MV Cables as per NEC if the cable is armored?
2. Do I have to run a separate equipment grounding conductor along with MV Cables as per IEC if the cable is armored?

 

[dpc]

What type of "armored" cable? For NEC, in general, yes.

 

[waross]

Most types of armor are not acceptable for use as a grounding conductor.
Spiral armor is particularly bad.
Many years ago it was acceptable for use as a grounding conductor.
It was found the over time a slight amount of corrosion would cause the current to follow the spiral instead of passing straight across the joints between turns.
There were a few instances where a long run was faulted and became a spiral heating element.
Other types of armor may not have this problem but there is still the question of ampacity ratings.
Most codes require a grounding conductor to be rated and approved for a specific ampacity.
Armor is not tested nor is it rated as to ampacity.

Nick: 1. Do I have to run a separate equipment grounding conductor along with MV Cables as per NEC if the cable is armored?
dpc: For NEC, in general, yes.

There may be exceptions for special cables, but I am not aware of any.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[NickParker]

My case:
1) The Medium Voltage cable is manufactured according to IEC and it is armored (GSWA - Galvanised Steel Wire Armored)
2) The breaker (Medium Voltage NEMA Switchgear lineup) feeding the above cable is manufactured as per NEMA
3) The Power cable sizing is done per IEC

If I have to size the equipment grounding conductor (PE in IEC land), what is the code I have to follow?
If NEC - I would use NEC 250.122
or
If IEC - What is the code/rule I have to follow