Grounding Medium Voltage Feeder

[FaradayFF]

Hi Guys,

I've got a feeder going from 25kV switchgear to a transformer. Do I connect(land) the grounding shield of the cable at the ground terminal of the transformer on one end and at the switchgear ground bus at the other end?

Any help would be appreciated.

Thanks,
EE

 

[jim dungar]

What is the conductor length?
What type of raceway?
Indoor or Outdoor?
Are there surge arrestors?

 

[Hv&Lv]

Hi Guys,

I've got a feeder going from 25kV switchgear to a transformer. Do I connect(land) the grounding shield of the cable at the ground terminal of the transformer on one end and at the switchgear ground bus at the other end?

Any help would be appreciated.

Thanks,
EE

Forget the NEC for a minute. Wouldn’t you want to for redundancy anyway?
if this is CN cable it is a requirement as that is the neutral. I assume if it is CN cable it is going on a wye circuit as it would be a waste of money on a delta. If it’s CN cable is it 1/3 or full?

if it’s a shield only the shock hazard would be decreased by connecting it at both ends,

 

[electrofelon]

My understanding is that with bonding at each end you will have shield currents flowing which can reduce ampacity. Single point doesn't have this issue but OTOH there is more shock potential. Here is an article (I have not attempted to verify the accuracy).

Medium Voltage Cable Shield Grounding – Voltage Disturbance

 

[FaradayFF]

What is the conductor length?
What type of raceway?
Indoor or Outdoor?
Are there surge arrestors?

Hi Jim,
See below:
Conductor length is about 800 ft. The MV cable is routed in PVC conduit in a duct bank. No surge arrestors.

Thanks,
EE