Grounding requirements for MV splice box

[philly]

I'm looking for any guidance and NEC references for requirements for grounding of a medium voltage splice box.

Application is MV cables ran in PVC conduit through a metal splice box. There is no individual EGC as part of the circuit as the concentric shieled on the cables are being used as the EGC. The splice made within the box is completely covered by the insulated splice including the cable shield.

My understanding of the NEC is that all splice boxes need to be bonded to the EGC for a path back to source. Since in this case the PVC conduit does not serve as EGC and the cable shield EGC is not accessible under the splice is there another approved means of meeting NEC requirement for box grounding?

It has been suggested that driving a ground rod to local earth and connecting to box will suffice as adequate grounding?

Looking for any input and NEC references that may be helpful here.

 

[synchro]

Can you use MV cables with a concentric neutral for the EGC, or are the cables already bought / in place?

 

[philly]

Can you use MV cables with a concentric neutral for the EGC, or are the cables already bought / in place?

Cables do have concentric neutrals however cables are already in place and already spliced with shield/neutral contained within the insulated splice and not accessible inside the box.

 

[ron]

250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes. If circuit conductors are spliced within a box or terminated on equipment within or supported by a box, all equipment grounding conductor(s) associated with any of those circuit conductors shall be connected within the box or to the box with devices suitable for the use in accordance with 250.8 and 250.148(A) through (E).

 

[electrofelon]

I agree there is no exception allowing the box to be unbonded. So this must be like a copper tape shield that is suitable for use as an egc? I am not really familiar with such things but it seems like there must be some sort of kit that allows you to splice a lead on to the shield?

 

[JoeStillman]

Is this indoors or outdoors? I never run MV cables in PVC unless it's outdoors, where all splice boxes are concrete.

250.86 Exception No. 2 might apply.

Exception No. 2: Short sections of metal enclosures or raceways
used to provide support or protection of cable assemblies from
physical damage shall not be required to be connected to the
equipment grounding conductor.