Ground (earth) Continuity Conductor, insulated? bare?

[Power0020]

I have read IEEE-575-2014.

Couldn't find specifications for ECC insulation. Some local standards in Middle East ask for 600/1000 V insulation, for corrosion protection only.

Such voltage level will breakdown in case of induced voltages (Due to source substations GPR) exceeding 1 kV and protect the sheath externally (sheaths usually tolerate upto 5 kV).

However, if a remote circuit fault return current is crossing the cable route somewhere and voltage gradient starting to appear around the cable, the ECC may not function is reducing the gradient if too far from the cable?.

But, on other hand, if we left it bare it may cause transferred voltages to appear along the route? safety hazard? we will end up with a MV cable to protect cables terminiating with source substations with high GRP (rocky, with many OHTLs)

Any clues?

 

[7anoter4]

I have only the 1988 edition of IEEE 575 and in 5.4.3 Parallel Ground Continuity Conductor it is stated:
“The parallel ground continuity conductor is usually insulated so as to avoid any corrosion risk and it will be subject to voltage induction from the power cables in the same way as any other parallel conductor.”
Transposition will mitigate only the built-up induced voltage but will not diminish the potential transfer. If it is about a long cable, in my opinion, multiple groundings will be required.