MV Power cable Shield Grounding
MV Power cable Shield Grounding
(OP)
For MV power cables you can ground the cable shield as follows:
+ Single Point.
+At Both Ends
+Transposition
For single point grounding I have noticed that certain vendors refers to a safe value of 25V for the open end side of the cable circuit. So the side were shield is grounded the potential between the shield and the ground is 0 Volts, but at the other end ( open end) you have a value different from 0 Volts but cannot exceed 25V . Can someone please advise were does the 25V threshold come from????.,
+ Single Point.
+At Both Ends
+Transposition
For single point grounding I have noticed that certain vendors refers to a safe value of 25V for the open end side of the cable circuit. So the side were shield is grounded the potential between the shield and the ground is 0 Volts, but at the other end ( open end) you have a value different from 0 Volts but cannot exceed 25V . Can someone please advise were does the 25V threshold come from????.,






RE: MV Power cable Shield Grounding
RE: MV Power cable Shield Grounding
RE: MV Power cable Shield Grounding
This value will determine whether or not under fault conditions (ie high fault current flowing in conductor producing high shield open circuit voltages) the cable sheath will puncture to earth from this high voltage (for a short period of time until the protection operates hopefully).
Safety wise, generally the open end of the shield should not be exposed to personnel when in service as it will produce a potentially lethal voltage for that short time.