Single Point Bonding Metallic Sheaths of 15 kV Cables

[ThePunisher]

Hi all,

When we do single point bonding of single core 15 kV power cables (in our case), where would the Common Sheath bonding location would be? Is it at the source side of the cable or at the load side?

1. For example, from source transformer secondary to the down-stream switchgear incoming section
2. For example, from the switchgear outgoing feeder section, to a down-stream transformer primary

I normally see the single point grounding on load ends of the cables but don't know the "theory or industry technical reason behind it (unless it does not matter where).

Feel free to provide any site links that may help me.

Your technical guidance is highly appreciated.

Regards,

 

[7anoter4]

In my opinion, the grounding point has to be close to the source and to provide sheath voltage limiter (if it is required) at the far end.
SVLs should always be used if the expected surge voltage level exceeds 75% of the BIL of the jacket or of the shield/sheath sectionalizing insulator.
See IEEE 575/2014

 

[Parchie]

If it can't be helped because you have chosen to bond at a single point only, I'd say bond it at the panel end. There are lots of devices to protect at the panel side. Also, it's easier to left a single point in the panel during troubleshooting and find grounds.

As mentioned, you could use sheath voltage limiters if your having long lines, IMO.