44kV customer owned substation and service entrance panel bonding jumper

[Ekitha]

If the customer owns a 44kV substation with ground grid and runs a ground wire to the main switchboard in the building do we still need a service ground(ground rods) to be installed adjacent to the building? Can’t we remove the bonding jumper and use the station ground grid as the service ground?

 

[waross]

I have two thoughts;
1. Any ground potential rise, step potentials and touch potentials on the 44 kV side will be transferred to the building bonded surfaces.
Think lightning strikes or a primary line contacting the steel work.
2. I understand that the grounding rules have changed or are changing in Canada.
I didn't purchase the latest edition of the code, but enough questions have come up that I was about to order a current code book.
Then I found out that the 2021 Edition will be out in early January and decided I can wait a couple of months longer and get the latest edition.
Check the current code and talk to the AHJ.


Bill
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"Why not the best?"
Jimmy Carter

 

[Ekitha]

You raised a very good point. However, per code rule 10-212 service switch is the primary fuse where neutral of the transformer is grounded. So there after isn't it necessary that grounding conductor must be carried to the buildings mainboard (no bonding jumper between neutral and ground in the board).