Multi Substation LV Earth Grid Connection

[dodgeybro]

Hi guys,

I'm on a new greenfield plant and was discussing earth grid bonding with our electrical contractor. We have 10 13.8/380v substations servicing different areas of plant, each with a substation earth grid, and each area of plant has an earth bonding grid. For me it would be normal to link each of the substation earth grids and plant earth grids together, which is reflected in the design drawings, but our contractor disagrees that this is standard and has asked for a direction from the client. Is there any reason not to join the earth grids across plant?

Thanks.

 

[kingpb]

No reason you shouldn't, it will lower the total grid resistance which decreases the maximum grid potential rise.

I would say transferred potentials would be your greatest concern that could cause the ground potential rise to be exceeded.