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Connecting galvanized steel grorunding grid to copper grid

Connecting galvanized steel grorunding grid to copper grid

Connecting galvanized steel grorunding grid to copper grid

I am designing a solar plant with a galvanized steel grounding grid, the plant will be connected to collector substation some 2 km away, cables will be cross bonded so the two facilities grounding grids are electrically connected through cable sheath.

The collector substation is made of copper, I doubt that, when connected, the galvanized steel grid will be subject to galvanic corrosion.

Any clue?

RE: Connecting galvanized steel grorunding grid to copper grid

Connecting the grids with the cable sheath is a bad idea and contrary to some codes.
A cable sheath is not normally approved nor suitable for use as a grounding conductor.
Better to ground the sheath at the supply end and insulate the load end.
You do not need to interconnect grounds 2 km apart.
Allowing fault current to pass on the cable sheath may melt the sheath.
With the sheath grounded at both ends you may have an issue with induced currents heating the sheath.

"Why not the best?"
Jimmy Carter

RE: Connecting galvanized steel grorunding grid to copper grid

According to IEEE 575 IEEE Guide for the Application of Sheath-Bonding Methods for Single-Conductor Cables and the Calculation of Induced Voltages and Currents in Cable Sheaths 5.4.3 Parallel Ground Continuity Conductor
You have a parallel ground continuity conductor grounded both ends.
This cable will carry out the maximum presumable short-circuit current. The size of this conductor must be adequate to carry the full expected fault current for the cable system.
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.
The connection between this cable and the galvanized steel is done in the same way as equipment grounding conductor to the equipment frame-usually with copper -aluminum lugs.
See for instance also:

RE: Connecting galvanized steel grorunding grid to copper grid

Girds will be connected once the cable is cross-bonded or even through a continuity conductor.

During normal operation, there is a galvanic cell between the two grids, similar to the one formed by steel pipelines and other metals underground, I fear that will cause the less noble metal to corrode, i.e. the galvanized steel grid.

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