Ground Conductor Depth

[opty]

I have a grounding system where I have multiple ground rods tied together with a #2 bare tinned solid conductor by exothermic connections. The ground rods are between 10-20 feet apart. I am not using the ground conductor as a grounding electrode but as a mean of providing an equipotential ground system. Since the ground conductor is not a grounding electrode then it does not have to be buried 30" below grade or below frost line. I am actually thinking of laying the conductor on the subgrade covered by nylon fabric and pea gravel.

Does anyone have any comments on my interpretation of the NEC and my installation method?

 

[Dennis Alwon]

I have a grounding system where I have multiple ground rods tied together with a #2 bare tinned solid conductor by exothermic connections. The ground rods are between 10-20 feet apart. I am not using the ground conductor as a grounding electrode but as a mean of providing an equipotential ground system. Since the ground conductor is not a grounding electrode then it does not have to be buried 30" below grade or below frost line. I am actually thinking of laying the conductor on the subgrade covered by nylon fabric and pea gravel.

Does anyone have any comments on my interpretation of the NEC and my installation method?

I don't believe the nec specifies any depth for that install.

 

[jghrist]

This sounds similar to the grounding grid in an outdoor substation. The main purpose is to reduce step- and touch-voltages. If the grid spacing is significant (larger than a step), then burial at a lower depth may result in lower step- and touch-voltages. Typically, a substation ground grid will be buried 18 inches below grade. Normally, a larger conductor (2/0 or 4/0) would be used as well for better physical durability.