Ductbank

[gadero]

I've seen multiple designs for concrete encased ductbanks. Have see a copper ground wire cast in a ductbank a couple of times, but not sure why this was done.

What is the technical reason for including a bare copper ground wire in a ductbank?

Thanks

 

[dpc]

As a ground wire. The bare copper in contact with moist concrete makes an effective grounding electrode. It helps tie the ground grids together at each end of the duct bank.

 

[tinfoil]

At our utility, it also gives us something to trace for undergound locating of a ductbank that does not yet have any cables in it.

 

[AusLee]

if it was run outside the ductbank, then maybe it will be subject to getting cut in future site works. The concrete protects it.

still, i would be careful: if the duct bank is not correctly moulded, then the concrete may break and cut the cable.