Duct Bank Rebar Traverse/Lateral Ties and Circulating Currents

[Amex12]

What is the general thought on lateral ties in duct bank arrangements that encircle the entire group of conduits? Would this cause heating in the duct bank and if so how would one model this in an ampacity calculation?

 

[cranky108]

First, I have never seen this done, as we use fiberglass for re-enforcing for primary duct banks.

May not be much help for existing banks, but may be helpful for anything new.

 

[7anoter4]

If sum of all currents is zero no current will be induced in this grounding strip.
Usually in case of slight current unbalance the circulating current is unsignifying.