Fluidized Thermal Backfill (FTB)

[TimK]

I just read up on FTB and it seems like we are putting the cart before the horse. Putting a concrete encasement to keep the conduits and wire cool? It seems as though we are going about this backwards. If heat is an issue, do you not increase the wire size for the ampacity to keep it cooler? I understand that it is mostly a medium voltage requirement, but just started bidding a job wanting it on all conduits in the joint trench, Comm, TV, MV, and Street lighting. Any insight to turn my mind around?

 

[TimK]

FTB

FTB

I read on it in Transmission and Distribution World, the article was labeled "Underground Cables Need a Proper Burial". tdworld.com/mag/power_underground_cables_need/

 

[Fulthrotl]

I just read up on FTB and it seems like we are putting the cart before the horse. Putting a concrete encasement to keep the conduits and wire cool? It seems as though we are going about this backwards. If heat is an issue, do you not increase the wire size for the ampacity to keep it cooler? I understand that it is mostly a medium voltage requirement, but just started bidding a job wanting it on all conduits in the joint trench, Comm, TV, MV, and Street lighting. Any insight to turn my mind around?

that TV cable can get pretty hot.....
i've never heard of it before....
sounds like a solution in search of a problem

 

[TimK]

A/C

A/C

I was wondering if we actually got the duct bangers to connect an A/C vent right into our panels if there would be a need for derating any more? Just let it flow through all of our conduits and everything.

 

[iwire]

If heat is an issue, do you not increase the wire size for the ampacity to keep it cooler?

I imagine costs.