15kv vertical ductbank

[meppm]

I am currently working on a project where the 15kv encased concrete ductbank (4-5"Conduits) runs horizontally thru parking garage, reaches shaft location, then concrete ductbank runs vertically for 10 floors, exits shaft and runs horizontally until it reaches electrical room (15kv primary switchgear)

Has anyone ever installed a "exposed concrete ductbank"? (i.e.; garage)
Has anyone ever installed a "vertical ductbank"?
Can vertical conduits be in a dedicated fire rated shaft? (In lieu of concrete)
Code?

Thank you in advance for your responses

 

[jdsmith]

I am currently working on a project where the 15kv encased concrete ductbank (4-5"Conduits) runs horizontally thru parking garage, reaches shaft location, then concrete ductbank runs vertically for 10 floors, exits shaft and runs horizontally until it reaches electrical room (15kv primary switchgear)

Has anyone ever installed a "exposed concrete ductbank"? (i.e.; garage)
Has anyone ever installed a "vertical ductbank"?
Can vertical conduits be in a dedicated fire rated shaft? (In lieu of concrete)
Code?

Thank you in advance for your responses

Dedicated fire shaft for all of the cables or individual shafts? What happens if you have a cable fault? A cable fault in a duct bank will likely weld the cable to the conduit and you have to pull new cable in a different conduit but it will not damage the other cables. A cable fault in cable tray, wire trough, or a dedicated fire rated shaft would destroy other cabels in the vicinity. I haven't seen it myself but I heard the stories from the field techs that saw the aftermath of a failed 15 kV cable in cable tray earlier this year.

I'm in a refinery and all of our duct banks are underground, generally reinforced concrete, and horizontal. I can't help you with code issues very much because we have design criteria that are far beyond the code, but these are some of the reliability concerns that I would have with your installation.

 

[KevinVost]

I am currently working on a project where the 15kv encased concrete ductbank (4-5"Conduits) runs horizontally thru parking garage, reaches shaft location, then concrete ductbank runs vertically for 10 floors, exits shaft and runs horizontally until it reaches electrical room (15kv primary switchgear)

Has anyone ever installed a "exposed concrete ductbank"? (i.e.; garage)
Has anyone ever installed a "vertical ductbank"?
Can vertical conduits be in a dedicated fire rated shaft? (In lieu of concrete)
Code?

Thank you in advance for your responses

Is the concrete encasement designed to have the conductors considered "outside of the building" because they are SE conductors and the main switch is located so far above grade? Or is it just for protection or fire rating? There may be an easier installation method, depending on the situation.

Also to be considered is how you will support the weight of all that MV wire as it rises the 10 floors (table 300.19A/size of the wire), since it sounds like you won't have any pull points.

Much like jdsmith, I am in an industrial plant, and all of our 15kv is in the ground/horizontal in banks, and we have "way beyond code" design/install requirements. (so I've been told by our contractors)

 

[weressl]

Is the concrete encasement designed to have the conductors considered "outside of the building" because they are SE conductors and the main switch is located so far above grade? Or is it just for protection or fire rating? There may be an easier installation method, depending on the situation.

Also to be considered is how you will support the weight of all that MV wire as it rises the 10 floors (table 300.19A/size of the wire), since it sounds like you won't have any pull points.

Much like jdsmith, I am in an industrial plant, and all of our 15kv is in the ground/horizontal in banks, and we have "way beyond code" design/install requirements. (so I've been told by our contractors)

Intermediate vertical supports are in order. Consult the cable manufacturer how much unsupported lengths do they recommend and don't forget allowance for thermal expansion either.