I have a equipment (indoor) that needs to be powered up with 4000A feeder (480V/3ph) from 4000A switchgear (outdoor). The equipment comes with a termination box (an enclosure with 4000A bus bar, nothing else) that I can terminate the cables. I have over (20) of them in this set up now and I will have more as the facility grows so I would like to have somewhat economical yet scalable solution I can use for a long term.
I am planning to use a cablebus for this feeder and trying to come up with a way to reduce the feeder size by utilizing the free air ampacity of 310.15(B)(17) to size the cablebus per 370.80. However, I realized that I still had to use table 310.15(B)(16) for the termination rating per 110.14(C).
In order to avoid this termination rating, I am planning to use "4000A busway flange" at the switchgear (directly connecting to switchgear bus) then the other side of the flange, I will have a "busway cable tap box", where I can connect my cablebus. Then this cablebus will be run to the equipment termination box.
That said, I have two questions:
1. Can I size my cablebus with 90 deg C column now instead of 75 deg C? I don't have any CBs or switchgear that I need to worry about.
2. Can I use the 90 deg C column from the free air ampacity table 310.15(B)(17) or still have to use the 310.15(B)(16)? Am I still under temperature limitation per 110.14(C)?
I am planning to use a cablebus for this feeder and trying to come up with a way to reduce the feeder size by utilizing the free air ampacity of 310.15(B)(17) to size the cablebus per 370.80. However, I realized that I still had to use table 310.15(B)(16) for the termination rating per 110.14(C).
In order to avoid this termination rating, I am planning to use "4000A busway flange" at the switchgear (directly connecting to switchgear bus) then the other side of the flange, I will have a "busway cable tap box", where I can connect my cablebus. Then this cablebus will be run to the equipment termination box.
That said, I have two questions:
1. Can I size my cablebus with 90 deg C column now instead of 75 deg C? I don't have any CBs or switchgear that I need to worry about.
2. Can I use the 90 deg C column from the free air ampacity table 310.15(B)(17) or still have to use the 310.15(B)(16)? Am I still under temperature limitation per 110.14(C)?