Cable spacing

[cmathew]

Is there any derating factor that can be used when using 500MCM cables? I am currently running 27 cables to a breaker, but I would like to minimize the spacing to less than 100% spacing. IS this possible?

 

[davidbeach]

Sure, but it lowers the ampacity of the conductor and increase the number of conductor, resulting in more total space required. There is a reason that the ampacity in tray with proper spacing is higher than the ampacity in conduit.

 

[cmathew]

Would you happen to know which table in the CEC would have these derating factors? I mean with respect to spacing?

 

[waross]

Tables
1
2
3
4
5B
5C
5D
Rules
4-004
8-104
12-2210
26-142
42-008
42-016
Appendix B Notes on Rules
4-0004
8-104


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[benlanz]

There are hugh derating factors for adjacent AC cables. I recommend that you contact your manufacturer, ask for applicaiton engineering. They typically have models which they can use to give you a conservative estimate.

Benjamin Lanz
Past Chair of IEEE 400
Sr. Application Engineer
IMCORP- Power Cable Reliability Consultants