Cable Sizing

[nightfox1925]

I had posted a thread before if the NEC ampacity tables can be used for sizing low voltage and medium voltage XLPE multicore cables and there were no reponse. Hence, I am posting the same for the second time hoping for an answer. Thanks to all...

GO PLACIDLY, AMIDST THE NOISE AND HASTE-Desiderata

 

[davidbeach]

I don't know of any reason why the applicable table wouldn't apply. Which table depends on various factors, all of which are given in the table descriptions, find the right one.

 

[nchrista]

You have to be careful to use the low voltage tables for low voltage and medium voltage tables for medium voltage. Not all cables are created equal. Also keep in mind that the XLPE cable is not an NEC type. The NEC just provides a guideline on cable properties. It is left up to the engineer to determine that the cable sheath meets the NEC type, i.e...XHHW OR XHHW-2, etc...

 

[alehman]

There is no table specific to XLPE. The NEC tables are based on the temperature rating. NEC table 310-16 (with its adjustment factors) applies for many low voltage applications. There are columns for temperature ratings of 60, 75 and 90C.

For medium voltage there are numerous tables for different installation methods, with columns for various temperature ratings, and voltages. Again, they are not specific to insulation type.

 

[davidbeach]

Low voltage XLPE would almost certainly be XHHW or some such. Medium voltage XLPE would most likely have an NEC designation of MV90 or MV105.

 

[nightfox1925]

Thanks guys. I will try sizing around 5 cable feeders using the NEC table and a cable manufacturer manual and see whether I get almost similar results and inform this forum accordingly.

GO PLACIDLY, AMIDST THE NOISE AND HASTE-Desiderata