5Kv Conduit Fill

[luckylerado]

Are the rules for calculating conduit fill the same for 5kv conductors?

Must GRS be used rather than EMT for 5kv?

I have a drawing with 3" Rigid specified for 2 #8AWG 5kv conductors.

 

[roger]

For the general rules see part II of article 300.

Roger

 

[don_resqcapt19]

The percent fill does not change with voltage. There are additional cable/conductor minimum bending radius limitations that apply to 5 kV installations.

In general the code permits the use of EMT for medium voltage applications, but if the drawing calls for rigid, even over sized rigid, that is what you need to provide unless you take exception to the specs in your proposal.

 

[Strathead]

Are the rules for calculating conduit fill the same for 5kv conductors?

Must GRS be used rather than EMT for 5kv?

I have a drawing with 3" Rigid specified for 2 #8AWG 5kv conductors.

The 2-#8 doesn't really tell us a lot. Many medium voltage situations use shielded conductors, and the Engineers sometimes spec out 15 K or even 35K rated cables. Other times they are cables with multiple conductors under a single shield. So what you really need to know is the quantity and the outside diameter or area of the cables to calculate fill.

 

[luckylerado]

... So what you really need to know is the quantity and the outside diameter or area of the cables to calculate fill.

I figured up a 1" was the min EMT size for 2 of these conductors.

OD of the conductor is 0.38 inches.

This is a design build job and before I questioned the 3" with the EE, I wanted to make sure I was not overlooking something glaring in NEC that would have mandated the 3" GRS

Thanks for the input.