Conduit Fill for MV Cables

[LibertyEngineering]

Good Day,
Does the NEC contain a chart for maximum number of MV105 EPR Cables based on wire size or is it necessary to do a Circular Mils calculation for the 40% fill? I suppose another method would be to check General Cable, Southwire or Okonites web site to see if they have documentation regarding their cables listed.
Thank You

 

[LibertyEngineering]

Update - I found a calculator on Southwires web site that works nicely. Only issue I found is you can not select bare conductor for the ground. Can the ground conductor have THHN insulation in in the same conduit with 15kV EPR cable? Still curios in the NEC offers this as well but I assume there are too many variables to consider to make a common chart.

 

[don_resqcapt19]

Update - I found a calculator on Southwires web site that works nicely. Only issue I found is you can not select bare conductor for the ground. Can the ground conductor have THHN insulation in in the same conduit with 15kV EPR cable? Still curios in the NEC offers this as well but I assume there are too many variables to consider to make a common chart.

The EGC is permitted to be bare, but a lot of specs that I have seen required it to have 600 volt insulation.

As far as chart, there is no one, as there is no standard OD for those types of conductors like there is for the 600 volt conductors. You have to use the published physical specifications of the conductor from the manufacturer or find a calculator from the manufacturer.

 

[LibertyEngineering]

Thanks Don - I figured there was no NEC chart after I posted my original question for the exact reason you quoted. The 600V insulation on the ground is interesting though because it is in the same pipe as 15kV cable. Your permitted to have cables of different voltages in the same conduit provided the insulation on all of them matches the highest voltage in the conduit. Likely since its not a current carrying conductor this does not apply but did find it interesting to note. Which is why I was looking for the bare copper ground. Then I figured if it fits the max 40% fill with insulation it will certainly fit the max 40% fill without.

 

[mkgrady]

Years ago I would see specifications for four conductors to have the same insulation. The fourth one being a grounded conductor. These were jobs where the engineering was done as a low bidder. I always ignored the requirement for the ground to be insulated and shielded at the same rating as the phase conductors and just used 600 volt insulation for the grounded wire. It would have been ridiculous to have stress cones and ground shield tails on the grounded wire.

 

[LibertyEngineering]

Very true mkgrady, very true