Derate conductors

[RES87]

Hi I’m installing a 14kw Generac generator wanted to know if I can run all my wires from main panel to 100 amp 16 circuit Generac transfer switch panel in same conduit? I know if the whip is less than 2’ there’s no issues but if more than 2’ does the regular 15Amp/20Amp circuits and the 100Amp feeder circuit need to be separated in different conduits?

 

[Johnhall30]

Yes if the conduit is more than 24 inches you need to use the derating chart in the NEC to adjust the wire ampacity

 

[Dennis Alwon]

Hi I’m installing a 14kw Generac generator wanted to know if I can run all my wires from main panel to 100 amp 16 circuit Generac transfer switch panel in same conduit? I know if the whip is less than 2’ there’s no issues but if more than 2’ does the regular 15Amp/20Amp circuits and the 100Amp feeder circuit need to be separated in different conduits?

The feeder can be in the same conduit as the branch circuits but de-rating will apply if more than 24" . You can have up to 9 #12 and #14 current carrying conductor's without having the de-rating affect the ampacity. Unless you have multiwire branch circuit then the neutrals will count also if they are moved.

 

[infinity]

Unless you have multiwire branch circuit then the neutrals will count also if they are moved.

Even for a 120/240 system?