AnsweredAssumed Answered

Table 310.16 vs. Article 400 for a 3-conductor VFD cable?

Question asked by pwk@kraemerkoating.com on Sep 23, 2020
Latest reply on Sep 26, 2020 by chiefns830

Hi,

 

I am working on a project in which I will be using a VFD to drive an AC motor.  For the motor power cable from the VFD to the motor, I am planning to use a cable with a braided shield that is specifically intended for use with VFD's.  The cable will have three current carrying conductors and one ground conductor.  Table 310.16 in the 2020 NEC lists the ampacities of of "insulated conductors with not more than three current carrying conductors in raceway, cable, or earth."  As my VFD cable will have three current carrying conductors, this makes me believe table 310.6 *might be* where I should look to determine what wire size (AWG) I should get for the cable conductors.

 

What confuses me is that article 400 covers the ampacities of "flexible cords and cables".  It is unclear to me for my application whether I should be consulting table 310.16 or if I should be consulting Article 400.  The VFD cable I will be using is "flexible" in that I am able to bend it (specifications list the minimum bend radius as 7.5 x cable diameter).  In my application, however, it will not be required to flex or bend during use.  The cable will be routed from the VFD to the motor as necessary and secured in place before the machine is put into service.

 

With this being the case, for the purpose of determining the required size (AWG) for my conductors, should I be looking at table 310.16 or Article 400?  Any advice will be greatly appreciated.

 

Thanks and best regards,
Paul

Outcomes