VFD Incoming Cables

[Electriman]

I am sizing a cable to feed the VFD from MCC. Does it need to be shielded? I know that the outgoing cables from VFD to the motor are better to be shielded. But what the VFD input cables? Any NEC requirement?

 

[petersonra]

I am sizing a cable to feed the VFD from MCC. Does it need to be shielded? I know that the outgoing cables from VFD to the motor are better to be shielded. But what the VFD input cables? Any NEC requirement?

I am not convinced that shielded cables on the line side of a VFD are appropriate. How far back are you willing to run them? Back to the service point?

As for the cabling to the motor, well there are a bazillion such installs out there with just regular wire that work fine, and have worked fine for decades. I don't know that there is any objective evidence that suggests that routine use of VFD cables over regular wires serves any beneficial purpose for most applications.

 

[Electriman]

I am not convinced that shielded cables on the line side of a VFD are appropriate. How far back are you willing to run them? Back to the service point?

As for the cabling to the motor, well there are a bazillion such installs out there with just regular wire that work fine, and have worked fine for decades. I don't know that there is any objective evidence that suggests that routine use of VFD cables over regular wires serves any beneficial purpose for most applications.

It is less than 100' between MCC and VFD.

I have not seen any article in the code to prohibit us to use normal cables for incoming and outgoing cables. I however, have seen manufacturers' recommendations to use shielded cable for VFD outgoing cable.