Is Ignoring Installation Instructions For A Listed Component A Code Violation?

[cowski]

We install breaking resistors with Allen Bradley VFDs. The installation instructions for the resistor instructs you to place a contactor in front of the VFD that will open if a temperature switch in the resistor opens up. They cite a risk of fire.



Would ignoring this requirement be considered a code violation? I'm thinking it violates 110.4(B), right?

I'm thinking:

• "Listed and labeled equipment" applies to the VFD. It doesn't matter whether we're listing our control panel under UL 508A - the VFD is always listed.
• Does "any instructions included in the listing" include the installation instructions? Or do I have to find the listing and see if the installation instructions are specifically referenced?

 

[petersonra]

It uses the phrase "or equivalent".

I usually just wire the overtemp switch into the drive enable. That seems adequate to me.

Is the resistor a listed component? Might only be recognized.

 

[cowski]

Bob - I've been doing that too...

That's a good point - I just checked and the resistor is listed E196302.

 

[zbang]

Because I'm stirring up pots today-
Does putting a contactor ahead of the VFD violate any of the VFD's instructions? (I'd kinda hope not, but I'll ask anyway.) Using the Enable input seems far more sensible.

 

[cowski]

Does turning off the enable input de-energize the DC bus on the drive? I think that's the only way to stop the resistor from lighting on fire after the IGBT fails...

I did ask Rockwell about turning off a contactor to the drive and they said it's not ideal, but if the thermostat opens it's typically after the drive has failed anyway.

 

[petersonra]

Does turning off the enable input de-energize the DC bus on the drive? I think that's the only way to stop the resistor from lighting on fire after the IGBT fails...

I did ask Rockwell about turning off a contactor to the drive and they said it's not ideal, but if the thermostat opens it's typically after the drive has failed anyway.

Good question.