Question for Inspectors

Status
Not open for further replies.
eric9822

eric9822

Senior Member
Location
Camarillo, CA
Occupation
Electrical and Instrumentation Tech
I work in a large industrial facility and one of my responsibilities is to ensure that all installations comply with the NEC. We have a project going on now that includes the installation of a several servo drives and motors. The manufacturer has supplied 75 foot pre-terminated cables for each drive and motor, all of the cables are marked AWM. My position is that these cables cannot be field installed in raceway, cable tray, wireway, etc. The manufacturer and my corporate hierarchy states that the cables are OK because the motors, drives, and cables are UL listed as an assembly AND fall under NFPA79. My rebuttal to that was "If that is true then I should be able to install any UL listed equipment in any manner I choose"; I don't think that is correct. What do you say?
 
I am not an inspector but I agree with your manufacturer and corporate hierarchy.

If the machine is listed as a whole then you may run cables between the equipment.
 
Just a _slight_ disagreement.

I believe that this installation is kosher if the cable assemblies are installed per the manufacturer's instructions and the apparatus _including_ the cable assembly installed per instructions is what the UL listed.

-Jon
 
If a listed product arrives in sections then two things can happen.

1. There are assembly or installation instructions for the installer.

2. The components are marked so that is obvious how it all goes together.

It is possible it slipped through without either. Or there is some little known UL clause exception.

The final answer to your question is to contact UL with your concern. Contact regulatory services here. Explain that you are the "AHJ" for the plant.

https://www.ul.com/auth/regcon.cfm
 
eric9822 said:
I work in a large industrial facility and one of my responsibilities is to ensure that all installations comply with the NEC. We have a project going on now that includes the installation of a several servo drives and motors. The manufacturer has supplied 75 foot pre-terminated cables for each drive and motor, all of the cables are marked AWM. My position is that these cables cannot be field installed in raceway, cable tray, wireway, etc. The manufacturer and my corporate hierarchy states that the cables are OK because the motors, drives, and cables are UL listed as an assembly AND fall under NFPA79. My rebuttal to that was "If that is true then I should be able to install any UL listed equipment in any manner I choose"; I don't think that is correct. What do you say?
Click to expand...

In your post you mention the NFPA79 so I am presuming here that your site has adopted the NFPA79. This is not mandatory to adopt but gains legal status once your site does adopt it. Therefore:

NFPA79 y2007: 12.2.7.3 Appliance Wiring Material. Single conductor or multi-conductor Type AWM shall not be permitted.
Exception: When part of a listed assembly suitable for the intended application, Type AWM shall be permissible.

My 2 cents on this passage:
1st penny: The design should have used shorter AWM cables, landed locally, and then made the long run with decent cable. The industrial environment is harsh therefore 12.2.7.3 disallows.
2nd penny: The machine manufacturer is providing warranty that the components chosen are suitable for the intended application therefore the exception.

If you are still in the quotation phase then push hard for the change; If your project manager already signed off then buck some, let the project manager understand you are unhappy, and move on.

Sadly this passes NFPA79 even though for an industrial environment AWM is cheesy.
 
Thanks for the all the replies. The dilemma I am having is we are not buying a "machine", we have installed plenty of machines that came with AWM cabling used for interconnecting components. We are field installing new servo drives in a field installed enclosure and field installing servo motors on a new machine provided by others. If the entire apparatus was being supplied by one vendor I believe NFPA79 would apply. Since we are building it in the field I believe that NFPA79 does not apply and the servo drive vendor is looking for a loophole. Am I off base?
 
AWM is not typically permitted in an industrial environment due to its soft insulation that is subject to chemical aggression.

A typical industrial plant vibrates continuously turning seemingly round edges into wear points. Place your hand on a bay column and you will feel the vibration. AWM has a particularly short life span under this condition.

Many industrial plants also have machines that use various solvents including oils, synthetics, water, et al that are not typical to residential property. These solvents may make the AWM brittle or spongy.

The intent of NFPA79 y2007: 12.2.7.3 is to keep AWM off the property due to aggressive insulation degradation. The exception clause allows a loophole where for lack of a better phrase -an idiot- can approve unnecessary AWM on an industrial site.

Either persuade the vendor to take the AWM back and bring a real industrial cable or order a replacement cable right now cause you're gonna need it.
3' okay
10' yer pushin
75' are you out of your ...
 
Status
Not open for further replies.
Top