Panel Question

First post here - thanks already for the great info.

I am having trouble finding what I think should be common info. We build "machines" here - and associated "industrial control panels." It's clear these panels should have an Arc Flash label of some sort (per NFPA).

Typical analysis for level of risk includes "available current" for the calculations. Since I usually do not know where or how my panel will be installed, how can I know this info?

Is there a "generic" label I should be using? The "worst-case" label might make routine maintenance impractical.

I hope this post makes some sense! It seems like this would be a common question, but I haven't found the solution yet, so here we are...

Thanks for your help.

Generic Label

I think the only prudent thing for you would be to affix a generic label in accordance with NEC 110.16. That is pretty much the standard for OEM manufacturers (SqD, Cutler etc.) that I see in the field. The labels can be bought at Grainger, Brady, or pretty much any electrical wholesale house. I believe it is the company's responsibility to assess their equipment. If you are going to install your equipment (in other than dwellings), you will need to follow the safe work practices outlined in the NFPA 70E and wear the appropriate PPE (God forbid you're doing it energized)!

The arc hazard labels cannot be installed by the manufacturer. As you point out, the manufacturer has no way of determining fault current, let alone incident energy. Generic labels have been applied by manufacturers, but these do not meet the requirements of NFPA 70E-2009. You could provide labels with blanks to be filled in by the customer, but there is no standard format. The format would be different depending on whether or not an IE analysis is performed.

Thanks for the quick response.

So - to be clear - as a manufacturer, I am not required to label this equipment. But furthermore - I am not able to assess the risks anyway, unless I visit my machine in the field. This assessment and labeling, then, falls to the end-user.

Is that about right?

Yes, it's the duty of the end user. You cannot do it (your equipment can be installed elsewhere, the upstream distribution system can be updated). And a generic label with "Don't work live" is still insufficient per NFPA 70E (no Cat and no IE listed).

What you should (must?) put on a label is the AIC your equipment can withstand (along with nominal voltage, amperage, # of phases, frequency, etc.). Note it's not even your duty to verify that end users expose it to something smaller (unless you make it a warranty issue: expose it to too much short-circuit current and the warranty is gone).

Hope it helps you!

Agree with Vincent totally, but depending on the standards that apply to your equipment you may need to do more from a mfg. perspective.

Thanks again, that's all great info.

I do indeed already include all the (previously NEC required) label information (voltage, current...).

The question really arose for two reasons:

a) I've noticed the arc flash label on the competition's machines;
b) The customer asked me to put it on.

I'm thinking "a" is a direct result of "b," but that's really not important. What matters to me is that I do the right thing, and I believe I am, and you have all reinforced my conclusion.

Thanks again!

You should just put a simple label that meets the NEC 110.16 requirements, like this one.

No arc flash lable may be required, but as a panel builder you may be required to place a label on the panel that contains information below.

Manufacturer name
Supply voltage, phase, frequency, and
full-load current
Short Circuit Current Rating (SCCR)
Enclosure Type

This site has some good panel info. You may already know this but I figured I would throw this out there.

http://www.moeller.net/binary/ver_techpapers/ver959en.pdf