Arc Flash Hazard Label

[bthielen]

Re: Arc Flash Hazard Label

Ryan_618,

You are correct. As a manufacturer we do affix an arc flash warning label as required by the NEC and as you indicated it only warns of the danger and does not provide any specifics.

The labeling that spells out the appropriate PPE, which I believe is defined by NFPA-70E and required by OSHA, needs to be the responsibility of the end-user of the machinery because as Charlie pointed out there is a lot of information and research required in order to determine what PPE is required. In addition, end-user facilities and power supplies are in a constant state of change. Even if an analysis could be done at the time of machine development, it is probably safe to say that it would be obsolete by the time the machinery is actually installed. And then, what's to say nothing will change in the future that would have an affect on the required PPE.

This is one area I can understand the labeling. A label that provides information that can be used such as PPE required, is good because this can vary from place to place. A label that generally warns of arc flash is unnecessary because this is an inherent danger in most any electrical application and electricians know this. It's like installing a label on an electrical panel that says, "There is electricity in this panel." No kidding!

Bob

 

[rbalex]

Re: Arc Flash Hazard Label

Originally posted by charlie b:
...
Why is there a dusty spot in my memory that tells me a label has to state the amount of energy available (in units of "calories per square furlong" or something), and that specifies the minimum PPE required to perform live work on the equipment?
...

As I said in my original response, that WAS the content of the original Proposal. As it was watered down, the word-smithing simply overlooked that the remaining text still required "field installation." This may be a good opportunity for a simple Proposal to have manufacturers apply the label as an alternate.

What is often overlooked though, is OSHA (Fed or State) can require the labels to be affixed to existing installations NOW; so field application is still necessary.

 

[goodcode]

Re: Arc Flash Hazard Label

Send in those proposals to change the NEC!
The closing date is coming soon, Novermber 4, 2005.
Be sure to address your ideas on the number of labels for large equipment.
Remember the amount of available short circuit current will most likely change (increase) during the lifespan of an electrical system.
Perhaps we can include the speed of the upstream overcurrent protective device on these labels along with a new text that requires the installation of a new label on downstream equipment if the upstream device is ever replaced. This would be a great help to the end user as the calculation would only require determining the amount of available short circuit current. With these two items known, the speed of the OCPD and the amount of ASSC the user can properly apply the hazard risk category tables in NFPA-70E.
The commenters in this forum ask questions, share problems and argue (nicely) what are essentialy controversial issues, new requirements or requirements that are not user friendly and need to be addressed. The result of these discussions are excellent ideas for proposals to change both the NEC and NFPA-70E.
Send those proposals!

 

[ryan_618]

Re: Arc Flash Hazard Label

Originally posted by goodcode:
Send in those proposals to change the NEC!

I have already drafted my 110.16 proposal.

 

[iwire]

Re: Arc Flash Hazard Label

Originally posted by ryan_618:
I have already drafted my 110.16 proposal.

How many proposals for 2008?

 

[ryan_618]

Re: Arc Flash Hazard Label

I don't know...40 or so?

 

[realolman]

Re: Arc Flash Hazard Label

We have a 100 hp, and a 150 hp air compressor in one area of the plant, and a 50 hp in another about 50ft away all fed from the same mcc.

These are turned on/off in whatever combination production requirements warrant.

Would these affect the available fault currents at the mcc or equipment fed from the mcc?

[ October 03, 2005, 06:29 AM: Message edited by: realolman ]

 

[charlie b]

Re: Arc Flash Hazard Label

Originally posted by realolman:Would these (motors) affect the available fault currents at the mcc or equipment fed from the mcc?

Yes. When a fault occurs, a motor will lose its source of power. But it is still spinning. So it becomes a generator for a very short time, and adds to the amount of current available at the point of the fault.