Arc Flash Hazard Label

gabany · Sep 22, 2005

I am in a debate about wether EVERY door on an MCC needs labelled with the Arc Flash Hazard label (complete label including flash hazard boundary, cal/cm^2, FR class,, etc..). OR will a label at the main, or even the top of each section suffice.
NEC 110.16 is not clear on this issue, but there are some (especially label salesman) who insist that every single bucket door be labeled.
This is at an industrial plant where only trained personel will be opening the electrical gear.
Thanks

zog · Sep 22, 2005

Re: Arc Flash Hazard Label

That is a good question. I have always interpreted it like your label salemen, each bucket or breaker cubicle should have its own label.

Now I will confuse you even more. Say you have a switchgear lineup with a main and 4 feeders. The main breakers clearing time will determine the arc flash hazard for all five breakers for racking. However, if you are closing a feeder breaker, the clearing time for the feeder breaker will determine the arc flash hazard, so do you label the feeder breaker based on the feeder breaker settings or the main?

I believe the higher hazard should be reflected on the label, but many plants have done the opposite.

IMHO all 5 breakers in this senerio should be labeled based on the main breakers clearing times.

rbalex · Sep 22, 2005

Re: Arc Flash Hazard Label

It's difficult to see how it could be interpreted as a requirement to apply it to individual cubicles or compartments when it is the inclusive terms "Switchboards, panelboards, industrial control panels," and "motor control centers" that are used.

More to the point, absolutely nothing in the original Proposal (which was even more onerous) or the "accepted" Comments even hinted at such a requirement.

The original Proposal (as accepted by CMP 1) wanted specific marking indicating the actual cal/cm2 @ 18". In that case, it is?conceivable (but it still wasn't mentioned) that individual markings per cubicle/compartment may be?reasonable. IMO that's when the "label manufacturers" jumped on the band wagon and overlooked how watered down the Proposal actually became.

petersonra · Sep 22, 2005

Re: Arc Flash Hazard Label

IMO, this whole thing has been overblown to the point of insanity. when presumably competent people cannot even agree on a decision on something this simple, it seems to me the requirement needs to be re-evaluated.

maybe it is a good idea to label things as having a flash hazard, but the fact is that anyone that has any reason to open these boxes up in the first place ought to know that there is an inherent hazard in doing so.

someone who does not know what an arc flash hazard is, will not care and ignore the warning label anyway.

maybe we should start putting labels on objects weighing in excess of 3 pounds warning that if they are dropped on a foot it can cause injury.

or on bridges warning people that jumping off them into the water is hazardous.

bphgravity · Sep 22, 2005

Re: Arc Flash Hazard Label

It may sound counter-intuitive, but it is probably best to provide as little information as possible. Provide a warning that an Arc Flash Hazard exists and leave it up to the individual and/or company how to handle it.

You don't want to provide inaccurate information that could lead the person to assume less of a risk or even more of a risk than really exists. This could lead to protective measures not suited for the danger or could make the protective measures unnecessarily bulky and cumbersome for the task at hand.

charlie b · Sep 22, 2005

Re: Arc Flash Hazard Label

I agree with Bryan. The computer I am using to type this comment was obsolete the moment it came out of the box. The same is true with any label you install, for its information can not be relied upon the moment after the label is in place. It is far better to provide the simplest of warnings, with no specifics that are not explicitly required by the code.

This concept is what I like to call "precision ambiguity." You know what is not being said, and why it is not being said, and how far your reader can go with what is being said. This is not an attempt to deceive. Rather, it is an attempt to prevent a future reader from becoming deceived by old information on an old label.

It's like the old adage that was not finished, in its original published form: "A man with two watches does not know the time." The idea is that the two watches can never show the exact same time, and the wearer will not know which is right. But that adage needs to be extended, as follows: "A man with two watches does not know the time. But a man with only one watch is more likely to deceive himself into believing he knows the correct time, for he will trust the one and only indication that is in his possession."

So the future electrician will see an "old" label (defined as having had its glue dry), will deceive himself or herself into believing what the label says, and will select the wrong PPE.

[ September 22, 2005, 03:54 PM: Message edited by: charlie b ]

pierre · Sep 23, 2005

Re: Arc Flash Hazard Label

Geez Charlie, I thought this was an electrical forum. I feel like I just had a session with a shrink

gabany · Sep 23, 2005

Re: Arc Flash Hazard Label

Thanks for the replies, and I'd have to say I completely agree with everything I just read.

realolman · Sep 24, 2005

Re: Arc Flash Hazard Label

A label on the door of electrical panels telling electricians there is an arc hazard places the responsibility on the employee ( I told him it was dangerous ) without the employer having to actually provide any useful information. To elevate nonsense like this to the status of a legitimate safety effort, as if it were a protection for workers, is outrageous.

[ September 24, 2005, 07:40 AM: Message edited by: realolman ]

bthielen · Sep 26, 2005

Re: Arc Flash Hazard Label

I have a hard time believing that any label at any time shifts the responsibility to the employee.

In today's society where nobody is held responsible for themselves, the employer, machine installer, manufacturer, and anyone else that can be found to be remotely involved with the design, purchase, installation, and operation of the machine will be held responsible before the actual individual.

I believe labels today have evolved to only serve maybe three purposes:
1. As a reminder for the trained/qualified individual of a hazard that he/she should already be aware of.
2. As a warning (to make them think twice) to untrained/unqualified individuals of a potential hazard in an effort to avert a disaster.
3. Because of the over-use of labels...no practical purpose at all is served. Machinery today is so cluttered with these things, they are all but ignored completely.

Bob

petersonra · Sep 26, 2005

Re: Arc Flash Hazard Label

Originally posted by bthielen:
I have a hard time believing that any label at any time shifts the responsibility to the employee.

3. Because of the over-use of labels...no practical purpose at all is served. Machinery today is so cluttered with these things, they are all but ignored completely.

Bob

On the first point you are completely correct. There is no such thing as being able to shift responsibility from the employer to the employee. The warning label MIGHT be able to shift some responsibility away from the manufacturer though.

I agree completely on cluttered up machine thing. It is just like instruction manuals have gotten. They are so full of notes, warning, and cautions that it is hard to find any real information in them.

[ September 26, 2005, 11:32 AM: Message edited by: petersonra ]

realolman · Sep 26, 2005

Re: Arc Flash Hazard Label

I just think the whole concept of a label warning electricians about what they already know is inane.

I wonder if there are any regs concerning the accuracy or scope of machine manuals themselves.

If machine info and drawings were accurate and complete, it would often preclude anyone having to get in a panel in the first place.

Now that would be useful. A genuine safety enhancement.

[ September 26, 2005, 05:15 PM: Message edited by: realolman ]

ryan_618 · Sep 26, 2005

Re: Arc Flash Hazard Label

Originally posted by bthielen:
3. Because of the over-use of labels...no practical purpose at all is served. Machinery today is so cluttered with these things, they are all but ignored completely.

Bob

What ever do you mean? The surgeon general has a warning on every pack of cigarettes...haven't you noticed nobody smokes anymore?

ryan_618 · Sep 26, 2005

Re: Arc Flash Hazard Label

Oh, and by the way...why does this signage have to be "feild" applied? Does having it "factory" applied make it less safe?

I don't like this requirement either...but I write it up every time I do an inspection.

charlie b · Sep 26, 2005

Re: Arc Flash Hazard Label

Originally posted by ryan_618: Oh, and by the way...Does having it "factory" applied make it less safe?

As you well know, the factory is not going to know the details of the installed configuration, so they can't tell what label to affix. But then, neither does the designer, for the selection of equipment comes after the construction bid is won by a contractor. For that matter, the installer cannot know exactly how the system will be operated (e.g., which large motors will be running at any given point in time), and certainly would not know if the utility were to have made a significant change to the transmission and distribution system parameters after the design drawings had been issued. Therefore the installer cannot tell what amount of arc fault current will be available at the panel. In fact, any number of changed conditions will impact the requirements for PPE.

Therefore, the only thing that is reasonable, which is to say, "reasonably accurate," is for the technician who is about to work on the panel to do the following:

Ascertain all facts about the installed configuration,

Ascertain all facts about the operational conditions,

Obtain the applicable system parameters from the utility,

Perform a calculation,

Determine the appropriate label,

Affix the label,

AND THEN:

Read the label to learn what PPE to use.

Or am I just getting cynical in my old age?

ryan_618 · Sep 26, 2005

Re: Arc Flash Hazard Label

Originally posted by charlie b:

Therefore, the only thing that is reasonable, which is to say, "reasonably accurate," is for the technician who is about to work on the panel to do the following:


Ascertain all facts about the installed configuration,



Ascertain all facts about the operational conditions,



Obtain the applicable system parameters from the utility,



Perform a calculation,



Determine the appropriate label,



Affix the label,

AND THEN:


Read the label to learn what PPE to use.

Or am I just getting cynical in my old age?

The label doesn't have to contain any of that information.

"WARNING: ARC FLASH DANGER" Would satisfy the code rule. Why can't the manufacturer do that?

realolman · Sep 26, 2005

Re: Arc Flash Hazard Label

The label doesn't have to contain any of that information.

"WARNING: ARC FLASH DANGER" Would satisfy the code rule. Why can't the manufacturer do that?

Why should anybody? It's useless.

charlie b · Sep 26, 2005

Re: Arc Flash Hazard Label

OK, Ryan. What I had been thinking about must be outside the scope of the NEC.

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 far as the "useless" nature of the label, how about we make a label that just says, "Don't Sue Me," and leave places for the manufacturer, the designer, the installer, the operator, and the owner to sign?

realolman · Sep 26, 2005

Re: Arc Flash Hazard Label

how about we make a label that just says, "Don't Sue Me," and leave places for the manufacturer, the designer, the installer, the operator, and the owner to sign?

I LIKE IT!

It's honest, and doesn't pretend to be something it's not... The beginning of change for the better!

bphgravity · Sep 26, 2005

Re: Arc Flash Hazard Label

Here's my favorite label:

LAWYER OPPORTUNTIY ZONE
Failure to have perfectly adequate warnings that anticipate every possible hazardous situation, no matter how remote, will result in litigation by hordes of lawyers who will make even the most innocent thing appear to be malicious intent by your company to cause great harm to their client, and will leave you penniless and broken after wasting immense amounts of your time.

www.safetylabel.com

Arc Flash Hazard Label

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