Arc Flash labeling

[stopsignhank]

Our industrial facility mainly deals with 480 volt and lower. I am labeling the equipment in the shop and I have labeled all the panels and disconnects and the control panels. A couple of questions though.

1. We have a disconnect on a rectifier (we do some electropolishing here) I have put a label on the disconnect. Do you think I need to put a label on the rectifier also? The disconnect is mounted on the rectifier.

2. We have a control panel that controls a 480 volt pump that could be 15 feet away. I have a label on the control panel, do I need a label on the pump also?

3. Would I need to put a label on a mill that is 480 volt?

Thanks for any help.

 

[big john]

Here's what 70E says (emphasis mine):

130.5(C) Equipment Labeling.
Electrical equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers that are in other than dwelling units, and are likely to require examination, adjustment, servicing, or maintenance while energized, shall be ?eld marked with a label containing all the
following information:
(1) At least one of the following:
a. Available incident energy and the corresponding
working distance
b. Minimum arc rating of clothing
c. Required level of PPE
d. Highest Hazard/Risk Category (HRC) for the
equipment
(2) Nominal system voltage
(3) Arc ?ash boundary

So it's a bit of a judgment call. For example, it seems very unlikely to me that a motor peckerhead would be opened while energized, so I would not personally choose to label a pump motor.

Regarding your disconnect and rectifier scenario, since each one might require troubleshooting while energized, I would say they would both need labels. Additionally, because it's conceivable that the disconnect fuses might reduce the incident energy in the rectifier, you might need those two separate labels for accuracy.

 

[wbdvt]

Our industrial facility mainly deals with 480 volt and lower. I am labeling the equipment in the shop and I have labeled all the panels and disconnects and the control panels.

Where is the information on the labels coming from? Was it the result of a study?

If the labels are being generated based on the table in NFPA 70E, have you verified, for each piece of equipment being labeled, that the parameters for fault current and clearing time have been met?

 

[stopsignhank]

John,

Thanks. I know it is a bit of a judgement call. I started putting labels on the panels and then disconnects. Now I see labels all over the place and could have more to go. I don't want to over label everything and then it lose it's meaning.

It just made me wonder what the definition of likely to require examination, adjustment, servicing, or maintenance while energized is.

The important thing is, I have 3 guys who would could work on electrical while it is live, and I have their buy in. They know how important it is so I don't have to go chasing them to make sure they wear their arc flash PPE.

 

[jtinge]

The following link has a good public domain document on Arc Flash Labeling Do's and Don'ts that may be helpful.

http://www.mitchellandlindsey.com/w...1/Arc-Flash-Hazard-Labeling-Dos-and-Donts.pdf

 

[stopsignhank]

Wb, Yes I am working from the tables and checking the clearing times. That does bring up a good point, since as the note on the table states, the PPE category can be reduced by one number, but not below arc flash PPE category 1, that means that I do have to label anything down stream, such as a lathe that is fed with 480 volt power.

Jt, That is a good resource. I like the reminder in there of "How would the injured guys attorney look at it"

Thanks

 

[don_resqcapt19]

...
The important thing is, I have 3 guys who would could work on electrical while it is live, and I have their buy in. They know how important it is so I don't have to go chasing them to make sure they wear their arc flash PPE.

Other than troubleshooting, in general, you are not permitted to work on electrical equipment while it is energized no matter what PPE you are using.

 

[stopsignhank]

Exactly Don,

Without their buy in their mantra would be "it will only be a second" or "I will be quick" Now their mantra is "it only takes once".