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 Post subject: Simplifying labels
PostPosted: Sat Jul 26, 2014 4:58 pm 
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Joined: Tue Oct 26, 2010 9:08 am
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Location: North Carolina
I've been giving some thought to making labels easier to understand. My thought is instead of using terms like restricted approach boundary, we use these:
Minimum unqualified approach distance (unescorted, with energized work ongoing)
Minimum distance at which arc flash PPE is required
Minimum distance at which shock protection methods must be used

The latter two are the arc flash and restricted approach boundaries, but the first one merges arc flash and limited approach boundaries. I'm not sure if it still has to be field determined (if one of the two hazards is not present).


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 Post subject: Re: Simplifying labels
PostPosted: Sun Jul 27, 2014 4:38 pm 
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Location: Scottsdale, Arizona
It's a great idea. I just finished an article that takes this a bit further. I don't want to give it all away yet but it is to use a larger standardized boundary for exactly as you say. Keeping unqualified people away. My view is there isn't much need for determining an AFB of 4 ft. 2 inch at one location then 3 ft. 1 inch in another etc. etc. It only affects people that don't belong there so just keep them far back. Period!
Great post Paul!


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 Post subject: Re: Simplifying labels
PostPosted: Mon Jul 28, 2014 6:46 pm 
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Location: North Carolina
You did something similar with the incident energy values years ago. This just extends the concept. I have a practical use in mind.

Right now my choices for new/replacement labels are basically that they are all "one offs". Each is unique. Either I typeset them on site (and fight with cantankerous thermal printers, changing paper rolls, etc.) or wait several days for the printer to do every one separate.

This gets even worse if you have say a mine where everything moves about every 6 months and thus the labels should be more or less continuously replaced.

So my thought is to do both. I have the following:
1. System voltage (120, 120/208, 120/240, 480, 600, 670, 2300, 4160, 7200, 13.5 kV, 22.9 kV, 230 kV).
2. Equipment type panelboard, MCC, open air, switchgear)
3. Incident energy (1.2, 4, 8, 12, 40, >40)

That is quite a list and gives me 12x6x4 = 288 combinations but only about half that are used, and I could merge say the under 300 volt group and say 480-670 to reduce the voltages to 8. Arc flash for under 300 volts will be just two cases so it cuts it down to just 2 labels. Using ArcPro above 10 kV, I can model these with just an outdoor and switchgear case, cutting them down to 6 labels. So I get 8+4x4x5 = 88 unique labels, assuming all combinations are used.

Once its done, I can preprint lots of the same thing and keep them in a cabinet in the warehouse or office. No more printing hassles.


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 Post subject: Re: Simplifying labels
PostPosted: Mon Aug 04, 2014 5:18 am 
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Joined: Tue Jul 01, 2014 8:40 am
Posts: 106
Hi All

I am all for the KISS method. I have expressed this before that under both NFPA 70E and CSA Z462 we are putting too much information on the labels. So much that it is confusing to the worker. I am all for merging of the AFB and Limited and referring it to a boundary that unqualified personnel do not cross. Yes the AFB is important information, but does it need to be on the label?? Does the electrical worker really need to know or care that at a certain provided distance they will receive a 2nd degree burn to bare skin?? Not likely. I have people up here in Canada that have been either improperly trained or received no training express that the AFB is a safe distance that one can stand and not receive a burn from the flash. Then you explain the shrapnel, hot molten metal, toxic plume, it gets more confusing to them. If we can combine and make one boundary for unqualified personnel. We are already on the road with eliminating the "Prohibited Approach Boundary" in 2015


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 Post subject: Re: Simplifying labels
PostPosted: Mon Aug 04, 2014 12:50 pm 
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You cannot say that there us no possibility of injury outside the arc flash boundary. Merely that it is an acceptable risk. The arc flash boundary is not the 1st degree burn threshold.


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