Arc blast PPE understanding

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just trying to get a better understanding on the ppe requirments on 120/208 , 277/480 systems. I still see alot of my co workers changing breakers on the 'hot' panel, this latest one was a 277/480 (mostly lighting panel). Other than having gloves/safety glasses cotton shirt and using insulated tools what else should be worn on these projects?? Or is this all thats needed? There was a debate on wheather the full 'arc suit' is technically required (according to NFPA 70E).

Yes ,Yes i know, one should only work hot when its 'infeasible' to turn off the power. Aparrently this was in a 'critical care area' of the hospital. So love to hear from others.
 
Well you can start here http://forums.mikeholt.com/showthread.php?t=99114

As far as the PPE required, voltage has litle to do with what PPE you need to wear, either you do the calculations or you use the tables in the 70E (Use the 2009 edition, many things changed in the tables).


Its my understanding that VOLTAGE has a LOT to do with it. for example if you are working on only 24v then none (gloves/glasses) is required. but if you step it up to 120v then it is. and the higher the voltage the (13,800 etc) then greater the protection. This is not to discount amps/short circuit calculation. Just dont want people to think that voltage doesnt play a big part in this.
 
Its my understanding that VOLTAGE has a LOT to do with it. for example if you are working on only 24v then none (gloves/glasses) is required. but if you step it up to 120v then it is. and the higher the voltage the (13,800 etc) then greater the protection. This is not to discount amps/short circuit calculation. Just dont want people to think that voltage doesnt play a big part in this.

Above 50V NFPA require both arc flash and voltage rated PPE.

Arc flash PPE is based primarily on the available short circuit current and the time it takes for the arc to be extinguished (this is incident energy). Typically higher voltages (above 1000V) have less incident energy than most people assume. I can't remember the last time I studied a 15kV system that required more than category 2 PPE.
Voltage rated PPE is, of course, entirely dependent upon the voltage.
 
the higher the voltage the (13,800 etc) then greater the protection.

Sorry, not true. You cant base anything on voltages, it is available fault current and the clearing time of the protective device. Usually 480V systems have larger arc flash hazards than 13.8kV systems.
 
When picking PPE, arc flash/blast is one of the things to look at. Voltage is another. You could protect your self from one hazard and still get killed from the other. The blast from a 12 volt battery could kill you in an arc fault situation, just as well as the voltage from a 277 volt shock with a low current flow. It is not one or the other, it is both you need to protect your self from.
 
Sorry, not true. You cant base anything on voltages, it is available fault current and the clearing time of the protective device. Usually 480V systems have larger arc flash hazards than 13.8kV systems.

For a comparison on this statement, the main power grid for California is running at less then 2 amps, I have heard it is actually less then 1 amp.
 
For a comparison on this statement, the main power grid for California is running at less then 2 amps, I have heard it is actually less then 1 amp.

That has nothing to do with this discussion, sure there is PPE for shock protection but that is not what the OP asked about. And whoever told you 1A is full of it.
 
That has nothing to do with this discussion, sure there is PPE for shock protection but that is not what the OP asked about. And whoever told you 1A is full of it.

just trying to get a better understanding on the ppe requirments on 120/208 , 277/480 systems. I still see alot of my co workers changing breakers on the 'hot' panel, this latest one was a 277/480 (mostly lighting panel). Other than having gloves/safety glasses cotton shirt and using insulated tools what else should be worn on these projects?? Or is this all thats needed? There was a debate on wheather the full 'arc suit' is technically required (according to NFPA 70E).

Yes ,Yes i know, one should only work hot when its 'infeasible' to turn off the power. Aparrently this was in a 'critical care area' of the hospital. So love to hear from others.

Actually shock protection is exactly what the OP is asking about, while they mentioned 'arc suit', their question was specifically asking about voltage specific shock protection.
 
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...The blast from a 12 volt battery could kill you in an arc fault situation....
That's one thing a lot of folks don't seem to pick up on. Our company bases arc-flash PPE exclusively on voltage. You should've seen the hard time the UPS service tech got for putting on his 40 cal. suite to work on the 48 volt batter plant; nevermind that he was looking at the business end of something like a 20kA fault current.... :rolleyes:

-John
 
Actually shock protection is exactly what the OP is asking about, while they mentioned 'arc suit', their question was specifically asking about voltage specific shock protection.

Are you trying to push my buttons? You have no idea what you are talking about, an "Arc suit" has no shock protection value whatsoever, please dont allow your misconceptions to spread to others looking for answers.
 
So i suppose that wearing the gloves would be just for shock hazard and suit would just be for flash hazard??

Yes, gloves are required for crossing the RAB for shock protection. Arc flash PPE is required for interacting with equipment insode the FPB.
 
Are you trying to push my buttons? You have no idea what you are talking about, an "Arc suit" has no shock protection value whatsoever, please dont allow your misconceptions to spread to others looking for answers.

In a word, YES :D:D:D
 
Ok, I suppose i learned something new, arc flash/blast doesnt really protect against voltage in those scenerios 277/480 120/208 So i suppose that wearing the gloves would be just for shock hazard and suit would just be for flash hazard??

My point exactly!

Zog, my point was simply that the OP was inquiring about PPE, not ARC FLASH PPE, but PPE in general, so before getting condescending and high and mighty.....get your facts straight. I realize that you know everything :rolleyes:, but the OP was confused about what he was asking, and did specifically ask about SHOCK protection in his OP, others gave him thoughts about that and you proceeded to tell everyone how wrong they were. I know that an ARC suit provides no shock protection, but the gloves and insulated tools that the OP mentioned are voltage specific shock protection and that is what my comment was about.

Now your pushing my buttons.

Read the OP before posting, and telling me what an idiot I am.

I will go calm down now.
 
My point exactly!

Zog, my point was simply that the OP was inquiring about PPE, not ARC FLASH PPE, but PPE in general, so before getting condescending and high and mighty.....get your facts straight. I realize that you know everything :rolleyes:, but the OP was confused about what he was asking, and did specifically ask about SHOCK protection in his OP, others gave him thoughts about that and you proceeded to tell everyone how wrong they were. I know that an ARC suit provides no shock protection, but the gloves and insulated tools that the OP mentioned are voltage specific shock protection and that is what my comment was about.

Now your pushing my buttons.

Read the OP before posting, and telling me what an idiot I am.

I will go calm down now.

I re-read the OP and still think the OP is asking about arc flash PPE (Like he says in the title), maybe he was confused but I dont think he is now. Relax.
 
Brothers OP is discussing working a panel that has not been placed in an "Electrically Safe Condition" Therefore the intent of the OP is in fact an arc flash/blast issue as well as a shock hazard issue. I beleive that the terminology used for these instances should be clarified. I know that when we discuss arc flash safety at work the term seems to encompass the three hazards (Shock, Flash and Blast)associated with working equipment live.


Joe
 
Should have been a hot work permit which called for PPE to be worn . It might be a critical care area and you think you can't shut down , but what if a accident happens and the panel has a major fault !
 
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