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 Post subject: Eletrical safety for non-electricians
PostPosted: Mon Jun 21, 2010 12:47 pm 
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Joined: Mon Jun 21, 2010 9:54 am
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Location: Plano,Texas
The NFPA 70E seems to be written to cover electricians and facilities technicians in their jobs. I had an Arc Flash Study done and with respect to 130.3 exception 1 the incident energy calculations stop at the 208Y120 panels. In our fab there are other people that work with live circuits. For the most part these people work on equipment rated at 208 or 120 volts fed from circuit breaker panels and usually with fused disconnects. Others work with electronics cord & plug connected to the wall but with step up power supplies that may produce 2000V but limited to a few milliwatts. The arc potential here is low and the proper PPE should be gloves, safety glasses, and for those working in the machines maybe long sleeves. For those working electonics I can't see the need for the long sleeves. Is there evidence the states otherwise? Is there any thought to 70E applications in CAT I and CAT II areas?


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PostPosted: Mon Jun 21, 2010 1:28 pm 
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Location: Charlotte, NC
The 70E never uses the word electrician, it has ntohing to do with the standard. It is for employee safety and applies to everyone.

You seem to have some major misconceptions, lets start with the energized work. What justifies all this energized work at your facility?


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PostPosted: Mon Jun 21, 2010 3:25 pm 
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Location: Plano,Texas
The 70E never used the word electrician but when you look at the equipment discussed in the charts and text it is mainly electricians & maintenance electricians (by license & job description) that, in my experience, does the work.

Like most facilities I require my electrically qualified individuals to power off when possible. Testing and tuning has to be done energized and testing and tuning of lithographic machines, plasma etchers and processors generally falls under the equipment technician, copier repairman and so on. Arc flash protection and even long sleeve shirts is generally overkill on these tools as they are low energy but Class 00 gloves with leather protectors and long sleeve natural fiber shirts still seem to be required. I have electrical engineers and electronics technicians that work on 2000 volt - 3 milliwatt devices. These are low enough energy that I think I should be able to let them work in short sleeves, safety glasses and have class 00 gloves around without the protectors in case they need to move their probes while energized. I'm not seeing that option in what I read in the 70E manual.

My question is do you see anything that would lead you to believe that option exists or do you have evidence/experience that might show me why that would be a bad idea?

Use of Class 00 gloves without the protectors might require additional testing. If the testing is required before each use or at such a frequent interval that an in house machine is required are they reasonably priced?


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PostPosted: Mon Jun 21, 2010 6:14 pm 
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I agree with your thinking, in fact my gut tells me the same thing. But here is the problem, since you decided not to do your arc flash study below the IEEE exception, you are bound to using the 70E tables for the catagory. So you need to use the HRC's for each task.


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PostPosted: Tue Jun 22, 2010 5:38 am 
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Joined: Wed Oct 29, 2008 6:06 am
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Location: Michigan
Article 130.7(C)(6)(a) exception

There is an exception here which says, "where it is necessary to use rubber insulating gloves without leather protectors, the requirements of ASTM F 496, Standard Specification for In-Service Care of Insulating Gloves and Sleeves, shall be met." FPN references you to 130.7(C)(9) for info on where rubber gloves are required.

However, while rubber gloves protect associates from shock hazards they do not protect them from the thermal hazard of arc flash. 130.7(C)(6)(b) requires hand and arm protection where there is possible exposure to arc flash burns. The apparel described in 130.7(C)(13)(c) -leather gloves- shall be required for protection of hands from burns.

If your arc flash hazard analysis revealed less than 1.2 cal/cm2 then I think you could apply the exception to exclude the leather protectors but without this information you are stuck using the task tables anytime you are inside the 4' AFP boundary - 130.3(A)(1).


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PostPosted: Wed Jun 23, 2010 5:01 pm 
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CPorter wrote:
I have electrical engineers and electronics technicians that work on 2000 volt - 3 milliwatt devices. These are low enough energy that I think I should be able to let them work in short sleeves, safety glasses and have class 00 gloves around without the protectors in case they need to move their probes while energized. I'm not seeing that option in what I read in the 70E manual.


3 milliwatts ... Isn't that ~3 total calories per HOUR? Unless I'm missing something burn injuries are out of the question.

70E cannot reasonably be applied to every situation and 3mW devices are out of scope. Protecting against shock but not heat seems reasonable.


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PostPosted: Mon Aug 23, 2010 5:21 am 
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FR PPE uniforms for Operators

I am trying to understand what tasks require Fire Retardent (FR) PPE for Arc Flash. Our operators at times have to change power sources; close disconnects; Start/Stop etc. but Operators do not enter electricial panels only our electricians. So my question is, do all our plant personnel need FR uniforms operators included?


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PostPosted: Mon Aug 23, 2010 7:35 am 
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1) OSHA requires employers to protect against hazards.
2) NFPA 70E says that an arc flash hazard exists provided a person is "interacting" with equipment in a manner that could cause an electric arc.

Given those two facts I would say that your operators should be in FR clothing if the incident energy behind the cover is greater than 1.2 cal/cm2, unless you use and document a hazard/risk approach to PPE as part of your safety program. In that case use PPE appropriate for the hazard/risk category of the task and equipment in question.

That's my opinion of course, others may have a different spin.


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PostPosted: Tue Aug 24, 2010 6:25 am 
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Location: Bowling Green, KY
[font="Comic Sans MS"][SIZE="3"]My employer does not require FR rated clothing for production people, just welders and electricians. To make someone who is just hitting a PB on a control panel wear FR clothing seems a bit much since the operator will not be getting anywhere near any of the arc flash boundaries. We do teach boundaries to everyone in the shop though as part of our training requirements.[/size][/font]


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PostPosted: Wed Jun 01, 2011 9:09 am 
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arcflash71 wrote:
1) OSHA requires employers to protect against hazards.
2) NFPA 70E says that an arc flash hazard exists provided a person is "interacting" with equipment in a manner that could cause an electric arc.

Given those two facts I would say that your operators should be in FR clothing if the incident energy behind the cover is greater than 1.2 cal/cm2, unless you use and document a hazard/risk approach to PPE as part of your safety program. In that case use PPE appropriate for the hazard/risk category of the task and equipment in question.

That's my opinion of course, others may have a different spin.


I will respectfully disagree with this assessment. personnel that are simply standing outside of the panel itself, should not require the wearing of PPE, since they are not directly exposed to the gear. they are not interacting, only standing by it while all bus material is not exposed. that would mean if I'm walking by a piece of swgr or MCC in an electrical room, I would have to wear PPE. No, I don't believe that that is the intention of the code.


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PostPosted: Wed Jun 01, 2011 9:41 am 
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"Interacting" with live gear doesn't mean simply standing in front of a panel, so we agree.


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