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Join Date: Apr 2013
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PPE Needed When Testing

04/09/2013 2:40 PM

hello,i would like to know if there is a article in nfpa 70e about having to wear electrical gloves when testing a 24 volt i/p transmitter in a class 1 div 2 area or when testing a voltage of less than 50 volts in a class 1 div 1 area,what whould the correct PPE be for this task?

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#1

Re: PPE NEEDED WHEN TESTING

04/09/2013 2:57 PM

You have two questions here, one regarding electrical safety at extra low voltage (50V), and a second regarding testing live equipment in a hazardous area.

I don't know what the NFPA standards have to say about it in or on an (American?) site but it will probably include something about a hot work permit for working in a classed hazardous zone testing live equipment.

If the voltage being measured is not coming from an intrinsically safe protected source then it is likely a potential source of ignition regardless of how safe the voltage and energy storage potential would normally be to handle in a standard industrial environment. Gloves and other PPE won't be any help if you ignite the gas and cause an explosion.

As for the gloves, some sites have very strict requirements requiring use of gloves regardless of what the standards say, so also check the site requirements. If the standard says you don't need them but the site says yes, you need to wear them.

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#2

Re: PPE Needed When Testing

04/09/2013 4:19 PM

PPE requirements in NFPA70E are all based upon the "Incident Energy" in the equipment, measuered as calories per cm2. This is the result of the available fault current energy, the distance the person is from an arc fault, and the duration of the arc fault. The lowest threshold is 1.2 cal./cm2, the amount it takes for a 2nd degree burn, which is considered to be "healable". Generally, nobody bothers with systems that are 50V or less, unless there is a LOT of current involved.

However if you are in a classified area with the door open and you have an arc flash of any sort, that will likely be an ignition spark for the gasses in the area, so the actual energy in the electrical arc flash becomes irrelevant.

Electrical Supervisor:

"Yes, his gloves are intact so thankfully he survived the arc flash event. He was of course subsequently roasted to death in the ensuing fireball from igniting the flammable vapors, but that is not technically an electrical accident."

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#3
In reply to #2

Re: PPE Needed When Testing

04/09/2013 7:03 PM

I think that about sums it up.

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#4

Re: PPE Needed When Testing

04/09/2013 9:13 PM

First time I carried out 11KV phasing out on a feeder I was wearing a t-shirt and shorts. Last time I looked like I was due to embark on a lunar mission. If thing had gone wrong I doubt I'd have known the difference!

Your testing procedure should be done in a safe manor in line with the local safety guidelines. Including the PPE deemed required.

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#5

Re: PPE Needed When Testing

04/10/2013 3:46 AM

The PPE needed is a Hot Work Permit.

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