Arc Flash Suits for Disconnects?

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jmellc

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Location
Durham, NC
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Facility Maintenance Tech. Licensed Electrician
A friend tells me the place he works is starting a new arc flash rule. AF protection must be worn when turning a disconnect off or on. I could not believe it. Has anyone else heard of this?
 
Yes sir

Yes sir

Yes, that's NFPA 70E.
You wear PPE suited to the incident energy level at the switch.
More specifically, you wear PPE in accordance with the Electrical Safety Program the company has in place. They may make determination that operation of safety switch is an acceptable risk (low enough) to not warrant PPE. But generally speaking, you need to assess the incident energy level at the bus with an arc flash study, then adhere to the requirements of the label. (or use 70E tables 130.7(C)(15)(a))
Smaller motors are generally under 8 calories, so the PPE requirements are not overbearing. But 40 calories is the limit of PPE 4, the "arc flash suit" and it becomes difficult to work in. Anything above 40 calories and you have to remotely operate it.
 
mayanees said:
..., then adhere to the requirements of the label. ....
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NFPA70E requires you to assess the risk (e.g. the chance that a fault will occur), then you provide the appropriate PPE based on the label information.

Many companies find it more expedient to just always require the use of the maximum PPE, rather than leave risk assessment in the hands of individuals. Other companies have developed their own 'risk versus task' policies (the hazard is the calculated incident energy).
 
In some cases a "disconnect switch" can be a simple toggle switch like what is commonly used for lighting switches.

Guess the office staff will now be suiting up when they turn the office lights on each morning:cool:
 
The Department of Navy bought us 8 cal pants and shirts and we are required to wear them when reporting to work. To turn a breaker on we are also required: hardhat, safety glasses, and rubber gloves for up to 300 VAC. Has anyone seen a 120 volt single pole circuit breaker fail so catastrophically as to warrant that kind of protection?


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Sparky3141 said:
The Department of Navy bought us 8 cal pants and shirts and we are required to wear them when reporting to work. To turn a breaker on we are also required: hardhat, safety glasses, and rubber gloves for up to 300 VAC. Has anyone seen a 120 volt single pole circuit breaker fail so catastrophically as to warrant that kind of protection?


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Next question if they have seen it is whether or not it was applied correctly. 10 kAIC breaker in a situation where 40 kA is available is asking for something like that to potentially happen.
 
I read a bit and saw that OSHA requested NFPA to come up with these guidelines.

For what reason? Did a disconnect switch somewhere explode? I don't say it has never happened but I started electrical work in 1976 and have never seen or heard of a problem turning a disconnect off and on.
 
jmellc said:
For what reason? Did a disconnect switch somewhere explode? I don't say it has never happened but I started electrical work in 1976 and have never seen or heard of a problem turning a disconnect off and on.
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Surly at some point, somewhere a disconnect has injured the operator. Like wired I feel in these cases the equipment was likely be used beyond its ratings.
 
iwire said:
Surly at some point, somewhere a disconnect has injured the operator. Like wired I feel in these cases the equipment was likely be used beyond its ratings.
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Or it fell of the wall and hit the worker on the head. That's why the hardhat is required. ;)



SceneryDriver
 
Seems that OSHA Kool-Ade has gotten stronger as common sense has gotten weaker. Down the road, we will all have to wear flame retardent suits to drive cars since we are travelling with 20 or so gallons of gasoline. Light a campfire, where is your suit? Light a fireplace, need that suit. Don't forget birthday cake candles, church candles, oil lamps, etc. Think of the heat from electric or gas ovens & the further risk of explosion from gas. Then we need suits that are explosion proof as well. Safety is a serious business we have too long neglected in too many areas.
 
jmellc said:
Seems that OSHA Kool-Ade has gotten stronger as common sense has gotten weaker. Down the road, we will all have to wear flame retardent suits to drive cars since we are travelling with 20 or so gallons of gasoline. Light a campfire, where is your suit? Light a fireplace, need that suit. Don't forget birthday cake candles, church candles, oil lamps, etc. Think of the heat from electric or gas ovens & the further risk of explosion from gas.
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If you do any of the above for pay, as an employee, there are likely already OSHA rules that apply.
 
And those of us that participate on this site are just from one general trade area, and a few overlapping trades.

Those OSHA rules apply to all employees no matter what their job is.

It has gotten to the point you don't do any task you were not specifically trained to do no matter how simple the task may appear to be.
 
kwired said:
And those of us that participate on this site are just from one general trade area, and a few overlapping trades.

Those OSHA rules apply to all employees no matter what their job is.

It has gotten to the point you don't do any task you were not specifically trained to do no matter how simple the task may appear to be.
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I am called occasionally to do electrical work for my former employer where I retired in 2000. 20 years ago it was common for an employee to change florescent ballasts or any other job he or she could do. Now employees are forbidden to do any task they except what they were hired/trained to do. Ballast change or any electrical work must be done by licensed electrician.

Means more money for me but shows how far we have come.
 
electricman2 said:
I am called occasionally to do electrical work for my former employer where I retired in 2000. 20 years ago it was common for an employee to change florescent ballasts or any other job he or she could do. Now employees are forbidden to do any task they except what they were hired/trained to do. Ballast change or any electrical work must be done by licensed electrician.

Means more money for me but shows how far we have come.
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Electricians doing electrical work is not so much anything oversimplified, but even an electrician may not be allowed to use a certain tool or equipment if he has not been trained how to use it. Changing ballasts - you can't climb a ladder, use a lift or scaffold to get to your work if you were not trained how to properly use those items.
 
So why wouldn't a disconnect switch require PPE to operate? My question simply because some of the videos I've seen, show a disconnect switch exploding.

Out here where my high AIC might be 30,000 at the utility side and 10-22K on customer side, might not be a huge deal, but I've heard of places like Long Island having up to 100,000 AIC so at a disconnect it may still be in the 65-48K range.

One company I deal with out here wears them just to remove the dead front from a residential panel.
 
cowboyjwc said:
So why wouldn't a disconnect switch require PPE to operate? My question simply because some of the videos I've seen, show a disconnect switch exploding.

Out here where my high AIC might be 30,000 at the utility side and 10-22K on customer side, might not be a huge deal, but I've heard of places like Long Island having up to 100,000 AIC so at a disconnect it may still be in the 65-48K range.

One company I deal with out here wears them just to remove the dead front from a residential panel.
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This is one thing that has always puzzled me. Years ago we had a lot of equipment with exposed energized parts, open knife switches, etc. It makes sense to enclose all those hazards. I realize many of those installations maybe didn't have the available fault current we have in many instances today, but with all the testing, marking, and application information for AIC ratings there is, why on earth isn't a switch able to safely contain the arc flash that could be developed if the switch is applied within it's rating? There are non electrical professionals that operate some of this equipment - how can we expect them to know the dangers. Many of them assume turning power off to something is generally making electrical hazards "safer" but the very act of turning something off can be pretty dangerous in itself:(.

If it is going to blow up in your face when you operate it, we may as well go back to open switches - at least people will be a little more cautious around the equipment then. We do have open switches for medium and high voltage gear, but also design those so that you have some distance from operating devices, or need training and special equipment for direct operation of them.
 
Wearing PPE isn't about operating things under normal conditions, it's about the abnormal conditions.

In all the years you've been doing this, how many breakers have you had blow up in your face? My guess would be the same number as me, none. But how many do you need to blow up in your face before wearing PPE is a good idea?

Where's Zog when we need him?
 
electricman2 said:
I am called occasionally to do electrical work for my former employer where I retired in 2000. 20 years ago it was common for an employee to change florescent ballasts or any other job he or she could do. Now employees are forbidden to do any task they except what they were hired/trained to do. Ballast change or any electrical work must be done by licensed electrician.

Means more money for me but shows how far we have come.
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My son has about 5 weeks of experience and a journeyman got ran off of the job because he wanted him to change a ballast hot. He refused and job foreman told journeyman he was not to tell him to do that again. Journeyman's reply was it's only 120 volts!!!
Apparently OSHA is a small town in Texas to him........
 
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cowboyjwc said:
So why wouldn't a disconnect switch require PPE to operate? My question simply because some of the videos I've seen, show a disconnect switch exploding.

Out here where my high AIC might be 30,000 at the utility side and 10-22K on customer side, might not be a huge deal, but I've heard of places like Long Island having up to 100,000 AIC so at a disconnect it may still be in the 65-48K range.

One company I deal with out here wears them just to remove the dead front from a residential panel.
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Were those videos documenting actual cases or just staging a "what if"?
 
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