What does the NEC & OSHA have to say about PPE when working on energized equipment?

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
For new project, I specify the Panduit VeriSafe Absence of Voltage Tester. This is permanently installed and lets you prove absence of voltage without removing a cover. I think once there is a couple of more devices like this are on the market the code will start to require such devices.
I did not know about this device thank you. The part number is VS-AVT-C08-L10 and it currently sells for ~$400 at a local supply house I checked, and is non stock.
probably could get a better deal if added to a job package.
the requirement is that energized work is only permitted if it's more dangerous to turn the equipment off, which applies to places like hospitals. Troubleshooting is permitted without an EEWP, as is opening up panel covers.
Good info thank you.
There is copy of 2018 70E I have access to at work, I have just never personally read it yet or had any recent training on it that I was awake for.
I made a copy of that form yesterday.
Just leads to more questions...
For the Troubleshooting that's permitted what PPE do you use for voltages over 300V in the example scenarios above?

What about DC? Say 440 -500V solar PV strings coming into a PV inverter, and the service electrician is removing the cover of the inverter to check string voltage? Probably not much AF current in the DC but still over 300V.
Thanks
 

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mayanees

Senior Member
Location
Westminster, MD
Occupation
Electrical Engineer and Master Electrician
There is copy of 2018 70E I have access to at work, I have just never personally read it yet or had any recent training on it that I was awake for.
I made a copy of that form yesterday.
Just leads to more questions...
For the Troubleshooting that's permitted what PPE do you use for voltages over 300V in the example scenarios above?

What about DC? Say 440 -500V solar PV strings coming into a PV inverter, and the service electrician is removing the cover of the inverter to check string voltage? Probably not much AF current in the DC but still over 300V.
Thanks
You should use the latest copy of 70E because it's a National Consensus Safety Standard (NCSS) and as such includes safety improvements with each edition. It's also what legal jurisdictions use, the latest edition of any NCSS. Get it with the Free Access method at NFPA.org. But, if you're just looking for the EEWP, I don't think it changed in the 2021 edition.

The EEWP will have you do Shock and Arc Flash assessments and as part of the Shock assessment you'll select rubber gloves for under your leathers from the Glove Classes that vary from ASTM Class 00 to Class 4. Class 00 works for the applications you're describing. For the Arc Flash assessment you use either the incident energy (IE) calculations or the 70E Categories method for determination of the appropriate PPE. The Categories method though is limited in what it applies to in terms of available fault current and the PPE only goes to PPE 4 which is 40 calories.

What's required for the IE calculations is the Utility contribution and ocpd, and the electrical model up to the point you're interacting with. It's typically done using power systems software for Fault, Coordination and Arc Flash calculations. I think it would be a good hustle for an electrician to partner with an engineer to do Arc Flash Studies. In my estimation, over half of the work associated with an Arc Flash Study is data collection, and all that could be done by an electrician.

And one final comment on the state of the NFPA 70E standard. I took a 16-hour virtual class recently on 70E. I found out from the trainer, who is very qualified and well-versed at the Standard, that installation of Power Quality monitoring equipment would always require an EEWP. Her contention (yes she was a lady, and fine at that) was that coming in contact with insulated cable is the same as coming in contact with uninsulated bus. This caught me by surprise because we routinely open panels and install recording CT/meters for demand information. Fortunately as it turns out the last two clients were a hospital and an NIH building so they readily signed EEWPs.
I was also paranoid about the data collection we do for Arc Flash Studies, whether she would balk at that. But for that application, the only requirement is that you be suited to cover the Incident Energy.

Good luck.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
You should use the latest copy of 70E because it's a National Consensus Safety Standard (NCSS) and as such includes safety improvements with each edition. It's also what legal jurisdictions use, the latest edition of any NCSS. Get it with the Free Access method at NFPA.org. But, if you're just looking for the EEWP, I don't think it changed in the 2021 edition.

The EEWP will have you do Shock and Arc Flash assessments and as part of the Shock assessment you'll select rubber gloves for under your leathers from the Glove Classes that vary from ASTM Class 00 to Class 4. Class 00 works for the applications you're describing. For the Arc Flash assessment you use either the incident energy (IE) calculations or the 70E Categories method for determination of the appropriate PPE. The Categories method though is limited in what it applies to in terms of available fault current and the PPE only goes to PPE 4 which is 40 calories.

What's required for the IE calculations is the Utility contribution and ocpd, and the electrical model up to the point you're interacting with. It's typically done using power systems software for Fault, Coordination and Arc Flash calculations. I think it would be a good hustle for an electrician to partner with an engineer to do Arc Flash Studies. In my estimation, over half of the work associated with an Arc Flash Study is data collection, and all that could be done by an electrician.

And one final comment on the state of the NFPA 70E standard. I took a 16-hour virtual class recently on 70E. I found out from the trainer, who is very qualified and well-versed at the Standard, that installation of Power Quality monitoring equipment would always require an EEWP. Her contention (yes she was a lady, and fine at that) was that coming in contact with insulated cable is the same as coming in contact with uninsulated bus. This caught me by surprise because we routinely open panels and install recording CT/meters for demand information. Fortunately as it turns out the last two clients were a hospital and an NIH building so they readily signed EEWPs.
I was also paranoid about the data collection we do for Arc Flash Studies, whether she would balk at that. But for that application, the only requirement is that you be suited to cover the Incident Energy.

Good luck.
Good info thanks, post a link to the 16-hour virtual class on 70E if you recommend it.
Seems like from my last hour digging thru 70E Arc-Flash PPE Category would be the only method for service electricians out on a 'service call' with limited knowledge of what they are looking at.
It appears residential service and not greater than 240V three phase = Arc-Flash PPE Category 1
The two scenarios we have been discussing are probably Category 2 but would need investigation via the form.
My PV example appears to be Category 2.
Thanks again
Cheers
 

EC Dan

Member
Location
Florida
Occupation
E&C Manager
Unfortunately the requirement is that energized work is only permitted if it's more dangerous to turn the equipment off, which applies to places like hospitals.
Troubleshooting is permitted without an EEWP, as is opening up panel covers.

There's another allowance for working on energized circuits in 110.4(B) that is fairly broad and I wonder what other people's interpretation of this part allows:

"...work on circuits that form an integral part of a continuous process that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment"

I've seen this used as justification to modify or add circuits in live 480 V control panels that run motors for industrial processes that are sensitive to shutdown.
 

jap

Senior Member
I would hope since someone's life is potentially on the line here that the facility owner, CEO, other general manager is one of the persons that signs this form and they realize what the potential losses are should something go bad vs what they think the shut down will cost.

Also gives some incentive to design so entire facility shutdown becomes less necessary or at least less often by arranging so that certain sections can be shut down without effecting other sections.

I don't care if the President signs the form.

It doesn't make working on an energized 480v breaker live any less dangerous for the person actually doing the work.

JAP>
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
There's another allowance for working on energized circuits in 110.4(B) that is fairly broad and I wonder what other people's interpretation of this part allows:

"...work on circuits that form an integral part of a continuous process that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment"

I've seen this used as justification to modify or add circuits in live 480 V control panels that run motors for industrial processes that are sensitive to shutdown.
I can't image the facility signing off on the EEWP for that reason. I know in the plants I have worked in, they would never sign off on that permit, and they shouldn't.
 

EC Dan

Member
Location
Florida
Occupation
E&C Manager
I can't image the facility signing off on the EEWP for that reason. I know in the plants I have worked in, they would never sign off on that permit, and they shouldn't.
Not defending the decision but I'll just add this was typically work done on de-energized control circuits within an energized 480 V panel.

I am genuinely curious on the wording in that part of 110.4(B). It seems to me it could be taken as an economic rationale so a plant does not have to make a potentially expensive decision to shutdown. We know it's not referring to the other perfectly legitimate reasons for energized work such as critical systems and testing since those are already covered, so what is the intended application of that wording?
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Retired Electrical Engineer - Power Systems
I am genuinely curious on the wording in that part of 110.4(B). It seems to me it could be taken as an economic rationale so a plant does not have to make a potentially expensive decision to shutdown. We know it's not referring to the other perfectly legitimate reasons for energized work such as critical systems and testing since those are already covered, so what is the intended application of that wording?
Just being a continuous industrial process, like glass making, is not sufficient.
The interruption of the process must introduce additional hazards, such as turning off ventilation to an underground mine or something that impacts the stability of a chemical plant.
 

mayanees

Senior Member
Location
Westminster, MD
Occupation
Electrical Engineer and Master Electrician
There's another allowance for working on energized circuits in 110.4(B) that is fairly broad and I wonder what other people's interpretation of this part allows:

"...work on circuits that form an integral part of a continuous process that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment"

I've seen this used as justification to modify or add circuits in live 480 V control panels that run motors for industrial processes that are sensitive to shutdown.
Note EC Dan that Informational Notes are not enforceable, so I wouldn't refer to it as an allowance, which is to say that if there was an electrical fatality associated with the EEWP that OSHA wouldn't give the employer any kind of pass. However, I think it does open the door for rationalization of doing energized work where a process could be impacted by shutting off a particular device, like an extrusion process.

To me it makes sense that if a job can be performed safely by using appropriate PPE and making an assessment that the risk is low, then it should be allowed. I think 70E goes too far with the proclamation that: "Energized work shall be permitted where the employer can demonstrate that de-energizing introduces additional hazards or increased risk.". I'd rather it say "Energized work shall be permitted where the employer can demonstrate that the work can be done safely". But that's just me. Take a case where a Data Center has a PDU with multiple 225A, 3P breakers used to power Remote Power Panels (RPPs). I think it's a simple task to wear PPE for the exposure and terminate 4/0 cables on a de-energized breaker, then turn the breaker on to power the panel. ✌️& Run
 

mayanees

Senior Member
Location
Westminster, MD
Occupation
Electrical Engineer and Master Electrician
Good info thanks, post a link to the 16-hour virtual class on 70E if you recommend it.
Seems like from my last hour digging thru 70E Arc-Flash PPE Category would be the only method for service electricians out on a 'service call' with limited knowledge of what they are looking at.
It appears residential service and not greater than 240V three phase = Arc-Flash PPE Category 1
The two scenarios we have been discussing are probably Category 2 but would need investigation via the form.
My PV example appears to be Category 2.
Thanks again
Cheers
Hey Tortuga,
The 70E class:
It's referred to as Live Virtual training. It occurs 4 hours a day over a 4-day period. There were 30 people in the class and it went pretty well. The instructor kept folks engaged/awake by using "polls" that got people to react to questions.
As far as your PPE approximations I think you're on the right track. The 240V, 3-phase PPE 1 follows the PPE Categories method for systems up to a 25kA bolted fault, table 130.7(C)(15)(a). And your DC systems PPE approximation seems to follow table 130.7(C)(15)(b). Those are the applicable Categories method tables.
✌️ (y)
 
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