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 Post subject: Energized Work Permit
PostPosted: Wed Mar 31, 2021 8:45 am 

Joined: Wed Jul 12, 2017 6:06 am
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In 70E 2021 130.2(a)(2) when a energized work permit is required. Item 2 deals with increased likelihood of injury from an exposure to an arc flash hazard. How do you interpret the increased risk of injury from exposure to an arc flash hazard?
Example, inserting or removing a bucket on a energized MCC with an IE of 5cal/cm2. Would the energized work permit be required?
Example 2, same situation but the IE is 30 cal/cm2.

What does increased likelihood mean? Does it mean if its greater than 40 cal you need energized work permit?


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 Post subject: Re: Energized Work Permit
PostPosted: Wed Mar 31, 2021 9:05 am 
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ewbengineering wrote:
In 70E 2021 130.2(a)(2) when a energized work permit is required. Item 2 deals with increased likelihood of injury from an exposure to an arc flash hazard. How do you interpret the increased risk of injury from exposure to an arc flash hazard?


It's not about an increased hazard from an arc flash. The language is explaining the justification for performing energized work. Throughout NFPA 70E the emphasis on on de-energizing - establishing an electrical safe work condition.

So this statement is defining an exception to establishing the electrically safe work condition based on shutting down creating an increased hazard - i.e. shutting down a chilled water pump on a nuclear reactor or shutting down the surgical suite in a hospital - probably a bad idea :shock:

This is a very subjective issue since one person may mentally justify shutting down for reasons x,y and z and another person may recognize it can't be shut down.

Another consideration is LEGAL.
If someone is injured or there is a fatality due to energized work, the justification used for performing energized work because someone decided there would be an increased hazard will come under great scrutiny in court. i.e. why couldn't you wait for an outage, why couldn't you do this or that.

Hope that helps to clarify 70E 2021 130.2(a)(2)!


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 Post subject: Re: Energized Work Permit
PostPosted: Wed Mar 31, 2021 11:19 am 

Joined: Wed Jul 12, 2017 6:06 am
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Jim Phillips (brainfiller) wrote:
ewbengineering wrote:
In 70E 2021 130.2(a)(2) when a energized work permit is required. Item 2 deals with increased likelihood of injury from an exposure to an arc flash hazard. How do you interpret the increased risk of injury from exposure to an arc flash hazard?


It's not about an increased hazard from an arc flash. The language is explaining the justification for performing energized work. Throughout NFPA 70E the emphasis on on de-energizing - establishing an electrical safe work condition.

So this statement is defining an exception to establishing the electrically safe work condition based on shutting down creating an increased hazard - i.e. shutting down a chilled water pump on a nuclear reactor or shutting down the surgical suite in a hospital - probably a bad idea :shock:

This is a very subjective issue since one person may mentally justify shutting down for reasons x,y and z and another person may recognize it can't be shut down.

Another consideration is LEGAL.
If someone is injured or there is a fatality due to energized work, the justification used for performing energized work because someone decided there would be an increased hazard will come under great scrutiny in court. i.e. why couldn't you wait for an outage, why couldn't you do this or that.

Hope that helps to clarify 70E 2021 130.2(a)(2)!


Jim as I understand energized work, inserting a MCC bucket into a energized MCC would not be considered energized work. Is this correct? If so, how do you address item 2 which states a energized work permit is required even if energized parts are not exposed, but there is an increased risk of an arc flash hazard? Obviously the chance of an arc flash hazard goes up when racking a bucket or breaker in or out.


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 Post subject: Re: Energized Work Permit
PostPosted: Wed Mar 31, 2021 11:35 am 

Joined: Thu Apr 18, 2019 11:42 am
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Inserting a MCC bucket onto a live bus? I would argue that is energized work...IMHO.

Mike


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 Post subject: Re: Energized Work Permit
PostPosted: Wed Mar 31, 2021 12:01 pm 

Joined: Wed Jul 12, 2017 6:06 am
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mpparent wrote:
Inserting a MCC bucket onto a live bus? I would argue that is energized work...IMHO.

Mike


Is it? You are not contacting energized parts with your hands, feet or tools as defined in 70E. I take that to mean I have to touch a energized part with a body part or a tool for it to be considered energized work.


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 Post subject: Re: Energized Work Permit
PostPosted: Thu Apr 01, 2021 6:24 am 

Joined: Thu Apr 18, 2019 11:42 am
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You say potato...I say potawto? Good debate...I think the fact that the worker is engaging a bucket on to a live bus represents an arc flash risk compared to the worker inserting the bucket on to a dead bus. Yes...I agree the worker has a low risk of shock in this case (except for the old Allis-Chalmers MCC buckets...I wouldn't want to put those in hot due to the flimsy stabs in back), but there still is an AF risk.

Mike


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 Post subject: Re: Energized Work Permit
PostPosted: Thu Apr 01, 2021 10:01 am 
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Yes, great discussion. Check out 70E Table 130.5(C). Inserting a bucket is considered a
“Yes” under the column likelihood of occurrence of an arc flash. I believe a great majority of companies have cut way back on this type of activity while energized.


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 Post subject: Re: Energized Work Permit
PostPosted: Thu Apr 01, 2021 3:54 pm 

Joined: Wed Jul 12, 2017 6:06 am
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So are we saying that everything marked yes in 130.5 (c) requires an energized work permit?

We make an energized work permit exception for troubleshooting yet there is an arc flash hazard when troubleshooting. Energized work permits are not hazardous work permits. We use JSA, JHA, job safety plans etc. for hazardous work.


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 Post subject: Re: Energized Work Permit
PostPosted: Thu Apr 01, 2021 6:25 pm 
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This discussion has gone down two paths. EEWP and Hazards.

EEWP
NFPA 70E requires an EEWP when work is performed within the RAB or interaction that may cause an increased likelihood of an arc flash.

This goes back to the 2009 Edition of NPFA 70E when the word "interaction" was added. Table 130.5(C) that I cited before was to help clarify interaction and includes tasks/equipment with a YES/NO for likelihood of occurrence of an arc flash.

The only exemptions to the EEWP listed in NFPA 70E include:
(1) Testing, troubleshooting, or voltage measuring
(2) Thermography, ultrasound, or visual inspections if the restricted approach boundary is not crossed
(3) Access to and egress from an area with energized electrical equipment if no electrical work is performed and the restricted approach boundary is not crossed
(4) General housekeeping and miscellaneous non-electrical tasks if the restricted approach boundary is not crossed

Regarding testing, is there a hazard - yes. But an EEWP is not required.

BTW, this is just a personal view and can not be construed as any formal interpretation. Someone there will need to make the final decisions.

Great discussion and glad you are performing due diligence with this subject. Thanks for doing your part with electrical safety!


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