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 Post subject: EWP & Thermography
PostPosted: Mon Nov 25, 2013 6:56 am 

Joined: Fri Apr 12, 2013 6:35 am
Posts: 8
Hello everyone,
I am asking this question in hope's I can finally put this to rest with my EHS group. I have done some searches but haven't really found a direct answer.

We perform annual thermography of all our panels and main gear. I have always had a policy of requiring an Energized work permit while doing this work, since removing the panel cover would be considered "interaction" and we would be inside the restricted approach boundary to do so.

Our EHS team is saying this is no longer required since it falls under inspection and testing and is now exempt from requiring a EWP.

What is your take on the NFPA Guidelines. your input is greatly appreciated.

Thank you.


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PostPosted: Mon Nov 25, 2013 8:10 am 

Joined: Sun Dec 12, 2010 5:00 pm
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Location: Idaho
Why would you put your employees or thermographer at risk when removing covers. They make nice viewing windows to do this with covers on. They are a bit spendy because of safety, but work well. I use Iriss IR viewing windows in the 24" length with covers and our thermographer likes them. The Energized work permit should only be used when disconnecting the power creates a greater safety hazard which this does not. Until I got all the viewing windows in, we had to rely on just checking the connections when I had a scheduled power outage and shutdown. Your EHS team is correct if you are "Outside the restricted approach boundary" which you are not when you remove the cover If you use the tables, you have to be in at least category 2 clothing when doing switchgear thermography and it is still outside the restricted approach boundary. Anything inside this boundary requires the proper PPE and an EWP. Buy the windows and don't take the risk. Everyone who signs your EWP is liable for the hazards that exist and everyone involved.


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PostPosted: Mon Nov 25, 2013 8:18 am 

Joined: Fri Apr 12, 2013 6:35 am
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We do have Windows in most of our larger gear and are working to have them isntalled in all our gear, but in our smaller sub-panels we do not. It is our company policy to perform an I.R. Scan in every panel all the way down to the disconnects. As I stated before I feel we need the EWP since we are interacting and inside the restricted boundary and the visual no - longer applies as an exemption.


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PostPosted: Mon Nov 25, 2013 9:38 am 

Joined: Wed Dec 21, 2011 5:00 pm
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What are they looking for an exemption of filling out the work permit or putting on the personal protective equipment (PPE)? If it is the latter they don't understand the "S" in EHS.
One of the reasons for doing thermography is to determine if components are hotter than they should be while in use. If one doesn't do the testing then one is likely to not catch emminant failures. Without a permit system in use one would not expect the state of the usage to remain constant. In other words the load may change significantly while doing the test which may be enough to cause a failure of one of the components and a resulting flash.

If on the other hand, the people doing the testing are authorized and well trained individuals for the task and are wearing the appropriate PPE for the distance (including arc flash protection) then there is less of an advantage of filling out a permit.


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PostPosted: Mon Nov 25, 2013 10:40 am 

Joined: Fri Apr 12, 2013 6:35 am
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I have always required EWP not only due to what is required by NFPA, but also for awareness. This is where I feel the trouble has risen, nobody wants the responsibility of signing the EWP. Unfortunately this work has to be performed to help insure the integrity of the equipment and to mitigate risk accordingly, to me calling it a visual inspection doesn't change the requirements. That's why I posted this question to everyone just to make sure I wasn't misinterpreting the requirements.


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PostPosted: Mon Nov 25, 2013 1:26 pm 

Joined: Fri Sep 21, 2012 8:23 am
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Our company has been trained in and perform thermography. One of the things I learned in the training is that temperatures can be drastically misrepresented on electrical equipment or the surface temperature that the imager reads can be greatly reduced due to the environment. This requires all thermography to be done on energized equipment for reliable images.

I will not open any equipment without PPE suited for it. I have seen too many screws cutting into the insulation of cable from the last guy in there. He was fortunate enough that the screw didn't cut into the conductor. I refuse to take the chance.

Just my opinion.


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PostPosted: Mon Nov 25, 2013 3:52 pm 

Joined: Tue Oct 01, 2013 2:56 pm
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I would definitely agree that removing covers from live high current equipment falls under the scope of energised work.

The following doesn't directly answer your question but it does speak to the issue. This is one of these cases where there are two opposing risks that have to be weighed up. Thermography is carried out to reduce risk. On the other hand, presuming a lack of immediate alternatives such as installing viewing windows, the process of removing the covers entails the risk of an accident -- PPE or none. It would be interesting to know from any other readers if there are case examples of arc fault accidents arising from thermographry activity. Accidents that happen in the course of risk reduction acitivities are particularly tragic. A question to be answered is which option carries the greater risk of injury: Removing covers to carry out cirect thermography of the conductors or not carrying out direct thermography of the conductors? The answer probably depends on the specific details of the situation.

Thermography has most value on high current circuits while live and so one can presume that the prospective arcing energy is not trivial. Removing covers from actually live busbars for example is particularly risky in my view. PPE reduces the potential consequence but it also increases the likelihood of the event due to a reduction in dexterity which in turn limits the reduction in risk provided by the PPE. PPE helps but it doesn't solve the problem. It may be that the safest option is to try to schedule in some offline inspection work where possible and at other times just scan the outside surface temperature of the equipment and take the risk of missing an incipient fault rather than exposing personnel to the arc flash risks of removing covers exposing live conductors. An undetected fault might create an arc flash hazard if it flashes over spontaneiously but the chances of someone being coincidentally close by at that random moment is tiny.


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PostPosted: Wed Nov 27, 2013 3:53 pm 
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Stick to your guns. I would have the appropriate PPE on to remove the covers. If it is a high hazard area that is of concern and it sounds like getting the correct PPE on is considered burdensome, then spend the money to re-engineer/design it to be a low HRC area.

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PostPosted: Fri Nov 29, 2013 7:00 am 
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70E requires PPE to be worn if there is a significant risk due to an electrical hazard. Two are identified (shock and arc flash). An EEWP is an administrative procedure to minimize the number of exposures, NOT an electrical job briefing. Diagnostic work does not require an EEWP, period. There is an obvious reason for this. For one, testing for voltage, current, etc., can't be done on deenergized equipment. Same is true with infrared or uv inspections. Using an EEWP for diagnostic work is reckless. If it just becomes a routine procedure then the paperwork will get pencil whipped and the purpose of the form which is to minimize energized work gets diminished. If you think you need to document an electrical job briefing aka pre task plan aka job safety analysis aka job hazard analysis, take two, etc., then by all means do so. it is widely recognized as a great way to call attention to hazards and minimizes injuries. But this is vastly different from an EEWP which is a more onerous process and should include management approval, and be executed only infrequently.


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PostPosted: Sun Dec 01, 2013 3:05 pm 
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x2 for what Paul has stated. Especially about not being routine and then people become complacent about the document.

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PostPosted: Mon Dec 02, 2013 7:16 am 

Joined: Mon Jul 08, 2013 2:33 pm
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Location: Milwaukee
I too agree with PaulEngr - The EEWP is not required but clearly the PPE is. I've been a safety guy for 30+ years and have to constantly argue with my peers that want a permit for a growing list of activities. Then they complain that the permits are poorly done.


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PostPosted: Mon Dec 02, 2013 8:36 am 
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Joined: Thu Oct 18, 2007 7:10 pm
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Location: NW USA
Removing a panel cover is not necessarily interacting with energized conductors. One must distinguish between Hazard and Risk or rote answers lead to the problems cited by Paul and Mark. NFPA 70E table 130.7(C)(15)(a) recognizes this and for example if the covers are hinged, states the hazard might be 0 with no need to PPE. (same table DOES prescribe HRC 1 for thermography performed outside the the restricted approach boundary).


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PostPosted: Mon Dec 02, 2013 9:39 am 
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Location: Swanton, Vermont
Has infrared inspection caused any arc fault accidents? Yes, some fatal, unfortunately. Instances can be found where workers were involved in an arc flash during the simplest of tasks such as closing small MCC doors.

I've been conducting infrared inspections on electrical gear for 10+ years now and have be fortunate to not have any incidents during these inspections. During this time I have complied with NFPA 70E and have kept my NFPA 70E training up to date. I've also done a number of arc flash hazard analyses.
I refer to my clients' electrical safety programs, when available, in regards to formal pre-work documentation and access to energized equipment. The different facilities are all over the board when it comes to access to energized equipment for IR inspection. Sometimes restrictions in the electrical safety program do not permit access to the equipment most critical for operations and the infrared inspection report is now less than ideal. For example, some companies do not want to access the wiring compartments of pad-mount transformers. The terminations and the transformers themselves have a history of having serious IR anomalies requiring attention. The same company has had many critical electrical distribution failures over the years at many different facilities. These failures came with sometimes lengthy shutdowns and manufacturing losses. Yet, they are still on square one when it comes to addressing this short-coming by use of inspection windows or other options.


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PostPosted: Tue Dec 03, 2013 8:20 pm 
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70E clearly states that the arc flash hazard analysis is invalid if you do not do proper maintenance. There has been plenty of research showing that some breakers will not trip at all or properly even after a couple years without maintenance, which leads to invalid arc flash calculations. Medium voltage equipment is highly susceptible to failures if it is not clean, which leads to invalidating assumptions about the probability of failures. The notes allude to this but don't spell it out. Article 200 spells out the required maintenance. I do not understand why article 130 is given greater weight than 200 when 130 itself states that it is invalid if 200 is not followed. 200 refers to NETA MTS and 70B both of which require routine IR scans or else deenergizing and doing similar invasive tests. Seems pretty clear to me that not doing the maintenance is directly equivalent to not wearing the ppe because the result is the same.


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