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Should you de-energize equipment before opening the doors - then re-energize to perform IR scanning?
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 Post subject: De-energize to open doors before IR scanning?
PostPosted: Sun Jun 26, 2022 9:20 am 
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Joined: Mon Sep 17, 2007 5:00 pm
Posts: 1663
Location: Scottsdale, Arizona
This question is being asked on behalf of a client to help them respond to an interpretation by their management. It is about opening enclosures for thermography.

Regarding arc flash and thermography:
Table 130.5(C) Task: Performing infrared thermography… outside the restricted approach boundary. This activity does not include opening of doors or covers.
This task is listed in the table as “No – Likelihood of occurrence” of an arc flash.

Regarding opening doors/covers:
Opening doors/covers IS a potential arc flash hazard. Many will have a qualified electrical worker that is properly protected from the arc flash open the doors followed by the thermographer conducting the IR scanning staying outside of the RAB.

Many open the doors while the equipment is energized however in this case, there is a debate about de-energizing before opening the doors and then re-energizing once the doors are open for the scanning.

For opening doors/equipment:
NFPA 70E 110.3 requires that energized electrical conductors… be put into an electrically safe work condition… This is what began the debate between the client and their management.

Here is the question:
Should you de-energize equipment before opening the doors and then re-energize to perform IR scanning?
Yes
No

Thanks for your input. I will pass it along to the client later.


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Sun Jun 26, 2022 3:06 pm 

Joined: Mon Aug 11, 2008 5:00 pm
Posts: 31
Interesting. Opening energized equipment is a possible arc flash hazard but so is operating a device i.e. interaction - closing the circuit breaker for IR scanning after the enclosure is open.


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Mon Jun 27, 2022 7:24 am 
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Joined: Tue Jan 13, 2009 5:00 pm
Posts: 585
C. Deenergize. Install thermography window. Reenergize. Take reading. Risk is reduced for subsequent scans.


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Mon Jun 27, 2022 7:28 am 

Joined: Tue Jun 14, 2022 11:35 am
Posts: 1
If we followed this logic, we would have a very difficult time collecting data for arc flash studies. Very few facilities are willing to de-energize, especially in a manufacturing environment where uptime is the rule.


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Mon Jun 27, 2022 9:11 am 

Joined: Sat May 30, 2009 6:21 pm
Posts: 21
stevenal wrote:
C. Deenergize. Install thermography window. Reenergize. Take reading. Risk is reduced for subsequent scans.


work's on switchgear , not so much on switch and MCC

i will follow, to see the legal reasoning .... but IR scanning doesn't work on a shut down plant

and this is what will happen if you start closing switch /mcc /breaker here and there ... and you will be shown the exit a couple of minute later

personnaly i still open DOORS, but not panel with no hinge


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Mon Jun 27, 2022 12:14 pm 

Joined: Mon Nov 14, 2016 7:20 am
Posts: 4
I don't necessarily agree, but I think the strict answer per NFPA 70E is that the equipment should be de-energized. Maybe you can make an argument that opening/closing a circuit breaker would introduce more hazard than opening a hinged door, but I don't know of anything other than opinion to back that up.

Personally, I think NFPA 70E should distinguish between hinged doors and opening panels that are free once you've unbolted them; a lot more risk of something going awry with the latter. That said, we were once looking at a new switchgear installed in Europe - the electrician opened a hinged door and we hear plink - plink - plink going down the switchgear interior. After our heartrates went back down, we took a second look and discovered the folks that assembled the switchgear (not a big name manufacturer) had put the door pins in upside down...


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Tue Jun 28, 2022 10:23 pm 
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Joined: Mon Jun 11, 2018 12:02 pm
Posts: 18
Location: Slave Lake, Alberta
Energizing an MCC bucket with doors open is extremely hazardous. Maybe less so if you know for sure that the load can handle the power interruption.

By design, with the door properly closed and bolted there should be containment of an explosion from a contactor blowing up or an arc flash.


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Wed Jun 29, 2022 5:40 am 

Joined: Mon Nov 14, 2016 7:20 am
Posts: 4
Just to clarify, I meant to refer to opening/closing the circuit breaker upstream of the equipment being IR'd, not the equipment itself with doors/panels wide open.

DavidChief wrote:
Energizing an MCC bucket with doors open is extremely hazardous. Maybe less so if you know for sure that the load can handle the power interruption.

By design, with the door properly closed and bolted there should be containment of an explosion from a contactor blowing up or an arc flash.


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Thu Jun 30, 2022 8:15 am 

Joined: Thu Jun 30, 2022 2:53 am
Posts: 1
I ‘d like to share the following observations:
1. There can be no question that equipment should be de-energised before opening any enclosure doors - it’s a primary safety issue. Exceptions can be made where deemed necessary, but then all appropriate regulatory safety procedures must be observed.

2. The question is in fact two questions. I find a simple NO answer misleading as it implies the 100% response is that equipment should not be de-energised before opening panel doors - which is in direct contravention of industry safety standards.
Further, the NO response to the second part of the question implies that on the basis of NO to the first part of the question, it is acceptable to perform thermal imaging inspections on energised equipment via an open panel door - again in direct contravention to industry safety standards.

4. If a thermal imaging inspection is to be carried out on energised equipment ( it’s ineffective on de-energised ), then it is best done using a thermal window, which allows partial transmission of infrared radiation from target surfaces, and with personnel in suitable level of PPE for the equipment being inspected.

5. Some food for thought - all the major OEMs now endorse and promote the advantages of installing thermal condition monitoring sensors. Digitisation is a further key driver, towards condition monitoring as opposed to periodic inspections, as the global IIOT move continues to accelerate.


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Wed Jul 13, 2022 6:49 am 
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Joined: Sun Sep 23, 2007 5:00 pm
Posts: 131
Location: Calgary, Alberta, Canada
Great topic for sure. In NFPA 70E Table 130.5(C) and CSA Z462 Table 2 unfortunately opening a hinged door and removing a bolt on cover are combined in a single work task when they should be separated.

If we have normal equipment conditions a Qualified Person can open a hinged door energized with no arc flash or shock PPE worn. This statement will surely bring back many replies and the replies already would contradict this.

An employer's Electrical Safety Program includes an electrical hazard risk assessment matrix and work task risk register table. The required risk assessment procedure is completed by an Electrical Safety Committee for the work tasks in Table 130.5(C) or Table 2. Do not accept the work task descriptions as provided, many of them need to be updated. Break out the hinged door and bolt on cover, add in Normal and Abnormal conditions for the hinged door to be evaluated. Further classify the hinged door to specific electrical equipment that would and can be opened not only for IR but for visual inspection, taking a picture for data collection, to get the other side for a voltage measure or absence of voltage measurement, to rack in or out a power circuit breaker, etc..

Junction box, MCC starter bucket, dead front SWGR door, analyzer panel, control cabinet, etc..

If the door is in an abnormal condition, then have it repaired. If you have to open a hinged door in an abnormal condition then arc flash and shock PPE would be identified at that time as appropriate risk control methods to apply.


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Wed Jul 13, 2022 7:13 am 
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Joined: Tue Jul 01, 2014 8:40 am
Posts: 109
Hi Jim, I agree from a safety perspective that de-energizing prior to opening the doors of a cabinet would be the safest thing to do pending on equipment age, condition, maintenance, etc. However, when conducting thermal imaging, do you not want the equipment to be operating at least 80%? for a more accurate reading of any hot spots? With de- energizing and then re-energizing after the doors have been opened, pending on the type of equipment, motors starting etc., would one not have to perhaps wait until all equipment, including starters, contactors... to be in full operation in order to get an accurate reading? Thanks, Len


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 Post subject: Re: De-energize to open doors before IR scanning?
PostPosted: Wed Jul 13, 2022 8:39 am 
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Joined: Tue Jan 19, 2010 2:35 pm
Posts: 158
Several things. First, I got certified to do IR in 1985, so I'm not new to this. Shutting off equipment to do an infrared scan is fine. There's no reason to leave on a machine if it's dangerous to open the doors with the power on. Clearly, heating caused by poor connections takes time, just as it takes time for those connections to cool. Metals do not cool instantly and an IR scan should only take a few minutes. With a good camera, you can see a lot and heating readily shows up. Turn off the gear, open the doors and scan. "But I can''t shut off the gear" you say. Let's suppose it's a 480 volt distribution with both breakers and fused disconnects. Why not bypass the interlocks to the switches, open the doors and scan all the gear at one time? Then, if you see unusual heating, document the problem and move on. Oh, but there are those who want the interior of this gear scanned! Sorry, there is no effective way to see all buss connections with IR if its a switchboard. You'll need to shut the board off and do a real PM. It's been my experience that IR scans can find unusual heating, but that's it. Expecting an IR scan to find everything is a mistake. IR is not a substitute for a good PM. Yes, there are IR companies who will tell you an IR combined with an ultra sound is the perfect solution. But that's just not so. Periodic shut downs and good PM's are still necessary to insure your gear is safe and reliable.
Don't misunderstand, IR is a wonderful tool, but it's not a magic bullet. Like all tools, in the hands of a qualified person, it a great option.


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