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What tasks are reasonable when the incident energy is above 40 cal/cm2? (select all that apply)
Racking a breaker in or out
Opening doors for visual inspection
Operating a breaker/switch
Testing absence of voltage
Other - stories are encouraged!
None of the above
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 Post subject: Specific Tasks where the incident energy is greater than 40 cal/cm2
PostPosted: Sun Nov 25, 2012 2:56 pm 
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If the incident energy is above 40 cal/cm2, which of the following tasks would you consider reasonable to perform? (Select all that apply)

Assume no other options are available i.e. remote operation, opening a different upstream device etc. Also keep in mind sometimes these tasks may be necessary to create an electrically safe work condition. This is a frequently discussed paradox: Perform a potentially dangerous operation to make it safer.
  • Racking a breaker in or out
  • Opening doors for visual inspection
  • Operating a breaker/switch
  • Testing absence of voltage
  • Other - stories are encouraged!
  • None of the above

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PostPosted: Tue Nov 27, 2012 8:41 am 
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Interesting results so far, the racking one is suprising. Wonder what difference we would see for opening a hinged door vs a bolted cover for visual inspection?


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PostPosted: Tue Nov 27, 2012 10:09 am 
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Zog wrote:
Interesting results so far, the racking one is suprising. Wonder what difference we would see for opening a hinged door vs a bolted cover for visual inspection?

I didn't think of that one. I have had a bolted cover slip on more than one occasion when I pull the last bolt out with my knee shoved against it. :eek:

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PostPosted: Wed Nov 28, 2012 7:31 am 
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Or when you undo a bolt and you hear that "pachinko" sound as the interior hardware falls.


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PostPosted: Thu Nov 29, 2012 1:39 am 
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For those that left out testing absence of voltage, does this mean no work at all is performed? Ever?


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PostPosted: Thu Nov 29, 2012 7:34 am 
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jvrielink wrote:
For those that left out testing absence of voltage, does this mean no work at all is performed? Ever?

I'm not sure about others but for us we open the main which is often > 40 cal/cm2 since it is fed right off of a transformer. Then we test downstream on a device below the main which is < 40 cal/cm2. It is a bit odd because if the main is open, it could not trip and reduce the incident energy downstream but also if the upstream main device is truly open, there would not be a hazard downstream anyway.


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PostPosted: Thu Nov 29, 2012 7:36 am 
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Zog wrote:
Or when you undo a bolt and you hear that "pachinko" sound as the interior hardware falls.

Heard it a time or two in the past. Always good for causing the heart to skip a beat.


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PostPosted: Fri Nov 30, 2012 7:35 am 

Joined: Thu Nov 15, 2012 4:27 pm
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Thanks for posting this Jim, this is exactly what I was discussing with you last week.

In addition to removing bolted covers, I would also like to see installing/removing electrical recording gear and removing bolted covers from the back of switchboards (where the working distance is often much smaller than 18") added to the list. Your list, plus these three, are the most common tasks performed by our service department, and is the list of items that I've been tasked to address in our safety manual for instances above 40 cal/cm2.

I'm looking forward to following the discussion. I will certainly keep the group updated with how we revise our safety procedures to address these instances.


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