# 40 cal suit



## Big John (May 23, 2010)

Gloving or sticking?


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## Bbsound (Dec 16, 2011)

Big John said:


> Gloving or sticking?


^^^^^^^^^^^^^ what he said. 

Every inch clearance makes a difference


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## nolabama (Oct 3, 2007)

Gloving


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## uconduit (Jun 6, 2012)

Don't they make 40cal/cm balaclavas? I have a 44 hardhat liner and they make all-nomex jackets too with at least that high a rating, I mean do you really have to look like you're refueling the DeLorean while working on overhead lines?

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edit

i found one, now you'll just look like the burglars from a Christmas Story....

http://www.frsafety.com/product/458_calcm_Arc_Goggle_Balaclava


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## Zog (Apr 15, 2009)

nolabama said:


> So it's safety cert time and it comes to our attention that we are supposed to wear a 40 cal suit for overhead primary work. Is this stupid? If not why not. If so why.


Do you fall under NFPA 70E or NESC rules?


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## sbrn33 (Mar 15, 2007)

nolabama said:


> So it's safety cert time and it comes to our attention that we are supposed to wear a 40 cal suit for overhead primary work. Is this stupid? If not why not. If so why.


You work on overhead primary? What voltage.


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## nolabama (Oct 3, 2007)

Zog said:


> Do you fall under NFPA 70E or NESC rules?


Nfpa 70 e


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## nolabama (Oct 3, 2007)

sbrn33 said:


> you work on overhead primary? What voltage.


7200-30000. Rule is for over 800vac. Company rule.


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## Zog (Apr 15, 2009)

nolabama said:


> Nfpa 70 e


70E is weak for overhead lines, you should look at the new NESC requirements for arc flash protection.


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## nolabama (Oct 3, 2007)

Zog said:


> 70E is weak for overhead lines, you should look at the new NESC requirements for arc flash protection.


Is 40 cal required?


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## Zog (Apr 15, 2009)

nolabama said:


> Is 40 cal required?


Depends if an arc flash analysis is done, what the working distance is, or what the specific task is. More complex than you think so most companies fail safe on procedures and require the flash suit, and that is probably best.


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## JohnR (Apr 12, 2010)

I have a nephew who works for Asplund and he says that 98% of the time the calc comes back as 15 cal would cover the potential blast. The upstream fuse has to do with the calc besides the voltage. 

I kind of have a hard time believing that 15 is enough for that, but its not my calc either


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## varmit (Apr 19, 2009)

USUALLY the arc flash potential is less than you would think on medium voltage equipment due to the lower current level. The shock hazard is of course much higher due to the voltage, but an arc flash suit is not much use for medium voltage insulation. 

I would really hate to wear a 40 cal suit outside in the sun, in the summer, for a long time period. Heat stroke would be more of an issue.


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## Big John (May 23, 2010)

JohnR said:


> I have a nephew who works for Asplund and he says that 98% of the time the calc comes back as 15 cal would cover the potential blast. The upstream fuse has to do with the calc besides the voltage.
> 
> I kind of have a hard time believing that 15 is enough for that, but its not my calc either


 Not unheard of. Lower currents with faster protection than most 480V distribution systems often makes the incident energy much lower. 15cal might be right for a lot smaller distribution spurs.

As an example: The plants I used to work in, some of the most hazardous equipment weren't the 13.8kV 20MW generators, but instead the 225A 480V panelboards feeding the office heaters. The differential protection on the generators was so good it kept them in the HRC2 range, bu the 480V panels were HRC4.


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