NFPA 70E

[Bennington]

If a trough has 480V running through it [spliced or not] should it be labled catagory 0?

 

[zog]

If a trough has 480V running through it [spliced or not] should it be labled catagory 0?

Voltage has nothing to do with arc flash levels, try reading the safety FAQ's

 

[Bennington]

Thanks for your response. I did read the faq. There is a lot of good information there, however, I didn't find anything that addressed my question. The reason for my question is on a jobsite I found a trough labled catagory 0 containing 480V circuits. When I looked in NFPA70E under 600V equipment cable troughs it puts the catagory at 1, However note 3 states that with less than 10ka of short circuit current available it can be dropped by 1. I guess a better question would be other than <10ka of short circuit current is there any other reason it could be dropped to 0?

 

[zog]

Thanks for your response. I did read the faq. There is a lot of good information there, however, I didn't find anything that addressed my question. The reason for my question is on a jobsite I found a trough labled catagory 0 containing 480V circuits. When I looked in NFPA70E under 600V equipment cable troughs it puts the catagory at 1, However note 3 states that with less than 10ka of short circuit current available it can be dropped by 1. I guess a better question would be other than <10ka of short circuit current is there any other reason it could be dropped to 0?

What version of the 70E are you looking at? That "reduce by 1" note was removed 2 cycles ago if I recall, it is not in my 2012 or 2009 versions.

To answer your question, it could be 0 if they did an actual analysis and did not use the tables but in that case you should see the calculated Ei on the label as well.

 

[Bennington]

It's a laminated chart...probably 2004. Time to update. I will look for the calculated Ei on the lable. Thanks again.