Hello to All,

Was hoping to get some input on some IE calcs I have for quite a few pump jack sites out here in TX. 12,470 dist to low kVA step down banks between 30-45. T style cutouts clear fault in about a cycle so I end up with IE of .07-.09 cal/ cm^2. Anyone have any thoughts on necessary PPE for this instance? Guys already have leather gloves, arc rated clothing, hearing protection, safety glasses, and hardhats; however, I'm, wondering if adding a face shield might not be a bad idea...Any thoughts? Would this be unnecessary/ over kill?

Thanks!!

I think IEEE 1584 states that results below 0.1 cal/cm2 are invalid.

Human skin is good for 1.2 cal/cm2. That's why NFPA 70E-2015 and later has a lower cutoff of 1.2 cal/cm2 for the PPE. Previous editions recommended avoiding meltable fiber clothing (and NESC still does) due to a possibility of secondary injuries from having melted synthetic fiber glued into the skin and exacerbating a burn but that's about it. Up until the point that it melts, the stuff has a pretty decent arc rating even if it's not rated.

When Paul says "Human skin is good for 1.2 cal/cm2" he means we can fully recover from a burn at that energy. It is slightly more than holding your hand over a disposable lighter

1.2 is a second degree burn.

I recommend looking at the work situation and do a risk assessment.

Some companies use arc rated, cut resistant sleeves and AR gloves and allow a cotton t-shirt.

There are a few manufacturers of the sleeves and gloves.

If there is a shock hazard, of course, rubber gloves with protectors is required.

Hugh Hoagland

You will find that the IE on the low side is much, much higher.