Globally there are two main methods for rating PPE and protective clothing for arc flash protection.

The first and most globally used method is a rating in cal/cm^2. This is based on test methods defined by ASTM standards and the IEC counterpart known as 61482-1-1. The cal/cm^2 rating is used throughout North American and many parts of the world. (although not all countries have moved towards arc flash studies and protection)

The selection of the appropriate arc rating is normally based on calculating the incident energy by using IEEE 1584 calculation methods.

The second method is known as the “Box Test� based on IEC 61482-1-2 that defines PPE by Arc Protection Class which includes Class 1 and Class 2. (This should not be confused with NFPA 70E PPE categories) The algorithm used for determining PPE with this method was developed in Germany and the results indicate which of the two classes are used.

Without getting into debating the merits of each method which can sometimes become quite heated, this week’s question is quite simple:

How is your PPE rated and where are you located?

cal/cm^2 / Inside North America
cal/cm^2 / Outside North America
Arc Protection Class / Outside North America
Doesn’t apply to me

Note: It’s that time of year again. The Arc Flash Forum will be taking a break during the Holiday Season. We’ll be back again after the New Year. Best wishes for a wonderful holiday season!

- Jim Phillips

Several sites I work at continue to categorize PPE as (formerly) HRC 1-4 (cal/cm2 North America), even though that is no longer sanctioned by NFPA 70E, as a method to easier categorize the needed level of protection.