Arc Flash Personal Protective Equipment

Here is the most basic answer. In the past electricians were just careful not to get a shock. Don’t get zapped! Now, you have to be careful not to get burned or blasted. That’s it…basically. But there is much more. Who started all this? OSHA says “Safety-related work practices shall be employed to prevent electrical shock or other injuries…” Well, we’re into the “other injuries.” Why? Because the number of people injured by electrical burns each year and the extent of the injuries is horrific and no longer considered tolerable.

The cal/cm2 is a measure of the ability of the fabric to withstand heat. It's a heat measurement. An "Arc Flash Analysis" is the engineering calculations performed to determine how much heat an arc may cause at a specific fault location and at a specific distance from the fault. Therefore the combination of all the clothes you are wearing must provide enough protection so that you do not get a "Second Degree Burn" or worse. The heat generated is related to the amount of fault current that can take place at a fault. The concern is "heat" from "fault current" and not voltage. Concern for voltage is concern for "shock hazard" and not "arc flash hazard." Just assuming the higher the voltage, the higher the arc flash hazard, can be a "huge mistake." In the absence of an arc flash analysis, think to yourself. "How much fault current could there be and how long would the fault last?" That last part, "how long would it last," is extremely important. Also, you must be able to justify exposing yourself to energized equipment. Wearing protective equipment doesn't make it safe to work on energized equipment.

No. There is no direct correlation between glove Class and hazard risk Category. The voltage rated gloves Classes are 00, 0, 1, 2, 3 and 4; for 500V, 1,000V, 7,500V, 17,000V, 26,500V and 36,000V. The Arc Flash Hazard Risk categories range from lower to higher and are numbered 0, 1, 2, 3 or 4. We must admit, low value numbers are used for both the gloves classes and the hazard risk categories so it's reasonable to expect some confusion without the following easy to remember statement; The body is always dressed for the Arc Flash Hazard yet the hands are only protected for shock voltage. This means that two individuals; one dressed for Hazard Risk Category 2 and the other in a Hazard Risk Category 4 Arc Flash suit could easily be wearing the same, Class 00 voltage rated gloves, while both servicing 480 volt equipment. Selection of voltage rated gloves is based on the voltage rating of the equipment. For the appropriate arc flash clothing to wear, consult the NFPA 70E tables or the arc flash label, if available.

You are not safe. You are just safer. Which is a good thing. Wearing the proper arc flash hazard personal protective equipment, PPE, does make you safer, as long as you don’t do something foolish just because you have the protective PPE on. Don’t think the chances of something going wrong are less because you are protected. The PPE does not change the probability of a blast. That false sense of security can actually increase the level of danger, making you ‘less safe.’ The arc flash hazard PPE is an effort to protect you from danger of death or serious injury. There is a lot of space between serious injury and no injury at all. An almost serious arc flash injury still hurts and can leave a scar.

Move farther back! Moving twice as far away reduces the danger by about 4. So, if you are working 18 inches away, simply stepping another 18 inches from the point of a possible blast reduces the danger by one fourth, 1/4. That is a huge reduction in danger from something as simple as moving back as much as possible. Even a little back is a lot safer. Also, ‘turn it off’ is our best advice.