When it comes to arc flash and PPE, one of the more common questions that I am asked deals with gloves. These questions come bundled with a variety of scenarios, but they all seem to stem from a lack of understanding regarding the different categories we deal with during electrical maintenance. I hope to add a little clarity into your workflow today, and we’re going to do that by consulting the standard, NFPA 70E.
Now, some people might just assume that they need to layer up on heavy leathers and use bulky insulated rubbers in order to be safe and compliant in their work. Sure, more protection is usually better, but thicker gloves can lead to less dexterity when you might really need it. So, questions such as, “How much protection do I need when…?” could easily be replaced with “How many people does this task require?” to reach a smarter and safer outcome assuming all qualified personnel are using the appropriate PPE.
We’re boiling all of this down to what each type of glove will do for you, and at what categories you will be required to wear them. All of this information will help you perform your work tasks more safely. But as will all safety information, you will need to comprehend and put it into practice when it applies to your work environment.
Going forward in this article, we won’t be using the Incident Energy Analysis Method, but instead be referencing NFPA 70E Table 130.7(C)(15)(c) – Personal Protective Equipment. We will also be assuming that you have determined that there is a likelihood of occurrence of an arc flash, have taken additional safety measures required by the hierarchy of risk control methods, have determined your arc flash boundary, and are now selecting your PPE to be used inside of that boundary.
Category 1: where clothing must meet a minimum arc rating of 4 cal/cm2 (16.75 J/cm2), the required glove type is heavy-duty leather gloves.
Category 2: where clothing must meet a minimum arc rating of 8 cal/cm2 (33.5 J/cm2), the required glove type is heavy-duty leather gloves.
There are two distinctions to be made here in relation to leather gloves and heavy-duty leather gloves. When we reference heavy-duty leathers, it is to identify a glove made entirely of leather thicker than 0.07 mm that either unlined or lined with a nonflammable and non-melting material. These specifications may vary slightly depending on your use and the class of rubber glove you wear underneath. Which brings me to the next exception to leathers and their use in Categories 1 & 2: the use of rubber insulating gloves with leather protectors satisfies the arc flash protection requirement, as long as both gloves meet ASTM D120 for rubber insulating gloves and ASTM F696 for leather protectors.
Category 3: where clothing must meet a minimum arc rating of 25 cal/cm2 (104.7 J/cm2), the required glove type is Arc-rated gloves.
Category 4: where clothing must meet a minimum arc rating of 40 cal/cm2 (167.5 J/cm2), the required glove type is Arc-rated gloves.
You will notice the intentional distinction of “arc-rated” gloves as we progress into Categories 3 & 4. These special Arc-rated gloves will often have several improvements over the traditional leather-over-rubber approach. Within these gloves you will find materials such as carbon filaments and other name-brand materials and coatings that make the glove flame-resistant or self-extinguishing. These materials also lend to properties such as anti-static, cut and abrasion resistance, oil and water repellant, and heat resistance up to several hundred degrees. Additionally, Arc-rated gloves are tested under ASTM F2675 and you should always pay attention to the rating of the gloves before purchasing or using them.
If you are still uncertain about which operations or tasks carries an arc-flash risk [NFPA 70E Table 130.5(C)] or which arc-flash category certain equipment falls under [Tables 130.7(C)(15)(a) and (b)], it is in your primary objective as a qualified person to find out before beginning your work. Consult the standards, or a coworker who is familiar with them and can help. There is no excuse for putting yourself or others in danger.
Your responsibility now is to take this information and put it into practice. When you approach your work zone, especially if it has already been determined as within an arc flash boundary, you need to be thinking of protecting yourself. If your work takes any part of your body across the plane of the enclosure or you have to make contact with energized electrical conductors or circuit parts, you need to be aware of the correct PPE that satisfies your arc flash protection needs.
If you need further assistance determining the right PPE for yourself or personnel, we are happy to help.