Have you ever heard of Electrical Arc Flash? How do you read and interpret an arc flash label?
Thierry Julio Epassa- P.E. in Sixteen USA States
Electrical Engineer Director || Arc Flash, Short Circuit, Electrical Studies|| US Security Clearance || Linkedin Newsletter Author|| OSHA, IEEE, NFPA Expert||Contractor for 1328 US Federal Facilities Arc Flash Studies
Have you ever heard of Electrical Arc Flash? How do you read and interpret an arc flash label?
Figure 1 below shows an arc flash label. It is a piece of paper that must be glued in front of most electrical enclosures. It conveys critical information to follow to significantly lessen the likelihood of someone being hurt considerably during a potential arc flash incident.
If you need to see a basic intro on what an arc flash incident is, I created a 15-minute video last month that explains it in lament terms. Go to my LinkedIn newsletter, and you will see it.
There are many ways a label can look and still comply with NFPA 70E. I will take 2 popular ones.
Label 1: This is my favorite style.
How to read this label?
Since I live in the USA, I use the nonmetric system: Calories, feet, and inches. Yours may be in Joules, meters, centimeters
Step 1: Locate at least one of the following on the label
-????????? Incident energy
-????????? Arc flash PPE category
-????????? Arc rating of clothing
-????????? Site-specific level of PPE
Any NFPA 70E-compliant labels must have at least one of those data. This label has only one of those data. Incident Energy is 7.9 Cal
Step 2: Open your NFPA 70E 2021 book and read table 130.5(G).
It clearly tells you what PPE you must wear for the calorie range where 7.9 falls. Wear that PPE.
Step 3: Locate the arc flash boundary.
On this label, it states 7.2 feet. Anyone without the proper arc flash PPE must be more than 7.2 ft away from the enclosure when you open it.
Step 4: Since the label has incident energy, the standard requires us to have working distance data on the label. Locate the working distance.
It says 24 inches. No matter what you do, your chest and face must be at least 24 inches from the potential voltage source. So, for example, if you are measuring voltage while wearing your arc flash PPE, you must be at least 24 inches away from the end of your meter leads.
Step 5: In addition to arc flash assessment, your facility must have a shock assessment; make sure you follow the proper guidance for shock assessment.
It means wearing an adequate voltage glove and respecting the shock boundaries. Since this article is about arc flash, I would not discuss shock boundaries and shock assessment.
Done. You are now ready to perform your electrical tasks.
领英推荐
Summary:
Notice something? There is a ton of extra info we did not even discuss. They are NOT required to be on a label; however, they are helpful:
Another label 2:
This one looks slightly different: different colors, styles, wordings, and shapes. Yet it is a valid label; it meets or exceeds NFPA 70E labeling requirements. We will apply the same technique.
Summary:
La Fin- The End- El Fin
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1 周Be very aware of this subject matter as the same rules do not apply in the UK and in Europe as they do in the USA. Indeed, because seemingly it is assumed there is no other standard people are applying US standards in the UK. Why is that wrong people might ask. The answer is the US AF standards adopt counter measures permitting what is declared as unsafe in the UK. Don't just follow anything people write without research the standards that take precedence in the UK and Europe
DSU '23 GOLD MEDALIST Power System Engineer | Load Flow - Short Circuit | Arc Flash | Protection and coordination | on DIgSILENT power factory, ETAP, SKM, EASYPOWER. US | UK | CANADIAN | Projects.
4 周Should we add some thing like a lartest reference like NFPA 70E-2024, and according to your label latest one would be NFPA 70E 2021 You know just to add more clearance. I know their is no like a big change in PPE when we compare 2021 and 2024. But it's good to add?
Manager Health, Safety, Security & Environment, Ecomar Energy Solutions, ECOMAR Refinery, Fujairah, UAE.
1 个月It's an interesting topic, thanks for sharing. Arc flash study is to determine the incident energy available at specific device that an operator would be exposed to, while interacting with electrical equipment at facility. The result of Arc flash study will categorize the Hazard at specific equipment based on the incident energy, as well as identify the Arc flash protection boundary (the closest approach allowed before PPE must be worn). And inside the Arc flash protection boundaries a worker must be wearing proper clothing/ PPE. The PPE, main objective to wear is to restrict, or stop the burns of the body resulting from an arc flash event, to a survival level. The Arc flash Hazard study is done, in association with short circuit & protection device coordination study,as per IEEE Stnd 60909 and IEEE Stnd 242, respectively. Based on study findings, selection of PPE, electrical equipment of switchgear, substation shall be selected, rated, and warning levels A, B, shall be displayed "Arc Flash and Shock Hazard Present and Appreciate PPE are Required".
Owner - Principal Electrical Engineer at AcDc Engineering
1 个月Looks like label is associated with a transformer...which has no working while energized needs, and it's not protected with current limiting fuse.
Award-Winning OmniMedia Producer | Advocate | Visionary | JoshuaTBerglan.com | Stories That Empower
1 个月This is a fascinating topic! I hadn't realized how crucial arc flash labels are for safety. I'm looking forward to watching your video and learning more. #ElectricalSafety #Engineering #ArcFlash #NFPA70E