And if you can't do the calculations, you can't select the correct PPE, so therefore, you are not permitted to work on energized equipment. I don't see any way that work on energized equipment can be permitted under the OHSA rules given the impossibility of selecting the correct PPE.In other words, you can't really do the calculations without making some wild assumptions.
You are technically correct. An exact calculation cannot be made due to variables. Unfortunately, there is a lot of energized work going on. So we might as well follow the guidelines and standards to achieve some level of protection vs. no protection. JMHOAnd if you can't do the calculations, you can't select the correct PPE, so therefore, you are not permitted to work on energized equipment. I don't see any way that work on energized equipment can be permitted under the OHSA rules given the impossibility of selecting the correct PPE.
This is as simple as it gets.You start with the three phase bolted fault current available at the piece of equipment (not the infinite primary maximum), convert to arc flash three phase fault current, using the time current coordination curve of the OCPD's upstream, see how long the device will take to open (clear the fault), the calculate incident energy and the associated PPE required.
Bob, the problem is that you can't determine what that number is with any certainty.You start with the three phase bolted fault current available at the piece of equipment