Edward
I have worked on several voltages as high as 345KV working for a Electric Utility.
for 277/480 I have exsperienced a few flashes on 480 it can be the biggest burner. you should at least wear 100% cotton and good gloves and if avalible do wear these low voltage gloves that this thread is about, and would be a good habbit to just never buy anything but cotton again for working. several years ago I was standing behind a guy in power plant scrubber (nasty damm things) working in a little 480 dissconnect and the meter touched the side of the housing and the flash melted the guy in front of me shirt and burnt his eye brows off, good thing he was wearing personal glasses (him a Journyman at time myself Apprentice)and from that day on I never wore anything but cotton at work or even at home. Now this same man about 6 years ago was burnt very bad on some 4160 and ended up looking like Freddy Krugger, just burnt very bad spent several months in a burn unit and about a year off work, and he did go back to work in the same power plant and still there today, with no ears,nose,hair on his head etc. now at time of his burn on the 4160 we had been required to wear these special shirts flame retardent etc. well guess what all that **** got burnt completly off him,I understand that his extra protection of his fruit of the looms saved his dick, but if you was to see his face and arms you would have to wonder.
Myself the biggest flash I have been in was some 25KV I accidently opened the wrong dissconect in a substation with a little over 200Amps on it, all I can say is it was the neatest thing I have ever witnessed the way the flames just ROLLED towards me like in the old cartoons with flames of death chasing the charactors, something I will never forget and as neat as it was NEVER want to exsperience that again. oh I could go on and on of flashes, some normal switching that just need to know its going to do it. Just never let anything become ROUTINE is the main thing, if you out there doing stuff sooner or later something going to happen, but yes anything above 277/480 do wear PPE Cotton will do, oh they make full switching suits to wear for anything above 4KV, but as for 120/240 voltages we just talking patty cake there, but still do wear cotton even around it.