My friend tested the operation of Multilin ground fault protection on a 12Kv line with ratchet cable cutters. It shut down the equipment and didn't damage the cutters - or my friend. Maybe a lot of things had to line up for that to happen. The cable had ground fault protection, the handles of the cutter were non-conductive and the cutters maintained contact with the shield as they slowly moved through the insulation toward the conductor. Or, maybe it was just luck.
My most significant scary thing wasn't high voltage, it wasn't even 120v. it was 1.5vDC but at about 150 amps. People can get very sloppy when the voltage is confused with a flashlight battery. The guy I was working with got his wedding ring across 2 bus bars on that supply. It was white hot in less than a second. We yanked him off the bus and doused it with coffee because that was what we had handy. The paramedics had to cut it off to treat the burn. He didn't lose the finger but it was never right again. I have not worn a piece of metal on my body since.
My biggest wake up call was when I got hung in the neutral on a 277 volt circuit. Was doing a renovation to an older commercial building. The building had a "crawl space" that was about 4 foot tall with dirt floor. You had to walk all the way around the building to the rear to gain access then climb your way through conduits and plumbing pipes to get to where I was going. it was a real pain in the butt. There were some new light circuits with exit / emergency lights on them stubbed into a junction box down in the crawl space. I routinely arrived to the site around 6 am and opened it up and started working. The GC and everyone else didn't get there until 7 am. I had turned on some light circuits and noticed a couple exit / emergency lights were not working. I automatically figured I crossed up the neutrals in the j - box down in the crawl space. I left the circuits on and went to crawl my way back to the j box. Sure enough I had made the splices up wrong. I thought about climbing out and walking around the building and turning off the circuit, then walking back around and climbing back through . I figured the heck with that, I can resplice this hot in less time then it would take to climb out of here.
NOt to sure exactly what I did but I do remember standing there with my arms frozen up ion that box, getting shocked. The entire time I was thinking " you are going to die if you do not get away from this" Not sure how I got away from that box but when I came to I was laying in the dirt, my heart beating like it was coming out of my chest , my arms, neck and shoulders hurt like hell and I had one hell of a headache. I don't know if I was able to jerk away and hit my head on a cast iron drain and was knocked out, or I passed out and relaxed and fell hitting my head. I never did anything like that again.
~s~ I agree with you about training the noobs. I did when I was at VoTech. Night one, a nice video from Bussmann showing what not to do, and if you did, what will happen.
Interesting, a few ‘no shows’ on nite 2. Guess I scared them off, or I may have prevented a situation. I have seen the results of a few bad faults that caused injury, and some that caused severe property damages.
One recent, ‘repair to a 1600 amp, 480 Pringle switch’ while it was hot on line side. No POCO shutdown, no permit for work, so IF they called POCO to shutdown, they would not get restoration o service without insp & approval and POCO cut in card issued.
Now, ‘service tech’ is installing some linkage for handle, linkage piece touches hot leg, and......boom. Lucky, he only had severe burns on 1 hand, arm, facial, neck and metal flakes in both eyes. The EMTs cut the nylon glove remains off his hands. His PPE gear was all in the room, still in the bag, his face shield was still in the truck.
Had another two years ago that was in the burn unit for 3 months.
looking back, I could easily have been that serv tech so many times it's downright embarrassing HotOne. In fact i didn't even know what 70E existed until i was a Jman. My EMS tenure ,witness to some nasty and a few unfortunately fatal burn victims, was really the only 'wake up' i had, other than my own electrical debaucheries.
This trade could use a few more instructors like you to put the fear of God into the noobs vs. the complacence if not downright ignorance sorts of my vintage went about with in our day
~s~ My ooops move back in the day.... Using scissor lift in whose, ballasts & bulb total replacement job. Lowered lift, drove outside to empty bulbs, boxes, etc., unto dumpster. (No recycle back then)
Raised lift to throw stuff down into dumpster. ind takes some cardboard into parking lot. I unhook lanyard, open gate & climb down the 3 steps. OOOPS, I forgot that I was raised up, did the backward swan dive to the blacktop. Split my head like a ripe melon.
Ride with EMTs to the ER, 28 stiches, and one heck of a concussion.
I haven't had any close calls involving electricity and I want to keep that way. A couple of my co-workers have gotten bit by 347V and lived to talk about it. Between the Arc Flash Safety courses and hearing first hand about the close calls others have had I've been safe enough to keep out of harms way, so far.
Close calls with metal objects is a different story.
When I was apprenticing in construction I seen a contractor from another company using a Milwaukee portable bandsaw. I asked if I could try it to shorten a piece of 3/8" threaded rod that was already screwed into the concrete ceiling. The contractor agreed and even held the bottom of the threaded metal steady while I proceeded to cut it. While I was cutting I was thinking of telling him to push on the threaded rod in a different direction - too late. Before I knew it the bandsaw blade was through and the end of the threaded rod, still being held by the contractor, came down and smacked me in the left eye...but on top of my safety glasses. I rarely wore safety glasses because it was still not being enforced at that time. There was a prior incident involving tin snips, metal framing, and a small triangle of metal framing getting stuck in my forehead, while not wearing safety glasses, that got me thinking (I didn't even realize the metal was there until I reached up to wipe the sweat off my forehead and discovered it was blood). After the incident with the threaded rod it reinforced my conviction to protect my eyes at all times. I wear them so much now that sometimes I forget I'm wearing them when I don't need to.
A malfunction at the junction -------------------------------------- Dwayne