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Lockout-Tagout

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Re: Lockout-Tagout

#91

Post by tialaramex »

JoeAltmaier wrote: post #56
kozak wrote: post #55

Earlier quoted context omitted.

Can someone please point me to details of a biological mechanism that can cause someone to die hours after having seemingly survived an electric zap just fine? I never thought such things are possible.

There's a term ambulance drivers use, "Walk, talk and die". For victims of car crashes that got a hard knock to the head. A brain bleed in the brain stem (if I'm remembering it right) will build up pressure until the stem suddenly disconnects. Not electrical, but such syndromes seem to be real.

Walking Ghost phase is a phenomenon in severe exposure to radiation. The patient survives initial ill effects (probably with advanced medical treatment) and now feels fine. They have no nausea, they can walk and talk like anybody else. If you tell them they're actually dying they likely won't believe you. Inside cell reproduction has stopped, and as enough cells naturally die without replacement over the next few days their systems will cease functioning and they'll die of multiple organ failure.

Electricity definitely won't cause that, but yeah, humans can't sense all the terrible things that might have gone wrong with their bodies.

Re: Lockout-Tagout

#92

Post by trenning »

dgemm wrote: post #39
taneq wrote: post #9

After working in mining for a long while, where this kind of isolation procedure is standard and is taken very seriously (pretty much any breach of procedure is an instantly firable offense) it's terrifying coming back home and seeing people working on house wiring etc. with nothing more than a turned-off circuit breaker protecting them from electrocution or other injury. I've seen some trades start to pick up isolat…

I worked in mining as well and it's often terrifying watching the stuff that goes on all day at every urban construction site, even the things you can see from street level. Construction workers that stand directly below suspended crane loads in order to guide them down to the ground is something I see constantly and makes me nervous just to watch. If you tried anything like that at any of the mines I worked at you w…

On the crane thing, I used to work in a warehouse with 150t overhead cranes and we'd never walk under loads, but we were also the operators, they were remote controlled, so the safety was engrained from the beginning.

I also worked on sites where you don't have a conventional work space such as construction sites and it seemed to be pretty casual with being under the load if you were working in the area or holding the guide rope. In my case we didn't really have an option most times to not be in the way because it was a confined space, that's fun to think about.

I think because depending on the job crane safety and awareness are not primary concerns for a lot of construction workers and those safety practices never get taught unfortunately.

In the same factory with good crane safety, I also almost got killed by an oversight in loto when I guy through a sheet of plastic and there was 240v line running behind it, not in conduit, and I was standing on the top of a ladder. Burned through the entire razor blade in my hand. Thank fuck the blade holder was plastic.

Re: Lockout-Tagout

#93

Post by abruzzi »

habnds wrote: post #79
dgemm wrote: post #39

Earlier quoted context omitted.

I worked in mining as well and it's often terrifying watching the stuff that goes on all day at every urban construction site, even the things you can see from street level. Construction workers that stand directly below suspended crane loads in order to guide them down to the ground is something I see constantly and makes me nervous just to watch. If you tried anything like that at any of the mines I worked at you w…

My experience has been that the divide in culture tends to coincide with union/non-union workplaces.

The unusual thing though is my first exposure to "lock-out/tag-out" was as a minimum wage employee at WalMart ~30 years ago. Among other things, they had a large cardboard bailer that compress all the empty cardboard boxes into a bale about 4ft x 3ft x 3ft. It would hold it there while you threaded baling wire through and tied it off. Then it would release and dump it onto your waiting pallet jack, so you could cart it off. We had to lo/to whenever it required service.

Re: Lockout-Tagout

#94

Post by tialaramex »

NamTaf wrote: post #22
downerending wrote: post #11

Too lazy to include a link, but I believe when work is done on electrified train rails, they attach a huge bar across the power rails to short them. If they're inadvertently powered, breakers elsewhere trip. (Or, worst case, the bar melts?)

I'm not sure how this works for electrified rails (i.e. a third-rail that provides power to the engines), however for a standard rail line (i.e. just 2 tracks, with either an overhead providing electricity, or diesel engines) is used as a method of safety using the track signalling. Specifically, in many rail signalling network systems, a signal will turn red when it detects a short between the two rails in its secti…

Track circuit operating clips are used for the system you're talking about, they're just a pretty simple arrangement of giant spring clips with a deliberately short lead between them, workers are trained to apply the clips starting with the side away from the third rail, the lead is too short to make it possible to connect the third rail to the running rail if you've done it this way.

The big metal bar is different, as the poster explained it will short the (supposedly dead) power circuit in a third rail system, taking several hundred volts at quite a lot of amps until the short is detected, hence it can't just be a couple of metal clips and a cheap cable like TCOC. If some idiot re-enables power to the circuit or a fault elsewhere re-energises it despite it notionally being switched off, the bar will turn that into a full short and everybody will know there's a problem, although I'm not sure that would save anybody who happens to actually be touching the now surprisingly live rail at the time it's energised.

On overhead systems there is similarly an arrangement where a worker - after confirming that the power is supposedly dead - ensures this is true by physically grounding it. Again it's a failsafe.

Re: Lockout-Tagout

#95

Post by defterGoose »

Igelau wrote: post #29

Can we talk about how bad that lockout hasp graphic is? It looks like a drunk person broke the last crayon drawing it and just decided to have Inkscape run a trace on what they had.

I noticed that too. It's like bad, stylized clip-art. They even have an image of a real one further down the article.

Re: Lockout-Tagout

#96

Post by the-peter »

dreamcompiler wrote: post #76
JoeAltmaier wrote: post #56

Earlier quoted context omitted.

There's a term ambulance drivers use, "Walk, talk and die". For victims of car crashes that got a hard knock to the head. A brain bleed in the brain stem (if I'm remembering it right) will build up pressure until the stem suddenly disconnects. Not electrical, but such syndromes seem to be real.

It's quite real. This is why we try very hard (everything short of kidnapping) to take people to the hospital after a bad car wreck ("high energy mechanism of injury" is the term we use) even if they're walking around saying they're fine.

The EMTs didn't try very hard when I was flipped by a drunk driver. I crawled out of my window and told the EMTs I just wanted to go home and they said 'ok'.

Re: Lockout-Tagout

#97

Post by duckymcduckface »

ttsda wrote: post #71
jjeaff wrote: post #50

Earlier quoted context omitted.

110v or 240v will kill you dead where you stand. But it's not really about the voltage. The higher the voltage, the easier it is for the electricity to ground out through you. But it only takes a few milli-amps across the heart to kill you. A household line can deliver 10-20 amps. Luckily, human skin is not highly conductive and neither are rubber soled shoes. So if you are taking proper precautions and not kneeling…

It's impossible for a 240V outlet to deliver 10A through your body. Unless you're made of metal or something.

Think the point is that the voltage won't collapse under the load.

Re: Lockout-Tagout

#98

Post by grawprog »

taneq wrote: post #28
caseymarquis wrote: post #26

Earlier quoted context omitted.

After working on high voltage circuits as a lineman for a couple years, and currently writing software for industrial machinery and regularly working in industrial machining cabinets, I think that applying the same level of precaution used for mining to doing minor work on a 100V circuit is being a bit overzealous. To be fair, you're never going to get hurt by being superfluously safe, but at the same time I don't ex…

Honestly if our mains was 110V rather than "240V" (read 250-260V thanks to all of the rooftop solar in our area) I'd probably be a bit more casual about it. I've been nipped by ~100V from poor earthing and it's not that bad. 240V hurts.

I dunno, I got electrocuted repeatedly a few weeks ago, not sure the voltage, I was using a wet saw and didn't realize the rubber had worn out on my boots and the steel plate in the soles was touching the floor. Every time I turned the saw on or touched it when it was running I got electrocuted. It was kind of funny, nobody could figure out why i was the only one being electrocuted. All my coworkers came and touched it and were fine. But, it wasn't the pain that got to me, it was the weird feeling in my body after.

All the rest of that day I felt weird. My skin felt too sensitive, my arms would twitch randomly, and I just felt kind of weak and vaguely dizzy all day. I did end up figuring it out and putting a rubber mat down which immediately stopped the electrocution problem. But I really don't like being electrocuted at all. It just isn't pleasant.

On topic, all our machines get locked and tagged before opening the electrical cabinets or working on anything where you might be exposed to live wires. It's enforced by worker's comp also. We get randomly inspected fairly regularly and one thing they check is that we have lockout keys and locks on every machine breaker.

Re: Lockout-Tagout

#99

Post by drdeadringer »

RandomBacon wrote: post #12

Always verify the equipment you are working on is still physically LO-TO. I heard a story about one person who LO-TO a breaker on Friday, and Monday it had power when he went to work on it. The guy went to check the breaker, and the breaker was sitting on the ground with the lock still attached, and a new breaker in its place.

This is one of my pet peeves: you are in the middle of a test, or maintenance, or similar ... then the weekend could come, it could be a simple bathroom break and you're at a good spot to pause for five minutes.

You come back, and someone has somehow messed with your equipment. Obviously no one is using anything, everything must be available! They could have done anything from disconnect a cable to outright taking everything over for their own pet curiosity project -- all non-priority, of course. Total break of configuration to say the least, to speak nothing of potential safety issues to people or equipment.

I have had multiple people ignore multiple "test in progress", "do not touch" signs and indicators multiple times for [honestly] no good reason, LO-TO or not. If I had the authority to ban them from the area unless escorted I would have.

High priority emergency? Yes boss, I'll wait to finish or redo from scratch whatever I was doing for you. But if you're low on battery and want more Stardew Valley? You can wait or go somewhere else.

/rant

Re: Lockout-Tagout

#100

Post by anotheryou »

Simon_says wrote: post #65
anotheryou wrote: post #52

Earlier quoted context omitted.

Well if I tell my partner "do not kill me by touching anything in this box today" I trust her. It really depends on the circumstances.

That's great for you. 50% of people are below average, and they have roommates.

Yea sorry. Totally my privilege speaking here. I just found the claim "everyone should do this" a bit too broad.
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