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Lockout-Tagout

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Re: Lockout-Tagout

#61

Post by aaron695 »

kozak wrote: post #55
roenxi wrote: post #37

Earlier quoted context omitted.

I've no particular experience working with electricity so maybe you just know what you are doing - but at risk of being a know-it-all on the internet that is not a very safe approach. In an industrial setting any electricity related accident is cause for a trip to the hospital no matter how minor. For starters you don't want to be casual about 110 volts [0] and for seconds the systems that control heart rhythm use el…

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.

Pretty much an urban legend.

Basically it's 'possible' to get cardiac arrhythmias that don't kill you immediately and might kill you later. But not proven, so you're better off learning about not getting zapped than this possibility. Or learning CPR.

https://link.springer.com/article/10.1007/s00392-019-01420-2

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3888927/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658458/

Re: Lockout-Tagout

#62

Post by fredley »

pjc50 wrote: post #51
symplee wrote: post #45

Any software patterns comparable to this? (Would help to have a use-case example. And how the pattern helped Vs. what was being done before)

"Lock" as in mutex? Although those don't come with a tag, which could be very handy when debugging.

Depending on the system, I think you can find out who owns the lock.

Re: Lockout-Tagout

#63

Post by zaarn »

amluto wrote: post #60
zaarn wrote: post #36

Earlier quoted context omitted.

What I learned when doing electrical work in germany, the procedure for safe electrical working is as follows: - Switch off (at circuit breaker) - Prevent switching on (lock the breaker) - Check voltage free (multimeter cleared for 230V/120V operation with long, isolated test leads) - Ground and short (put a plug into the socket connecting earth, live and neutral, you can DIY that at home safely by cutting open an un…

> Ground and short (put a plug into the socket connecting earth, live and neutral Hmm. Given that breakers in the US don’t disconnect the neutral, grounding the neutral can introduce potentially unpleasant stray currents. On the flip side, as far as I can tell, it’s entirely possible for a code-compliant installation to give you a moderate zap if you touch the neutral with the breaker off: if you have a long feeder t…

Atleast in germany the standard breakers don't either but the GFCI does and 3-phase breakers need to interrupt all phases. The neutral is also somewhat regularly grounded in the building's I've seen and atleast one grounding point is required at the distro point. Plus the breakers will trip at 50A inrush anyway.

(From experience, 50V AC won't kill you unless you are standing in a bathtub and covered yourself in conductive gel, you'll just get some minor pain in most cases)

Re: Lockout-Tagout

#64

Post by jfim »

kozak wrote: post #55
roenxi wrote: post #37

Earlier quoted context omitted.

I've no particular experience working with electricity so maybe you just know what you are doing - but at risk of being a know-it-all on the internet that is not a very safe approach. In an industrial setting any electricity related accident is cause for a trip to the hospital no matter how minor. For starters you don't want to be casual about 110 volts [0] and for seconds the systems that control heart rhythm use el…

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.

Electrical shocks can cause blood clots (deep vein thrombosis) [1] and rhabdomyolysis [2] due to muscle damage, among other things.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3096834/

[2] https://www.merckmanuals.com/home/injuries-and-poisoning/ele...

Re: Lockout-Tagout

#65

Post by Simon_says »

anotheryou wrote: post #52
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…

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.

Re: Lockout-Tagout

#66

Post by Klathmon »

lb1lf wrote: post #43
taneq wrote: post #28

Earlier quoted context omitted.

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.

-During the annual EE safety refresher course I take at work, the instructor makes a point of the fact that during domestic work, the electric shock is often merely the trigger for the real injury; you get zapped, then fall from the ladder you were on or whatever. (We have 240VAC mains, but I guess an unexpected jolt of 110VAC would be sufficient to make me jump...)

I was messing with some DIY generator wiring when I was younger and ended up getting a bite from 110.

My hand was in a shitty position kind of around a table leg, and the shock caused me to clamp down with my hand and kind of "chokehold" the table leg. It took me a lot longer than I thought it would to even register what was happening, and then to kind of throw myself away. I'd been shocked before, but this just kept going after I realized that it was happening and I just didn't know how to process it.

I ended up with some nasty burns on my hand, a really sore whole arm, and a scary realization of how it could have been a lot worse if just one or 2 things were slightly different.

Re: Lockout-Tagout

#67

Post by duckymcduckface »

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…

Tieing off if you're above 1.8m, not walking under suspended loads and de-energizing systems are so hard drilled into my brain. Haven't been on site in 4 years and I still get triggered by these.

Re: Lockout-Tagout

#68

Post by joncrane »

jfim wrote: post #64
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.

Electrical shocks can cause blood clots (deep vein thrombosis) [1] and rhabdomyolysis [2] due to muscle damage, among other things. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3096834/ [2] https://www.merckmanuals.com/home/injuries-and-poisoning/ele...

Would both of those conditions be asymptomatic between the precipitating event (electric shock) and sudden death hours later?

Re: Lockout-Tagout

#69

Post by [deleted] »

michaelt wrote: post #54
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…

> 110v or 240v will kill you dead where you stand. In my experience, when encouraging people to follow safety rules you get better results with true examples that justify the rules than with exaggeration like this. If you tell a person one thing they know isn't true, they're liable to start thinking the other things you tell them aren't true. 240v might kill you if you're up a ladder, elderly, have an undiagnosed hea…

[deleted]

Re: Lockout-Tagout

#70

Post by dsfyu404ed »

ebiester wrote: post #13
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…

How would you recommend people working on their own house implement anything more than turning off the circuit breaker? (I'm not doing anything electrical in general, but sometimes small fixes are necessary for home owners.)

>How would you recommend people working on their own house implement anything more than turning off the circuit breaker?

Tell the other inhabitants what you're doing and tape over the breaker with a note saying to see you before it's turned on.

Sure you could stick a padlock clasp on the breaker box but when your job-site has a number of people you can count on one hand a note will have 99.99999% of the same benefit and if they're trying to recklessly kill you all a lock does is buy a little time.

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