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.
Lockout-Tagout
51–60 of 113 posts
Re: Lockout-Tagout
#52After 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.
Re: Lockout-Tagout
#53Earlier quoted context omitted.
-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...)
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…
> But it only takes a few milli-amps across the heart to kill you. A household line can deliver 10-20 amps.
10-20 amps? Not across your skin!
Usually a 220V zap at home won't cause instant death.
Re: Lockout-Tagout
#54Earlier quoted context omitted.
-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...)
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 health condition, or are just plain unlucky. But it's not the guaranteed instant death that, say a 25kV shock is.
Re: Lockout-Tagout
#55Earlier 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.
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.
Re: Lockout-Tagout
#56Earlier 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.
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.
Re: Lockout-Tagout
#57Earlier 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.
https://www.powerstudies.com/blog/what-does-severe-electrica... .
I'm guessing at the exact mechanism, but I assumed the shock knocks the heart rhythm regulators out of sequence and the body can cope for a while but eventually goes in to cardiac arrest. There is some argument about whether symptoms spontaneously show after 12 hours [www.journalagent.com/travma/pdfs/UTD_18_4_301_305.pdf - linked from said article].
Cells have a bunch of interesting electrical properties - https://en.wikipedia.org/wiki/Electrophysiology . I recall a somewhat humerous story when they discovered electricity. Galvani made a frogs leg twitch and hypothesised something like electricity in the leg. Volta said the idea was bunkum and it was caused by the different metals being used for the experiment. Volta redid the experiment without the frog and someone did Galvani's experiment without the metal so everyone got to be right.
Re: Lockout-Tagout
#58After 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, I played around enough with electronic equipment as a kid to know that coming in contact with a live 230V house wire is painful and gives you a nice adrenaline rush, but comparing it with the things that could go wrong in a mine (potentially with explosives in place) is exaggerating a bit.
Re: Lockout-Tagout
#59Earlier quoted context omitted.
-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...)
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…
I was working with a circular saw and extension cord on a ladder in light rain Monday night (gotta get that roof up before snow settles in!) and got a moderately bad hit of 110. I didn't drop dead where I stood nor was I thrown off the ladder. Don't exaggerate.
I did retire the extension cord, though.
Re: Lockout-Tagout
#60Earlier quoted context omitted.
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.)
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 to the panel, and someone turns on a big, single-phase load on a different breaker, the voltage drop on the feeder neutral could zap you. Imagine a 50A inrush current a across 1 ohm. That’s 50V for a few cycles.