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I had to think of one thing from the last thread that would be worth a re-mention. I remembered the Dawson Mine incident. https://www.youtube.com/watch?v=yXU0jiBQfG0 "The springs on the second mechanism fell apart on removal. This was a stage-gate decision point where the work should have been stopped."
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Mar 10, 2016 02:45
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Man that's gonna cost at least several thousand dollars to fix, isn't it?
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Mar 10, 2016 02:52
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Score at the paper factory today: Paper machine: 1 Worker: -100000 This is extremely   https://www.youtube.com/watch?v=jUVmlJrMKoM I didn't see blood so he might be OK (not very likely). Three-Phase fucked around with this message at 03:51 on Mar 10, 2016 |
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Mar 10, 2016 03:49
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Platystemon posted:Do what? Attach parachutes to their æroplanes? Because it can only be done on certain small planes and it’s not magic. It won’t save you from everything and it has drawbacks like significantly cutting into passenger/cargo/fuel weight. The associated cost (destroying the plane) is a pretty big issue. Maybe with a bigger parachute and some modifications you can land without damage? Think about it, you're flying, your GPS says you're over an Arby's, and you suddenly have a major curly fries craving...
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Mar 10, 2016 04:45
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Electrode coffee cup heater (more UL than OHSA) https://www.youtube.com/watch?v=EViyccc2t9w 
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Mar 12, 2016 02:12
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Tenzarin posted:That's just a natural summoning of an elemental lord. You can dispel it by shouting this enchantment: Fifty! Pickup! Eighty-seven! Pickup! Fifty-two! Open! Fault, begone! Eighty-six! Pickup! And do not return! This is some basic but important electromancy. If your equipment is protected with an enchanted SEL relay, you should also shout "Assert! Assert!". If you have a cursed GE Multilin relay, throw it out and replace it with an enchanted SEL relay. Three-Phase fucked around with this message at 17:06 on Mar 12, 2016 |
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Mar 12, 2016 17:03
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Perestroika posted:Is it somehow really common to have access to electricity but not running hot water in China? I'm struggling to see why you'd want something like that in the first place, even if it wasn't that likely to murder you horribly. Well it is China. The warning label may only apply to male babies.
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Mar 12, 2016 17:08
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Gullous posted:Is it "Incident and Injury Free" training? I have to teach that course. Charlie talked to us at work. Third-degree burns sure are a thing. One of the lightest bits of his horrible story is after he was brought in with severe burns in came an intoxicated priest who gave him last rites. Charlie complained that the priest was going to slow, to which the priest responded "WHY DON'T YOU JUST DIE!?" causing Charlie to almost jump off his gurney in a rage. That was one of the darkest-funniest things I've ever heard. The resulting "well now I'll show him" mentality might've helped keep him alive.) Three-Phase fucked around with this message at 02:52 on Mar 13, 2016 |
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Mar 13, 2016 02:45
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Darth Freddy posted:Hour long safety meeting once a week. Work from 7am to 5pm, safety meeting at 6am. Every loving week. Oh lord. The vaguely-relevant safety meeting. I know the feeling. About the snakes - it's not as bad where I am up north, but in other parts of the US they have a really nasty habit of getting into electrical equipment. There you run the risk of a surprised snake striking a worker, or just getting electrocuted inside the gear. Like this little guy inside a medium-voltage disconnect switch: 
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Mar 13, 2016 13:50
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Gorilla Salad posted:I swear there used to be a bunch of images going around the web of some sort of junction box which was literally crammed full of snakes having a snake orgy. That's where you carefully close the box, grab your tools, and walk away quietly muttering "nope nope nope nope nope nope nope nope nope".
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Mar 13, 2016 14:04
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Sockington posted:I had to climb this 280' tower when I was an apprentice. I was loving whipped by the end of climbing and pulling up tools every few decks. I kind of wish there was some sort of netting/protection at the top to stop the possibility of any dropped items Was that a burn-off stack, isomerization unit, or something else?
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Mar 27, 2016 13:51
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Airborne Viking posted:I'll freely admit my ignorance for industrial electric stuff, but I feel like "I don't know what happened, lets throw some snow on it" is the mentality that might have caused this problem in the first place. I don't like any kind of switchgear where you need to open it up like that to be able to locally operate it. We have stuff with local operating handles for electrically controlled switchgear, you're in front of the gear but the doors are all closed when you throw the switch. (There are also little ports you can slam a broomstick into to mechanically trip the breaker in the event of a control power failure where you don't have 120VDC on the trip circuit to open the circuit breaker.)  I am thinking that was some kind of isolator switch or manual operator (I'm not familiar with Russian switchgear)? Maybe opening an isolator switch under load that's not meant to be opened under load leading to a nasty arc and a fault that isn't properly interrupted? Throwing the snow was kinda' cute. I think the damage has been pretty total at that point for that unit and probably a good chunk of the bus. Three-Phase fucked around with this message at 02:23 on Mar 30, 2016 |
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Mar 30, 2016 02:20
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Those posters are awesome. Wow. From the fire a few pages back - is a flashover and backdraft sorta' the same thing?
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Apr 2, 2016 13:57
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Airborne Viking posted:Helicopter pilots are loving crazy https://www.youtube.com/watch?v=lcjhjna9jZE Power washing lines at 500kVac. "Going inside" - flying underneath the lightning shield wires and above the conductors, is kinda' mad. 
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Apr 4, 2016 22:38
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Hot Karl Marx posted:I was taught keep them low as possible and angled up like ~15° but this is a big diesel fucker that's really hard to miss, not one of those toyotas zipping around a plant I saw one even bigger than that moving an electric motor that weighed around 30,000lbs (rotor and stator). Some of those are freaky-huge. These riggers are amazing, you can make incredibly large, heavy objects (like motors, transformers, generators) and they are the people who can move them around, sometimes using fairly simply machines and equipment too. I'm sure if you looked at their DNA going far back enough they were the guys putting together the Pyramids and Stonehenge. Three-Phase fucked around with this message at 03:15 on Apr 8, 2016 |
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Apr 8, 2016 03:12
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Sockington posted:If you get a tankless water heater, they generally cap out at 120-130*F by design. Saves you over-heating the water when you're about to cool it down with a cold-water mix. I usually do my dishes with straight hot water now since it's just at the edge of uncomfortable. I've got a tankless at work that is skin-blisteringly hot. I'm pretty sure it's more like 175F.
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Apr 17, 2016 14:32
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Sockington posted:I looked into that, and I guess it's our water heater rental company's policy not to go beyond 130*F. The problem I have is with a central heater, there's a warmup time depending on the length of the piping. (if you're in an apartment complex and take hot showers at odd hours, this can be agonizingly long, like several minutes). With those local heaters, you get water at the maximum temperature in seconds. That's not a problem as long as the maximum temperature isn't set too high. Where I'm at, on some of these you turn the faucet and it blasts burning hot water. I'm going to ask about turning the temperature setting down on them.
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Apr 17, 2016 16:02
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"Is there a carpenter on the aircraft?"
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Apr 19, 2016 23:06
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So does anyone remember that guy who showed us the ultra-dangerous coffee cup heater? Then the ultra-dangerous bath water heater? Yeah... https://www.youtube.com/watch?v=ASnLL6ebaco
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Apr 20, 2016 00:14
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Mozi posted:"You see, what happened was I swallowed a magnet by accident, and there must be some of those earth magnets out in the garden because I was washing the cucumber and it just flipped out and around and well..." "Well doctor I was just minding my own business and you see I have this high quality silicone sculpture of... well a mythological creature's anatomy, and lo and behold I slipped on the floor and..."
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Apr 24, 2016 03:56
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Drunk Driver Dad posted:I briefly considered suckling it but I've already endured my threshold of electric shocks for the year. Next time if there's some nasty screw-up that's not fixed in a reasonable period of time, you may be able to hold your rent in escrow with your local court until they fix the problem, especially if it's a serious safety issue you've documented. Check your state/municipality's applicable laws on this. (I would only do that as a last resort as it's a very provocative move. I'd only pull that if you're not planning on staying there in the long run.)
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May 3, 2016 00:29
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Slanderer posted:What the hell are you guys talking about? Is that a terminal block or a termination? Either way if I saw that, I would stop the work immediately. Sormus posted:What up, fellow paper industry slave. I picked up a little handbook on rigging at work this week. It's sort of an art.
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May 14, 2016 00:52
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Mosnar posted:Electricity travels primarily along the outside (surface) area of the wire. Said wire is now de-rated .. Some but not all. That's especially not true for DC, but it does become more applicable as you go higher and higher in frequency.
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May 14, 2016 01:02
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https://www.youtube.com/watch?v=KY3Chp-mtqQ If they synchronize the switching, it's almost like they're making music!  Barrier between personnel and energized equipment? What are you talking about?
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May 14, 2016 01:46
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DoktorVerderben posted:Saw this on the job today, the lorem ipsum part made me laugh. We need a sign like this to hang up at work. Like this: WARNING JUMPERS INSTALLED FOR TESTING/COMISSIONING PROTECTIVE CIRCUITS ARE BYPASSED JUMPERS MUST BE REMOVED BEFORE NORMAL OPERATIONS Sometimes we need to bypass circuits during testing and comissioning. Like if we're testing a piece of switchgear and there's a permissive circuit (like the status of a valve somewhere) we can fake out the status of that valve to let the switchgear operate. The problem is that's very dangerous if you leave the jumper in place. We need a big red tag like the "REMOVE BEFORE FLIGHT" ones airplanes have for stuff like pitot tube covers and whatnot. Three-Phase fucked around with this message at 02:23 on May 18, 2016 |
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May 18, 2016 02:19
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Speaking of a body ruining a batch? What about that guy who ended up inside a uranium furnace and the Ferdinand Feeds plant in Ohio? David Bocks?
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May 20, 2016 02:28
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Fun with cheapo multimeters. "If the [multimeter] fuse is rated to 250 volts, and the meter's rating says 750-volt cat... anything... then something is seriously wrong." https://www.youtube.com/watch?v=OEoazQ1zuUM&t=352s It measures 750V just fine. However if you turn it from volts to Ohms, something magical happens! (This is a big part of the difference between a $10 multimeter, and a $200/$300 name-brand industrial multimeter. And people have died due to this sort of thing. Those crappy meters are legal to sell in the US.) Three-Phase fucked around with this message at 02:26 on May 21, 2016 |
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May 21, 2016 02:22
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tater_salad posted:Becsuse as a homeowner I use a multimeter about twice a year, $200 is a lot for a tool thst gets used very little. I did a little more digging - you can get a little Extech meter for about $60, and there is a clamp-type Fluke that runs about $115 on Amazon. There are also a ton of sub-$20 meters from brands nobody has ever heard of. I would be extremely cautious using any multimeter that's under $50. As far as the $10 multimeter goes - if it said on the meter "Hey, I should only be used up to 240V and not on industrial or commercial circuits", that would arguably be much better. The problem is when it says it can safely measure up to 700+ volts, and there's a dinky fuse inside rated at 250V. Also for a home circuit, generally if there's a short circuit that you make during measurements (like measuring voltage while the probes are plugged into the ports for common and current) the short circuit current flow is a lot less than you might have than if you short an industrial or commercial power system out. mostlygray posted:Yes, 240V hurts like a motherfucker. 110 is like a kiss on the cheek from the love of your life compared to 240. I'd never mess with anything over 240. It's just not worth it unless you're getting paid. We have a lot of 120V DC systems, and the problem there is that people have volt-alert pens that don't detect DC. Depending on where you are in the world 400/240V, 480/277V, and 600/347V systems are also common for small industrial equipment that can really thump you. Highest I ever directly measured off a drive was around 700V AC, and the highest current (different equipment) was over 4000A AC on large busbars. (I had 3000A Dran-Flex probes we ran to about 130% capacity, I think the Dranetz people had a "It's possible, but not recommended" comment when I mentioned how far I pushed those flexible probes!) The 700V measurements scared me more than the 4160V systems because you took direct multimeter measurements, with the 4160V system you had potential transformers built in to step the 4160V down to 120V. Three-Phase fucked around with this message at 01:05 on May 22, 2016 |
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May 22, 2016 00:58
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mostlygray posted:For sure. That's why you always wear good boots and work with only one hand on equipment that's live. Tuck the other hand into your belt so you don't forget. That's pretty non OSHA, but it tends to work. At least you only burn your hand that way. Glad your dad's OK, but he certainly wasn't getting 100A through his body. (Assuming a really low-end 250 Ohms resistance between your dad's body and ground, you'd need 25kV to push that much current through. Plus that would be 2.5 megawatts going through your dad, so he'd probably be burned to a crisp very quickly if he did't literally blow apart.) His shock was probably in the milliamps, but small currents like that can still paralyze a person's movement/breathing or fry their heart. Lethal, but not as "spectacularly lethal" as contact with higher voltages. Frinkahedron posted:Harbor Freight gives those meters away with any purchase sometimes. If you're working on hobby electronics, car stuff, and things that generally can't kill you, I think you'll be OK. I think one of the other concerns about super-cheap meters are the quality of the probes, like if they use high-quality insulation or not. That's as important as the quality of the meter itself. Three-Phase fucked around with this message at 03:58 on May 22, 2016 |
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May 22, 2016 03:53
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LUBE UP YOUR BUTT posted:I have a uni-t multimeter advertised as 600v cat iii with a 600v 600ma fuse is this bad Depends. It's listed as CAT-III. Are you working on something like a large 480V commercial/industrial power panel or at a utility source panel? If not, you're probably fine. Can you look up the interruption rating of the fuse? That's usually measured in kiloamps and that number is really important. It's not just the fuse - how the meter is designed internally counts as well. Like if there's a 600V fuse but due to the distances in the circuit traces, the electricity could arc to another path around the fuse. Generally with a multimeter the danger is when you try and measure voltage when the probes are plugged into the current ports. That creates a short circuit the fuse has to handle. Or you overvolt the input. There was a guy at a plant who went to the wrong starter and though he was measuring 480, it was actually 2400, and his meter exploded and he died at the hospital from severe burns. There was another example at a shopping mall where an electricians meter exploded working on a 480V panel with two other people. I think the article is on Electrical Contractors Magazine. That may have been an arc triggered inside the meter due to a transient from lightning. On the Flukes I've used, the unit's display flashes and speaker beeps furiously at you like a missile lock warning if it detects probes connected between common and the current inputs but the selector is switched to volts, resistance, or any similar setting. I think the Gosen-Metrawatt have moveable windows on the selector switch so you physically cannot have probes plugged into the current ports when the unit is switched into voltage or resistance modes. That's a very foolproof design. Three-Phase fucked around with this message at 12:25 on May 22, 2016 |
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May 22, 2016 12:13
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Here's the forensic investigation on the fatal arc flash/blast at the shopping center involving the multimeter: http://m.ecmweb.com/arc-flash/case-deadly-arc-flash article posted:For reasons we will never know, after checking all three phases, he made a comment to the effect that something was not right — and returned to the center lug a second time. As he made this measurement, a fireball erupted from the panel, severely burning all three individuals and causing significant damage to the electrical equipment and surrounding area. Although witnesses and medical professionals provided rapid response and assistance, the injuries proved fatal for the electrician and the fire official.
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May 22, 2016 12:23
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How many volts are those pantograph wires?
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May 22, 2016 21:29
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I'm waiting for someone to buy a really janky electrical device off of Ebay or Amazon, they get really seriously hurt or killed, and they end up taking Ebay or Amazon to court. I'm willing to be there's probably some legalese deep in their agreements with the consumers that indemnifies them in just that kind of situation. "Hey, we're really sorry that the Lucky Dragon Superior Qualty iPhone charger electrocuted your son. Take it up with their "legal department" in China. Now piss off unless you want to upgrade to Prime." *CLICK* There have been times when I've found stuff like LED lighting on Amazon, and then I see it (and a dozen variants) are all made by some random Chinese companies that may or may not be some random person's apartment. No thanks. Three-Phase fucked around with this message at 01:45 on May 23, 2016 |
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May 23, 2016 01:43
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TTerrible posted:I want accuracy in my OSHA incident reporting in this thread. Tidbit - for medium/high voltage equipment at work, we have these metal grounding studs. Once you've shut off the power and locked/tagged the high voltage breaker, you clamp thick safety ground cables from each phase to that grounding stud. That will discharge any residual voltage and if the equipment is switched on by accident, you'll have a three phase bolted fault that should instantly trip the breaker. (My understanding is that you still need to be very careful as the ground wires could whip in a fault due to the magnetic fields and cause serious injury.) Better than being literally burned to a crisp. Also pretty much every time a circuit breaker interrupts fault current, it degrades a little depending on what it was interrupting. That could be a 20A 120V breaker in your house, or 1200A, 15kV vacuum interrupter bottles. This company had a demonstration video where after interrupting bolted faults several times the breaker (molded case, I think 240V and say 100A) would just fail to close at all and basically was broken. So causing a fault to trip a breaker should be a last resort from both a practical and safety standpoint. Three-Phase fucked around with this message at 03:11 on May 24, 2016 |
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May 24, 2016 03:07
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MG3 posted:How do you discharge a crt tvs battery? The CRT itself stores the charge, there's no battery or capacitor. You could rig up something with a small couple-watt resistor and a screwdriver hooked to ground. I don't know if they sell discharging tools or not, or if the stored charge is actually dangerous or just hurts like hell. The capacitors in some switching power supplies may also store a nasty charge, if they are competently designed there should be an internal bleed-off resistor across them but don't count on it.
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May 24, 2016 03:17
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TTerrible posted:I don't work on anything HV enough for that kind of setup For those outside the EU - RCS is like a GFCI. Better than nothing, but that seems long. The GFCI/RCI is very simple technology - a differential current transformer. You have a ring the neutral and hot wire go through. If the current is exactly he same in each, the magnetic fields cancel out and you get nothing out of the current transformer secondary. If current goes out but doesn't come back through the neutral, this generates a secondary current and the unit is signaled to trip fast. We have similar equipment for big rotating machines to detect a fault internal to the motor or generator.
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May 24, 2016 12:00
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Olewithmilk posted:I'm retarded, can someone explain this phase business to me. Do fused plugs stop all my poo poo breaking if a tree drops outside? I don't think a fuse or a breaker is a bulletproof vest - they only stop high current flow. If you suddenly get 4160V on a 120/240V circuit interesting things could happen to the loads before the fuse blows or the breaker trips. In fact if there's too much fault current the circuit breaker or fuse (more rarely) can actually fail to interrupt and blow up. A TVSS (transient voltage surge supressor) might help but I am not sure for that kind of accident (medium voltage onto a low voltage line). The other poster mentioned single-phasing. If you have a three phase motor and open one of the three power lines to it, it can still spin, but it draws a TON more current. Sometimes that can cause the other fuses to blow or the breaker to trip, but it's not good for the motor. On some of our medium voltage motor starters and drives we have power fuses about the size of your forearm with a metal spike that pops out the end if the fuse blows. They're set up so that pin slams into a fiberglass bar that hits a switch that tells the drive "Hey, a fuse blew, the motor has to stop RIGHT NOW. Stop firing the SCRS (or IGBTs) and signal the upstream breaker to trip!"
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May 26, 2016 01:35
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Not OSHA exactly but I got to try the new thermal imager at work this week so I'm very happy. These things are like magic.
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May 27, 2016 03:23
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Gorilla Salad posted:We had to put ours under lock and key because we were incapable of not playing with it constantly. They have these tiny FLIR units now that plug onto your iPhone, but the quality is really poor compared to a proper industrial/research/military thermal camera.
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May 27, 2016 12:29
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steinrokkan posted:exactly why we need the SEA PATROL Those dang scooby-doo divers. I miss that thread so much.
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Jun 1, 2016 23:23
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