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They won't glow super bright - that's a fairly long exposure that I found here - but they will definitely light up. I used to live in an apartment that was nearly directly under some ~500kv lines (the poles were in the parking lot about 100 ft from my front door) - when I switched to CFLs all of my lights would (barely) glow all the time. It was kinda neat to hang out on the porch on a humid night with a beer and and listen to the lines crackling/see a bit of corona discharge around the insulators. I haven't turned into a super human or been raped by cancer.. yet. I will admit I was always a little concerned that someone would nail one of the poles in the parking lot and cause some ugly stuff, despite the substantial concrete bases. I also always wondered how the gently caress code permitted any of that, though the place was built in the late 60s..
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# ? Nov 14, 2012 10:00 |
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# ? May 13, 2024 04:55 |
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The Cleaner posted:Holy.. crap. http://www.cancer.gov/cancertopics/factsheet/Risk/magnetic-fields
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# ? Nov 14, 2012 11:41 |
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Power lines do not cause cancer. Cell phone towers do not cause cancer. Wifi does not cause cancer. Same goes with headaches, nausea, Alzheimers, etc etc. Electrosensitivity is complete pseudoscience and anybody who is trying to convince you that your electricity is invisibly harming you is trying to sell you something.
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# ? Nov 14, 2012 13:21 |
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edit: carry on.
Simulated fucked around with this message at 00:21 on Nov 15, 2012 |
# ? Nov 14, 2012 17:54 |
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The stress response to low socioeconomic status associated with neighbourhoods with lots of overhead power lines is associated with cancer. But tackling that that would involve problems that can't be solved by NIMBYism.
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# ? Nov 14, 2012 17:56 |
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There was a guy a while back that did a big art thing laying out 1300 flourescent light bulbs under a high power line: "Field" by Richard Box http://vimeo.com/11137816
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# ? Nov 14, 2012 19:27 |
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peepsalot posted:There was a guy a while back that did a big art thing laying out 1300 flourescent light bulbs under a high power line: The thing you have to remember with photographs is by adjusting the exposure you can make objects like that glow as brightly or dimly as you want them to. some texas redneck posted:They won't glow super bright - that's a fairly long exposure that I found here - but they will definitely light up. E;F,B Three-Phase fucked around with this message at 23:01 on Nov 14, 2012 |
# ? Nov 14, 2012 22:58 |
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Ender.uNF posted:For the magnetic field part, we are living in a constant magnetic field given off by the earth. grover fucked around with this message at 23:21 on Nov 14, 2012 |
# ? Nov 14, 2012 23:19 |
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ABB's game-changing HVDC breaker. Just a stack of IGBTs and a mechanical breaker combined?
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# ? Nov 17, 2012 15:29 |
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grover posted:That's great and all, but has nothing to do with what's lighting up fluorescent bulbs under power lines, which is caused by the electric field, not an electromagnetic wave. For example, 200kV lines 20 meters overhead will create an electric field strength of appx 100v/cm. This is well under the 33kV/cm dielectric breakdown strength of dry air so it doesn't arc, but because it's at 60Hz, it does create a strong capacitive effect that can induce current to flow through conductors. It's such a small amount of current that it's not normally noticeable, but even small amounts of current can make fluorescent bulbs glow. This is such a minor point, but I'm bringing it up because you insisted on telling him that he was totally wrong. Electricity in a transmission line is totally an electromagnetic wave. You are right in that he is putting on airs a little bit by talking about waves and especially photons when a fluorescent light bulb is so small compared to the wavelength at 60 Hz, but he isn't wrong. silence_kit fucked around with this message at 23:40 on Nov 17, 2012 |
# ? Nov 17, 2012 16:26 |
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Three-Phase posted:ABB's game-changing HVDC breaker. This is going to be big for all those theoretical wind farms in the middle of nowhere or offshore.
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# ? Nov 18, 2012 23:32 |
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Cheesemaster200 posted:This is going to be big for all those theoretical wind farms in the middle of nowhere or offshore. Hush! Imagine the benefits of adding an extra 500 megawatts to the grid! Not that much compared to other power plants.
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# ? Nov 19, 2012 00:21 |
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Three-Phase posted:Hush! Imagine the benefits of adding an extra 500 megawatts to the grid! At least it's operating at 17% efficiency! Speaking of which: a 500 MW wind farm in the German North Sea has just been cancelled/postponed because the utility can't get its poo poo together with the HVDC converter stations. The idea was to build a big AC/DC platform, connect various wind farms at 150 kV (AC) and then send it to shore at DC. Too bad really, I had a year and half of contract work lined up for that bad boy and now I'm scrambling to get some work after March next year.
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# ? Nov 19, 2012 22:53 |
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some texas redneck posted:I used to live in an apartment that was nearly directly under some ~500kv lines (the poles were in the parking lot about 100 ft from my front door) - when I switched to CFLs all of my lights would (barely) glow all the time. It was kinda neat to hang out on the porch on a humid night with a beer and and listen to the lines crackling/see a bit of corona discharge around the insulators. I have never actually seen corona discharge, but I've heard it walking underneath 345kV lines.
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# ? Dec 14, 2012 01:36 |
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What are the giant spherical objects on the lines on poles? Would it there be a reason why they would keep them on the line for over two years?
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# ? Dec 14, 2012 17:27 |
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SlayVus posted:What are the giant spherical objects on the lines on poles? Would it there be a reason why they would keep them on the line for over two years?
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# ? Dec 14, 2012 17:30 |
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That's what happens when kids play basketball around power lines. Make a slam just a little too hard and it hits the wire and fuses in place. They would have to shut down the juice to get them off and that's a hassle so they'll leave them up.
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# ? Dec 14, 2012 17:31 |
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grover posted:If you're referring to what I believe you are, they're so aircraft can see the power lines are there. The lines are below the level of the tree line though and there used to be a four story hospital next to those lines until the hospital was destroyed by a tornado.
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# ? Dec 14, 2012 17:33 |
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SlayVus posted:The lines are below the level of the tree line though and there used to be a four story hospital next to those lines until the hospital was destroyed by a tornado. grover fucked around with this message at 17:37 on Dec 14, 2012 |
# ? Dec 14, 2012 17:34 |
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grover posted:Did that hospital have a helipad? Yes It still doesn't make sense though.... even though you are correct it seems on your first statement. The lines are lower than the helipad would have been.
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# ? Dec 14, 2012 17:34 |
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SlayVus posted:Yes
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# ? Dec 14, 2012 17:37 |
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As a pilot who does a bit of low altitude flying I can assure you that power lines are loving invisible. The lines might be lower than the treeline now but don't forget that trees grow and most power infrastructure is rather old.
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# ? Dec 14, 2012 22:01 |
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This is a video that mentions the markers. https://www.youtube.com/watch?v=E-bU8dHwSFo&t=1080 There was also an electrocution in that video as well, 480V https://www.youtube.com/watch?v=E-bU8dHwSFo&t=2075 Drawing maintenance is absolutely critical in electrical systems. It's easy to make changes ("The box was cramped so instead of running the cable to breaker 12 we ran it to breaker 16.") can result in disasters. (That and always using your Volt Alert or meter to check.) I recently had a problem with a control circuit, and I found that a simple short-cut taken (ganging two wires on one contactor terminal instead of using separate, isolated terminals) created a sneak-circuit. That circuit caused a PLC to indicate that the system was in one state when it was really in another state. (To be fair, in my original design I made the same mistake until someone more experienced pointed it out.) I looked at the schematic and immediately realized what the electrician did, opened the box, and did see two wires on one terminal. I explained the error to them, and consoled them in the fact that I made that mistake too. Three-Phase fucked around with this message at 13:26 on Dec 15, 2012 |
# ? Dec 15, 2012 13:12 |
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That 480V electrocution video is why you should always meter a circuit even after you think it's isolated. I also hate that the narrator said "440 volts of current passed through his body"...
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# ? Dec 15, 2012 23:49 |
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Anti-Hero posted:I also hate that the narrator said "440 volts of current passed through his body"... Yeah, that's up there with "Victim is recovering from his electrocution".
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# ? Dec 16, 2012 13:35 |
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What are the common components of your average everyday city substation? Also, what are the common components of the larger regional ones?
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# ? Dec 26, 2012 10:58 |
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virtual256 posted:What are the common components of your average everyday city substation? I have trouble differentiating between those two, but I'd say things like circuit breakers, isolators, capacitor banks, line reactors, transformers, and control houses.
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# ? Dec 28, 2012 00:19 |
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Three-Phase posted:I have never actually seen corona discharge, but I've heard it walking underneath 345kV lines. You should hear the Jackson Ferry-Wyoming interconnection some time. It's got 6 lines per phase, which is supposed to make it quieter, but, at 765 kV, the sound is impressive (and awesome).
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# ? Jan 3, 2013 01:31 |
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So this came up in the Bitcoin thread in GBS, I thought it was topical and should be cross-posted here:TheColorBlue posted:What is the likelihood that this monstrosity manifested out of buttcoin mining? This is apparently a place of business, so... Can anybody here explain why, exactly, someone would want to cool down their breaker panel? Edit: Woops, sorry. FrozenVent fucked around with this message at 21:30 on Jan 7, 2013 |
# ? Jan 7, 2013 21:01 |
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Umm that's a breaker panel, not a fuse box. And if I had to guess, I'd say that fan is some idiot's idea of moisture abatement.
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# ? Jan 7, 2013 21:27 |
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I was thinking either they're running a circuit right at the ragged edge and are trying to cool the breaker down so it doesn't trip, or they've got a shoddy breaker that needs to be replaced because it heats up when it shouldn't. Either one seems monumentally stupid to me.
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# ? Jan 7, 2013 22:02 |
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FrozenVent posted:So this came up in the Bitcoin thread in GBS, I thought it was topical and should be cross-posted here: I'm thinking someone reset a tripped breaker and noticed how hot the motherfucker was, but instead of fixing it, rigged up a fan. Stupid.
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# ? Jan 7, 2013 22:14 |
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Can't wait to read about that in the inevitable OSHA fat/cat report.
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# ? Jan 7, 2013 22:38 |
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I'm cooking up something special on electrical hazards. I want to make sure I haven't missed anything. Here's my list: Electric shock -Ohm's law and current effects -GFCIs and other safety items -Ungrounded/grounded systems (elevated voltage during a fault) Electrical safety history -Early systems and dangers -"Mixed voltages" on overhead wires -"Jones is dead!" (Square D) and knife switches -Hazards in earlier systems (metal case connected to neutral, exposed machinery, moving machinery) Arc flash -Effects -PPE (NFPA 70E) -Reduction (fuses, trip settings, current limiting devices like reactors) High voltage -Voltage gradient on downed line -Hopping/shuffling -Rubber mat use, safety grounds, etc. -System misconfiguration Meter safety -Meter category (I - IV) System safety -National electric code NFPA 70 -Electrical fires -Generator backfeed Am I missing anything good? Three-Phase fucked around with this message at 12:45 on Jan 24, 2013 |
# ? Jan 24, 2013 12:43 |
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Only thing that immediately comes to mind for me is arc flash boundaries. Perhaps ladders/lifts/scaffolds, too, w/r/t overhead lines.
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# ? Jan 24, 2013 14:59 |
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power suppply isolation, or is that part of grounded/ungrounded?
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# ? Jan 24, 2013 18:25 |
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peepsalot posted:power suppply isolation, or is that part of grounded/ungrounded? Could include that with grounding. One of the comments is about how on a delta system (like 480V) there's no such thing as true isolation, in fact the "line to earth" voltage is the same as line to line.
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# ? Jan 25, 2013 02:23 |
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Stored energy in disconnected systems. This can range from the obvious such as batteries and capacitors, through subtle cases like rotational inertia of motor-generators, to weird stuff like superconducting solenoids. Also, X-ray hazards from vacuum HV discharges.
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# ? Jan 25, 2013 07:44 |
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Stored energy - that's good too! One additional thing I considered is "mission-critical" electricity where a supply or power quality problem could lead to death. Things like: 1. Life-support and medical systems at a hospital 2. Ventilation fans in a mine 3. Fire pumps 4. Military systems (melt before fail and battle short)
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# ? Jan 25, 2013 12:46 |
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# ? May 13, 2024 04:55 |
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I'd put under arc flash reduction a site survey and arc flash analysis using computer aided tools. You don't have to get too in depth about it, but mention that in complex electrical systems it is the only way to get a somewhat accurate picture of the arc flash hazards.
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# ? Jan 27, 2013 19:02 |