[HN Gopher] Gzip exceptions, but only on hot or rainy days ___________________________________________________________________ Gzip exceptions, but only on hot or rainy days Author : polygot Score : 197 points Date : 2022-11-12 07:58 UTC (15 hours ago) (HTM) web link (alexyorke.github.io) (TXT) w3m dump (alexyorke.github.io) | gene91 wrote: | The author appears to be in Vancouver BC Canada. | | In US/Canada, it is safe and code compliant to have floating | ground in a GFCI protected outlet. The GFCI provides the safety | benefit that ground is supposed to provide. Obviously having both | GFCI and ground is better, but having only the former is allowed. | Occasionally, ground serves additional purposes beyond safety, | but that doesn't apply for a computer power supply. | | Additionally, in US/Canada, it is unsafe (and against code) to | wire a new outlet directly to water pipe. Ground-neutral bond is | required at the main service panel because the "ground" (soil, | water pipe, etc) isn't a good enough electricity ground. The | ground wire in the outlet must be wired to the main panel | (directly, or through subpanels), where 3 things are connected | together: neutral bus, ground bus, and the "ground" (soil, water | pipe, etc). | | All in all, the author didn't find the root cause of the problem. | And in trying to fix the problem, the author introduced more | bugs. | CGamesPlay wrote: | I have a similar electrical issue at my house as well. I plug my | laptop over I USB-C into my AC-DC converter, which comes with a | two-prong US power cable, which is connected to a two-prong US-EU | adapter, into a power strip connected to the wall (EU outlet). My | laptop wrist rest is also "spicy" (most noticeable if my | girlfriend touches my arm when I'm typing, we will both get | shocked). So I obviously have a grounding issue but I'm at a loss | because the equipment doesn't have anywhere to attach a ground | rail to. Any suggestions? | felurx wrote: | I'd try using another power supply, ideally one that has a | ground connection. | V__ wrote: | > A quick check with a $10.00 outlet tester confirmed that there | was a grounding issue. The tester confirmed that there was no | ground. | | > send in an electrician this time. They asked lots of questions, | and then recommended that my air conditioner stay on a different | outlet because there were two circuits. I tried this for a few | days, but the issues still reappeared. | | Either something is missing or both the author and the | electrician are absolutely insane. There is a grounding issue, | which could mean anything from a broken outlet to incompetent | wiring throughout the house, and they aren't thinking about | fixing it immediately? Let's try a workaround for a few days? I | have no words. | nfriedly wrote: | I expect it's the landlord instructing the electrician to do a | half-assed job to keep the cost down. | dehrmann wrote: | Except multiple visits are expensive, and no one wants the | place to burn down. | colechristensen wrote: | And shouldn't there be exactly one grounding point per building | and definitely not one outlet randomly grounded to a pipe? Not | an electrician but I'm pretty sure that's a major code | violation and safety hazard. | cwillu wrote: | Pipe is a great ground, if done properly. Nice big hunk of | metal thoroughly embedded into the ground is all a ground | plate is. | otikik wrote: | The problem with "if done properly" is that you actually | have to go and check. If you just "hope that it is done | properly" you can have a lot of surprises, like lights | going out when the sink gets full of water. Or spicy | dishwashers. | | If you don't know whether it's properly done, it's much | more efficient to throw a ground cable from the nearest | service junction than it is to "hope" and then have to fix | things later. | colechristensen wrote: | It's not about whether or not pipe is a good ground. The | electrical grounding for a building needs to be like a | tree. No ground loops and exactly one grounding point. | Arbitrarily adding grounds, especially through water pipes | can do things like making all of the piping and water in | the house hot if there is a fault somewhere and it | definitely seems like that's the case here. | | The whole idea is that the ground wire is the least | resistance path for stray current to go to. When you have | separate ground paths there can be a dangerous potential | between ground wires and the least resistance path for | stray current can again be you. | murderfs wrote: | There's a difference between the electrical return path | (aka neutral) and protective earth (aka ground). Earth is | purely for safety: you earth the metal chassis of | appliances so that if for some reason they get shorted to | hot, the current has a low impedance path to earth and | your breaker will pop. It's perfectly acceptable to have | an independent earth at every single outlet, as long as | you're earthing to an acceptable source (which, AFAIK, | means driving an earthing rod into the ground, because | pipes aren't legal in the NEC anymore). | sidewndr46 wrote: | The "single ground point" is some sort of weird | misconception of how ground systems work that became an | urban legend. I think it comes from the fact subpanels | used to be allowed to bound the neutral and ground and | that putting a ground rod there created another return | path for current from the neutral. | icehawk wrote: | You can have multiple ground points per building as long as | the ground points are bonded to each other. | | You can only have a SINGLE tie between neutral and ground. | | What we don't know here is if the piping is tied to a | grounding rod, or if there is a grounding rod or if the | piping is the ground point. | chrisseaton wrote: | > definitely not one outlet randomly grounded to a pipe? | | That's how it used to be done! Remember a lot of houses were | built before electricity and it's been retrofitted over time. | doubled112 wrote: | A water pipe is bare copper straight to the ground. | | It makes perfect sense if you think about it. | | Pretty sure that is how it is done in my much newer than | electricity build. | loeg wrote: | Old copper water pipes, yes. Obviously you can't ground | using a PEX pipe. | rpvnwnkl wrote: | I think the continuous water still maintains a ground | path even in pex | bombcar wrote: | Water is actually not very conductive at _all_ which is | why you need to install ground links if you break into an | existing _grounded pipe_. | | And the purpose of grounding the pipe isn't to use the | pipe as a ground (some very old electrical setups may | have done this), it is to prevent the pipe from getting | energized by a wire or something resting against it. If | the pipe is properly grounded, that'll short out a | breaker. | cesarb wrote: | Wouldn't it also need a continuous copper pipe until it | meets the ground? A pipe being made of copper or iron | doesn't mean it's not connected to a plastic pipe or | adapter upstream; and I've seen plumbers using a rubbery- | looking tape between the threads when screwing two metal | pipes together, which might not be conductive. | loeg wrote: | > Wouldn't it also need a continuous copper pipe until it | meets the ground? A pipe being made of copper or iron | doesn't mean it's not connected to a plastic pipe or | adapter upstream | | Right. | | > I've seen plumbers using a rubbery-looking tape between | the threads when screwing two metal pipes together, which | might not be conductive | | Probably PTFE (teflon) tape. | | The thing to do with oldschool copper pipes though was to | braze them together, which is conductive. | finnh wrote: | I just fixed this situation in a house from the 70s. | Cable coax lines grounded to a metal hose bib ... which, | in the crawl space, switches to PEX about a foot away | from the bib. | | Cable guy installing high speed internet was all "nope!". | I think the previous owners just had crap internet and | didn't ever get into why. | sidewndr46 wrote: | The coax shield must be broken somewhere between you and | the service provider. "Grounding" a coax to PEX should | never make a difference in any way. | finnh wrote: | I think part of his worry was lightning strike busting | their equipment. Unsure about the rest. | bbarnett wrote: | Some old house, wired not understanding ac, mixed up the return | and ground. Stuff works, but... | masklinn wrote: | Seems like a completely slapdash piece of work really: | | > They asked lots of questions, and then recommended that my | air conditioner stay on a different outlet because there were | two circuits. | | An AC has sufficient power draw that you'd normally put it on | its own, exclusive, circuit. Like a drier or washing machine. | Not on whatever random outlet is nearby. | Gracana wrote: | Probably talking about a window unit there. | bombcar wrote: | And even then if you've been anywhere with "fun" power | you've noticed the lights dim when any beast of a machine | turned on. | | The US grid has gotten better, and machines have too, but | lights used to dim all the time. | trebligdivad wrote: | I suspect both; I mean who worries about gzip when their | touchpad is 'spicy'! | Lukas_Skywalker wrote: | MacBooks and iPads had the "spicy case" issue for quite a | long time. In certain countries, the Apple power supply comes | with two adapters for plugging it into the wall - one with | two contacts, and one with three contacts. Only the one with | three contacts is grounded. | | When using the ungrounded adapter, the entire case of my 2011 | MacBook Air and the iPad 2 got slightly "spicy", although it | felt more as if the case suddenly changed texture and was | more wavy (probalby an artifact of europes 50Hz mains | frequency). | | The strangest thing was turning on my touch controlled desk | light while working on the laptop. If I touched the light and | the laptop at the same time, the light shocked me quite | noticeably. | derefr wrote: | I really wish the North American adapter's direct-to-wall | connector (the one that's not a cable) came in an optional | 3-prong configuration. As it is, I have to bring an extra | cord around with me any time I bring my laptop somewhere, | simply to ensure it's grounded. (I used to get those shocks | from it too, until I did, and I really don't want to go | back to them, let alone know what they're doing to the | electronics.) | bombcar wrote: | Try aftermarket? https://smile.amazon.com/Grounded- | Duckhead-Apple-Mac-Adapter... | | Shouldn't be able to hurt you THAT much ... | nottorp wrote: | Hm interesting. I'm in europe on 50 Hz, none of my apple | power adapters are grounded, not even the mac mini power | cord is, and i've never noticed any issue. | | However the electrical wiring for my apartment is only | about 20 years old... | Lukas_Skywalker wrote: | Apple might also have improved this for newer devices. I | remember it being a problem for devices from around 2011 | to 2014. | | Edit: MertsA added some more info below: | https://news.ycombinator.com/item?id=33572585 | berkut wrote: | 2021 MBP 14 has this issue for me with the stock charging | brick (NZ - which has 3-pin sockets): but Apple don't | ship the stock charging brick with an extra extension to | the socket, so the transformer/brick plugs (via a corner | adapter) _directly_ into the socket, which isn 't | grounded. | | If I replace the direct corner adapter of the brick with | an older (from a 2015 MBP 15) extension which is | grounded, i.e. you can't then literally plug the charging | brick directly into the power socket, there's an | "extension" chord in between (and not just a generic one, | this is Apple specific for the connector to the brick), | the issue goes away. | whimsicalism wrote: | Definitely still occurred on my 2017 macbook pro. | Macha wrote: | Still occurs with my 2021 M1 MBP | BuildTheRobots wrote: | I've noticed "textured screen when charging" on a range of | mobile devices which I've nearly always been able to | correlate with cheap USB chargers. Other family members | seem oblivious, though to me it's clear as night and day. | solarkraft wrote: | I thought one of the two wires should be equal to ground? | actionfromafar wrote: | That's how it could be done in theory but it's never | because you would kill people. | | Instead one wire is neutral, one is phase, and the third, | optional, is ground. | galangalalgol wrote: | Can you supply a good "this is how it actually works" | reference for European electricity? | | In the US there is one neutral and one hot line. Then | there is the ground that is grounded at the box | preferably. You can sometimes have a 240 line split to | feed two 120 outlets where the hot lines from each are at | a 240 difference to each other. If one line has a large | load relative to the other, the neutral won't be that | close to ground. Is that was is happening with these | laptops? | xxpor wrote: | >If one line has a large load relative to the other, the | neutral won't be that close to ground. | | Shouldn't it still be pretty close voltage wise? If we | hold the neutral is always at 0v at the panel, since | that's where it's tied to ground, the voltage on the | neutral between the panel and the outlet should still be | pretty low because copper wire has a pretty low | resistance (by V=IR). I'd have to break out my calculator | (and look up the actual standard values of copper wire | resistance), but I'd guess even >20V would be quite | unusual without some other fault... | lupire wrote: | Why would it kill people? | bombcar wrote: | https://portablepowerguides.com/ground-to-neutral-both/ | | Because it can cause power to go unexpected ways. | | All the "power safety" stuff does _nothing_ if everything | is correct and perfect, but if it fails, and ground and | neutral are bonded anywhere EXCEPT at the panel, you can | get power flowing through _you_. | dthul wrote: | I noticed the same issue. But does the ground connection of | the wall plug side of the transformer actually make a | difference? I'm not good with electrics but I always | thought the other side of a transformer is electrically | isolated and the sides don't share a ground. | ScottEvtuch wrote: | I think some AC to DC transformers bond the AC neutral | and the DC negative. | asddubs wrote: | it's because of the current that is leaked by the class y | capacitor connecting primary and secondary of the power | supply to suppress EMI. this will mean there's something | like 50 - 100v potential to earth on your macbook, but at a | very low (non dangerous) current. that's why you get zapped | or feel a tingle. if you have the earth connection, that | power will be sunk through the earth lead, but otherwise a | metal case will generally be connected to the DC ground | (and also earth if present on the plug), which will have | this low current AC voltage present. | TacticalCoder wrote: | > MacBooks and iPads had the "spicy case" issue for quite a | long time. In certain countries, the Apple power supply | comes with two adapters for plugging it into the wall - one | with two contacts, and one with three contacts. Only the | one with three contacts is grounded. | | Thanks a _lot_ for you comment. I had noticed that myself | with two old Mac Book Airs.. Actually, that 's how I knew | if plugs were grounded or not: I could immediately tell. | | But, over the years, I always wondered if there were any | electrical issue (in several houses) or if it was normal. | bombcar wrote: | It's not "normal" but it may be common. The MacBook | should be fine on two wires; but something _else_ may not | be, causing it to be spicy. | lostlogin wrote: | They are spicey everywhere though, even in cardiac | protected areas that are checked regularly by | electricians. New builds, rebuilds etc. | | This isn't a building wiring issue. | leguminous wrote: | I noticed this when I was playing guitar and using my | laptop at the same time. The strings and bridge on an | electric guitar are grounded. When I had my arm touching | the bridge and I put my hand on the MacBook's case, I would | get a mild shock. | | I measured the voltage difference and, if I recall | correctly, it was something like 20V. I started using the | 3-prong adapter and haven't had any more issues. | ZoomZoomZoom wrote: | You should absolutely make a habit of not touching | anything else as long as any part of your body touches | the strings, bridge, tuners or other conductive parts of | the guitar. This includes not touching the mic grill with | your lips. This is why singing guitarists should keep a | foam mic cover handy. It's also the reason keeping your | spring cavity closed (if you have one) is a good idea. | | In many places electrical wiring in homes is just two | wires and what wiring monstrosities await you in shabby | clubs and shady rehearsal spaces is just beyond belief. | Be safe. | KMnO4 wrote: | This is not necessarily true depending on code. Some builds do | not have grounded outlets as long as a GFCI is installed at the | distribution. | | It's weird and unnatural, but there's nothing inherently wrong. | bastawhiz wrote: | Saying there's "nothing wrong" when there are obvious, | serious hardware issues and a UPS that won't stop beeping is | like saying "well there's no law that my tires can't be bald, | so I'll keep driving because there's nothing wrong" | mannykannot wrote: | I do not think the situation is the same. I believe GFCI | gives excellent protection against shock even if the ground | is faulty and the neutral is floating with respect to | earth. (Nevertheless, I still want my home to have properly | grounded three-pin sockets, even if it is implausible that | it will ever make a difference.) | | I hope an expert can chime in, but I suspect a 'spicy' | trackpad would trigger GFCI. | SAI_Peregrinus wrote: | GFCI at the breaker should have the ground tied to | neutral, and still have grounds on the outlets (tied back | to the GFCI at the breaker). Current through the ground | pins will trip the GFCI, rendering the system safe. Since | the ground pin should be bonded to any exposed metal | (e.g. aluminum laptop case) a fault leading to a "spicy | touchpad" should instead shut off the entire circuit at | the breaker. | | Just slapping a GFCI in without that bonding won't do | anything though. The ground would be floating, and thus | wouldn't ever trip the GFCI. There would be no path | through the GFCI for the fault current to take, making | the system just as dangerous as having an ungrounded | conductive case. | | A "double insulated" system has non-conductive material | for the case of the electrical device and only needs a | two-pin polarized plug. A fault of live to case won't | cause danger, because the case is an insulator. A fault | of live to neutral will just blow the device's internal | fuse (or trip the breaker if the device has no fuse, but | the breaker is just to protect the romex wiring in the | walls so the device could well be on fire by that time). | dreamcompiler wrote: | A GFCI device does not care about the presence of a | ground current -- at least not directly. GFCI measures a | current imbalance between hot and neutral; if there is | such an imbalance, it disconnects the circuit (i.e. it | trips). | | It's true that any such imbalance is most likely to flow | through the ground of the GFCI's own Romex cable and for | that reason it's best for GFCI circuits to be grounded. | But an ungrounded GFCI will also trip if its hot current | finds another path through ground, such as through a | water pipe, because that current will not be returning | through the GFCI's neutral and it will thus create an | imbalance. | bombcar wrote: | https://www.angi.com/articles/does-replacing-ungrounded- | outl... | | GFCI specifically works by measuring the current out = | current in. | | To be shocked, current out [?] current in. | sidewndr46 wrote: | There is actually a weird way to work around that. If you | stand on an insulated sheet (like a clean plastic cutting | board) you wouldn't have a path to ground. If you cut | open one current carrying conductor of the cord and put | yourself in-series a GFCI wouldn't trip in that case. | Current would still flow through the device. Enough to | hurt you, but probably not enough to turn it on for most | devices like a lamp. | | As you can guess, such an accident is nearly impossible | even in the case of someone cutting through a cord | accidentally. | bombcar wrote: | Similarly arc fault detectors try to detect arc faults | which a GFCI won't "see". | mannykannot wrote: | > The ground would be floating, and thus wouldn't ever | trip the GFCI. There would be no path through the GFCI | for the fault current to take, making the system just as | dangerous as having an ungrounded conductive case. | | GFCI works by detecting an imbalance of current on the | intended path - i.e. between live and neutral. For an | ungrounded conductive case to create a electrocution | risk, there must be an alternative pathway through the | user's body and a potential difference to create a | current on that pathway. Whenever these conditions occur, | there will be a live-neutral imbalance which will trip | the GFCI before any harm is done. In contrast, with an | ungrounded conductive case and no GFCI, if a fault | creates a situation where electrocution is possible, the | only thing that could protect the victim is the circuit | breaker, but the breaker must allow sufficient current | for normal use, which is well above the threshold for | lethality. | sidewndr46 wrote: | I highly, highly recommend you read up on electrical | theory. When you're done go de-energize a system, | disconnect the ground on a GFCI outlet, then connect the | live of that GFCI to whatever piece of random material | you have. Or lay it on the ground directly. When you re- | energize the system, the GFCI will trip or it is bad. | | If a GFCI was dependent on a device being grounded it'd | be no better than a regular 3 prong outlet. We'd also | have to ban 2-prong devices, which are probably most | devices in a US home at this point. | bornfreddy wrote: | > I highly, highly recommend you read up on electrical | theory. | | Do you have any suggestions on books, tutorials or | similar? | jaclaz wrote: | It probably depends on local codes, but: | | >and the outlet was _correctly_ grounded using my water heater as | ground, according to my outlet tester. | | I don't think that grounding to a water heater (please read as to | water plumbing) is _correct_. | dtgriscom wrote: | Back in the day, I remember reading instructions on how to | build some sort of electrical toy (a Tesla coil? can't | remember). The circuit was 120VAC powered, with a hot side and | a neutral side. | | The problem was that the neutral side was accessible to the | user, and the plugs back then were unpolarized. So, if you | plugged the "neutral" side of the plug into the "hot" side of | the outlet, you would Have A Bad Day. | | The workaround: only wire the "hot" side to the plug, and | connect the "neutral" side via a separate wire to a nearby | radiator (presumably ground). That way, plug the plug in wrong | and the toy wouldn't work, rather than becoming dangerously | charged. | | Was it safe? Safe enough for back then... | jaclaz wrote: | >Was it safe? Safe enough for back then... | | Yep, but back then we were much more reckless, just the other | day there was a story on HN on amateur chemistry (dying or | dead): | | https://news.ycombinator.com/item?id=33517520 | | About electricity, up to not so many years ago (here in Italy | up to around 1990) electrical codes were fairly "open", with | no ground/earth requirement, and up to the 1970's or so it | was not so uncommon to have houses with external wires, see: | | https://news.ycombinator.com/item?id=29616691 | | How we (kids in the '60's and '70's) managed to largely | survive these and all the other everyday risks (no helmet on | motorbikes, no safety belts in cars, etc.) remains a mistery. | | But in the case reported here that today an electrician would | ground an outlet to water plumbing, it would be - well before | being forbidden - unthinkable of. | 13of40 wrote: | > amateur chemistry | | Ah, those were the days. Back in the 80s my parents bought | us a chemistry set from a thrift store that was probably 20 | years old already. It was actually set up to teach some | practical chemistry by providing a mystery substance and a | set of reagents that would help you figure out what the | substance was. Ten year old me just cut to the finish line | and tasted the mystery substance - it was sugar. | Gracana wrote: | Are you sure it didn't have a normal plug, with a separate | clip for a reliable chassis ground? I don't see how the half | plug with a neutral wire to a radiator would be "safe", even | when compared to a neutral-connected chassis with an | unpolarized plug. "The hot side is accessible to the user" is | still true, just remove the wire to the radiator, now it's at | line potential. | Waterluvian wrote: | My grandpa's old home only had ground pin outlets in rooms with | plumbing because they only wired them up to pipes. I could | imagine some wild old codes allowing that kind of thing. | marcus0x62 wrote: | Grounding to a cold-water pipe is pretty common in the US, and | is allowed under certain narrow circumstances by the national | code (subject, of course, to being disallowed by local codes.). | Specifically: | | NFPA 70 | | 250.52(A) Electrodes Permitted for Grounding. | | (1) Metal Underground Water Pipe. A metal underground water | pipe in direct contact with the earth for 3.0 m (10 ft) or more | (including any metal well casing bonded to the pipe) and | electrically continuous (or made electrically continuous by | bonding around insulating joints or insulating pipe) to the | points of connection of the grounding electrode conductor and | the bonding conductor(s) or jumper(s), if installed. | coryrc wrote: | Even more so, it's usually mandatory to ground your panel to | incoming water line when it is metallic. But that's for the | electrical panel, not a single random outlet. | marcus0x62 wrote: | Sure, but that's about providing a ground path for the | water line in case it becomes accidentally energized, not | necessarily providing a ground electrode for the electrical | service. In other words, you'd have to do that even if the | metal water piping was not eligible to be used as a ground | conductor: | | NFPA 70 | | 250.104(A)(1) General. Metal water piping system(s) | installed in or attached to a building or structure shall | be bonded to any of the following: | | (1) Service equipment enclosure | | (2) Grounded conductor at the service | | (3) Grounding electrode conductor, if of sufficient size | | (4) One or more grounding electrodes used, if the grounding | electrode conductor or bonding jumper to the grounding | electrode is of sufficient size | | The bonding jumper(s) shall be installed in accordance with | 250.64(A), 250.64(B), and 250.64(E). The points of | attachment of the bonding jumper(s) shall be accessible. | The bonding jumper(s) shall be sized in accordance with | Table 250.102(C)(1) except that it shall not be required to | be larger than 3/0 copper or 250 kcmil aluminum or copper- | clad aluminum and except as permitted in 250.104(A)(2) and | 250.104(A) (3). | TacticalCoder wrote: | I noticed that with my two 2012/2013 MacBook laptops overall | several european countries, in different homes: that "twitchy" | feeling on the metal case of the laptop when plugged without | grounding. | | Do all of these houses have serious electrical issues? | | The house in which I live now does that to my old MacBook Airs if | I convert my Macs's chargers' hybird CEE 7/7 plug (two poles + | grounding) to a flat two-pole europlug (no ground). | | I can reliably reproduce the issue _in several houses, over | several countries_. | | But if the plug is grounded, everything _seems_ normal. | | What's going on? | | I'm here since six months, with shitloads of electrical things | ongoing (including the whole swimming pool machinery). And | everything appears to be working fine. | | Should I be worried? | | I mean: I can reliably reproduce what TFA describes. My old | MacBook Airs do that all the time if there's no ground. | [deleted] | sdflhasjd wrote: | I've come to the conclusion that Apple and all their "amazing" | engineering doesn't actually know how electricity works, | because these silly issues plague their products. | | The fuzzy MacBook is pretty annoying, but how about the Mac | Studio, which can trip a GFCI when plugging it in (which, as | far as I can tell, it almost certainly a design flaw and not a | fault with my particular unit) | | I expect this kind of stuff from the tat bought on eBay, where | it's promptly thrown in the bin. | hinkley wrote: | Floating earth ground definitely leads to tingly problems with | some macbooks. My guess is some sort of capacitive discharge | issue with some of the designs, but others have definitely | noticed this problem. | | The two prong connector was always a bad idea, but frayed | wiring on the charger or bad house wiring can also cause it to | float. | pmontra wrote: | TL;DR grounding issues. | | Nice read of all the debugging and resolution steps. | throwaway9870 wrote: | > Aside: At this point, my laptop was bordering on unusable, even | on battery power. | | How would grounding an outlet affect a laptop running on battery? | Aeolun wrote: | Author mentions they replaced the laptop, so I guess at that | point it was well and truly cooked by all the issues before. | JelteF wrote: | Reading this gave me flashbacks to the time when I tried figuring | out why my laptop keyboard was typing letters by itself randomly. | Turns out the always-on-usb feature of the laptop was causing | some short circuiting: https://forums.lenovo.com/t5/Lenovo-P-Y- | and-Z-series-Laptops... | im3w1l wrote: | Uhm I find the conclusion here quite unsatisfactory. Like I have | plugged in many things without grounding and never had issues | like this. It sounds to me like there were more issues that are | now masked by working grounding. | bmicraft wrote: | Yeah, it sounds like the neutral wire wasn't at 0V either. | thriftwy wrote: | In the ex-USSR there was usually no grounding at all. All plugs | had just 2 pins. Even if the socket is new, the wiring most often | isn't. | | Everything works mostly normal, except that you can have 110 | (220/2 via capaciator bisection) volts with large impedance on | "supposedly grounded" metal surfaces to give you minor | shocks/uncomfortable feeling. | brianwawok wrote: | My house built in 1950s in the US is the same. Grounds were't | in style yet. | | There are very few things that actually need grounded. Kitchen | appliances and laundry (which are both retrofitted with | grounds). | amluto wrote: | Oof. A missing equipment ground (the third pin on your outlet or | its wiring) will not cause these issues. In fact, it's _legal_ to | have an ungrounded three pin outlet in a retrofit situation as | long as it's GFCI protected and labeled. | | I bet there's a missing or poor _neutral_. If your neutral wiring | has problems, then you are operating at anywhere between 0 and | 240 VAC depending on what else is going on, e.g. whether the AC | is running or the lights are on. Additionally, if you _do_ have | any sort of ground and that ground is (improperly) tied to | neutral in more than one place, then you may have substantial | current flow through "ground", i.e. the actual Earth, your pipes, | your steel building structure, your body, etc. | | Get a true RMS voltmeter, (safely!) connect between hot and | neutral, and switch lights and AC on and off. Repeat with the | meter between neutral and ground. | | And consider replacing the circuit breaker on the circuit you're | using with a GFCI breaker. Several common screwups will cause it | to trip. | devwastaken wrote: | To my understanding a ground isn't necessary for equipment to | operate at all, however it sinks the EMI, reducing floating | neutral voltage and noise. | | PC equipment such as voltage regulators put out a lot of noise. | The neutral is not bonded to the metal chassis when a ground is | not present, meaning the difference in potential in the chassis | cannot be synced with ground, causing various crazy issues. | It's why cases still are overwhelmingly metal, steel mostly. | lazide wrote: | Ground is (ideally) a just in case safety measure. It catches | voltage transients, shorts, etc. and routes them safely to | ground via a (normally) non-current carrying conductor. This | is also useful for EMI protection. | | The neutral should also be bonded to ground at the panel in | residential installations. | | It used to be there was no ground, and neutral carried the | 'return' load and was also used for equipment grounding and | the like. It's not as terrible an option as you'd think, if | everything else is done correctly. | | However, this can be dangerous as certain types of wiring | setups (generally incorrect and non-code compliant) can | produce voltages on other neutrals in the circuit, and if | that is being used to ground a metal case (which there is no | other alternative), zap to anyone who touches it. | | Especially if someone wired something backwards and you get a | hot neutral (aka now hot metal case). Especially if the badly | wired thing is something sporadic, like a rarely used light | switch or outlet. It turns it into a ticking time bomb. | | It's a somewhat common DIY error to create floating grounds | (and floating neutrals), and a floating ground can still | cause this even with modern wiring with the right kind of | screw up. | | It's one of the most dangerous types of wiring problems. | | I've run across it in two different houses I moved into after | the fact. Also damaged conductors causing heat and sparking. | Also damaged outlets that on closer inspection exposed | current carrying parts of the sockets due to cracked and | broken plastic. | | It's a jungle out there! | lostlogin wrote: | > Oof. A missing equipment ground (the third pin on your outlet | or its wiring) will not cause these issues. In fact, it's legal | to have an ungrounded three pin outlet in a retrofit situation | as long as it's GFCI protected and labeled. | | I'm pretty sure that this is location specific and I don't | think this was pass where I am. Even outlets which aren't RCD | protected get a fail now. | murderfs wrote: | A bad neutral isn't going to trigger a brownout that reproduces | reliably in some random gzip code when you're booting fully | into Windows, on a modern CPU with fine grained | frequency/voltage scaling, on a battery-powered laptop, powered | by a switched-mode power supply with tons of capacitance in | every single layer on the way to the CPU. | | The most plausible explanation I can think of would be if the | return current is flowing through the monitor and EMI from that | is disturbing things, but 60Hz might as well be DC to modern | signal rates, so that's tantamount to blaming witchcraft. | fastaguy88 wrote: | That is exactly what bad neutrals do (produce brown-outs). | They produce brown-outs because the potential between the | "hot" side and neutral is < 120 V, because the neutral is > 0 | V. | murderfs wrote: | Yes, it'll produce a brownout at the outlet, but it's | highly unlikely that this will manifest as a brownout at | any of the component voltages, because there are so many | layers of filtering. That <120V goes through a switched- | mode power supply which converts that down to 20ish V, | which goes to a battery charger IC which charges the | battery, which outputs a variable voltage that goes through | multiple more layers of monitored DC/DC conversion to | generate the power rails. Every one of these steps has | circuitry that will panic and send a signal to the main | PMIC if it sees a voltage that is out of spec. | cesarb wrote: | My guess would be that the issue was not brownouts, but | noise (which could even have peaks well above 230V). The | air conditioner has a motor, and motors can be | electrically noisy; it should have filtering, but with a | broken neutral, that filtering might not have been as | effective. Grounding the outlet with the computer (the | solution at the end) would have allowed the filters at | the computer and monitor power supply to filter out the | noise (AFAIK these filters work mostly by shorting high- | frequency components of the waveform to the other wire | and/or to ground, so they need a good neutral and/or | ground to work). | | But yeah, these sorts of "bad wiring" situations can have | baffling effects. I would love to see someone in one | these situations actually manage to get a logic analyzer | trace or similar to show what's actually going on with | the power supply, together with an investigation (and | fix) of its real cause. | pencilguin wrote: | Anyway, disgraceful that the electrician failed to | diagnose Al or any of it on the first visit. | kcexn wrote: | Most residential power is dirty to some extent, and AC/DC | converters are supposed to be able to cope with a wide | range of input distortions. For the problem to have | worked its way through all of the safety components in | both the laptops power brick and its internal electronics | means that the distortions must have been particularly | high amplitude, and at frequencies that couldn't be | easily filtered out (very high, very low, or both). | | Electricians that aren't particularly well trained, or | particularly experienced are probably not going to be | able to diagnose this kind of problem. | | This is really a problem for an electrical engineer. | | Unfortunately, in most jurisdictions, engineers aren't | allowed to perform these kinds of repairs because they | don't necessarily have the certifications to perform work | on live wires. | | Most electricians can only trace wires and identify | visible faults, and replace things that aren't up to | building codes. | gene91 wrote: | The author appears to be in Vancouver BC Canada. | | In US/Canada, power supply is done via 240V split phase. | Therefore, a broken neutral between service and home would have | lead to a 120V outlet getting anywhere between 0 and 240V AC. | That sure would have lead to something a lot less pleasant than | just gzip errors. | ilyt wrote: | Interesting, most notebooks are _not_ connected to ground. Maybe | ground connection came from peripherals (USB Hub /monitor etc.) ? | | > Again, the same pattern came up: the wrist-rest was only | uncomfortable when running on AC power. | | Guy's getting lightly electrocuted... | laputan_machine wrote: | lightly shocked, lightly electrocuted is like being lightly | decapitated. | | We actually have this issue in our 6 year old office, so not | exactly old electrics. Running laptops off non-grounded plugs | causes that typical "vibration" / buzzing feeling throughout | the chassis of the laptop. | wolletd wrote: | I think it was a notebook with aluminium frame, which would | make grounding appropriate. | | I had a Dell XPS 15 with aluminium frame once and discovered | that it was grounded when I was in a hotel abroad with no | ground on the outlets and - my wrist-rest got uncomfortable. | | I then quickly fudged some wire from the notebook to a | radiator, though. | bbarnett wrote: | _Guy 's getting lightly electrocuted..._ | | A new initiative, to boost productivity, from management! | MertsA wrote: | That's due to a class-Y capacitor in the PSU used for EMI | filtering. Honestly it's harmless and you'll even see this | issue on a MBP if you don't use the three prong cord that has a | ground. Normally it's so slight that you don't feel it but if | you lightly rub your finger over the chassis you can sort of | feel a texture to the surface that's not actually there. It's | 60Hz but it feels like ridges on the surface and it disappears | if you unplug it or plug it in using a grounded cord. | | https://www.allaboutcircuits.com/technical-articles/safety-c... | rolandog wrote: | I've felt that faux-texture phenomenon if I rub a finger on | the stainless-steel surface of the dishwasher's door in the | apartment I'm currently renting (living in a ~50-year-old | flat I'm the Netherlands, though the dishwasher is almost | brand-new). Would a similar cause of lack of grounding be at | play here? | everybodyknows wrote: | Until you get that looked into, I'd take extra care not to | simultaneously touch the door with one hand and any | possibly solid ground e.g. water pipe with the other. | benj111 wrote: | I'm confused by this. My laptop jack's have 2 pins + and -. No | earth. I've taken apart power bricks, and they aren't wired to | earth either, So how (on earth) would earth be impacting the | laptop? | | Plus if the lack of earth is showing as a problem, that suggests | an issue elsewhere as all being well earth shouldn't be getting | used. | dima_vm wrote: | Frame.work laptops have properly grounded charger (over UBC-C). | jaclaz wrote: | That (at least in EU) is a Class II insulated device (as most | low power chapters/adapters): | | https://en.wikipedia.org/wiki/Appliance_classes#Class_II | | But I have seen laptop chargers with earth/ground, I guess it | depends. | | From the overall description it seems to me more likely that | for _some reasons_ only indirectly connected to the poor | grounding the AC unit introduced some kind of spurious (or | stray) voltage on the neutral. | | https://en.wikipedia.org/wiki/Stray_voltage | masklinn wrote: | > But I have seen laptop chargers with earth/ground, I guess | it depends. | | All the mac chargers I've had had a grounding pin. | | Whether they're actually grounded depends whether you're | using the wall-wart adapter or the cable: in europe at least | the cable has a grounded plug, the wall wart is just a | europlug. | lucumo wrote: | > All the mac chargers I've had had a grounding pin. | | The MBPs I've had only came with an USB-C charger. Those | come with a Europlug, which doesn't have an earth | connector. | masklinn wrote: | > The MBPs I've had only came with an USB-C charger. | | That's not exclusive, USB-C has ground pins. | | > Those come with a Europlug, which doesn't have an earth | connector. | | Yes, but if you remove the europlug you should see that | the charger has a metallic nub onto which the adapter | clips. The 140W charger has one at least, and so did the | old 85W chargers. Non-earthed chargers (e.g. iphone | chargers) have a plastic nub instead. | | As I wrote the europlug adapter is not earthed, but the | cables (with a CEE 7/7 or whatever the standard is in | your country) are earthed. I'd assume the UK wall wart | adapter is also earthed but I've never seen one. | | You can see the earthing on the charger side of the | cable, because it has two metallic strips inside the | recesses, to connect to the nub. | david_allison wrote: | > I'd assume the UK wall wart adapter is also earthed but | I've never seen one. | | https://i.imgur.com/X6uxKaq.png - UK MacBook Pro M1 wall | wart | masklinn wrote: | There's a metallic ground pin but that doesn't | necessarily mean much, I've got an iphone adapter (from | the world kit) which is the same and is ungrounded | (because the old switchable power adapter has no ground | nub). | | You need to check the back of the plug, the nub of the | charger (which is metallic) slides into a rail thing. | With the cables, the rails have a metal strip to connect | with the charger's nub: https://discussions.apple.com/con | tent/attachment/8ec896d8-54... | lucumo wrote: | > That's not exclusive, USB-C has ground pins. | | That's a circuit ground, not an earth ground. It's not | for connecting the device to an earth pin. | | > if you remove the europlug you should see that the | charger has a metallic nub onto which the adapter clips. | | I see. I looked at mine, a 61W adapter. Interesting that | they chose to use a C7/C8 connection with a separate | metallic nub, instead of a C5/C6 Mickey Mouse connection. | heinrich5991 wrote: | I actually measured that Dell USB-C chargers forward | grounding to the outside metal of the USB-C plug, and the | laptop actually uses that grounding for its chassis. | ilyt wrote: | Could be grounded via USB ground on AC-connected USB hub, or | monitor. | bmicraft wrote: | The only way this makes sense is, if his neutral wire wasn't at | 0V either (which can happen when pulling a lot of current from | insufficiently thick wire) | polygot wrote: | Wow, I did not expect this to hit the front page. | | Lots of excellent questions. If you'd like to get notified when I | write an extended version of this post with more details, sign up | to my mailing list here: http://eepurl.com/idzoGv | dewyatt wrote: | > To rule out if it was a coding error, I tried to decompress the | gzip file with bash via gzip -dc file. bash threw a strange | error, "can't seek file descriptor" when trying to read the file. | This error is emitted from bash.c here. | | Unless I am reading this wrong, the error would have been emitted | by gzip, not bash. There is no redirection or anything here, bash | is not even aware of that file. | severino wrote: | I remember many years ago I had a computer where, sometimes, | programs crashed when trying to launch them. They segfaulted for | no apparent reason. If I rebooted the computer, they may work. It | usually happened with big programs like Firefox, Thunderbird, | etc. I once noticed that I didn't had to reboot the computer to | make them work: just emptying the caches | (/proc/sys/vm/drop_caches). In fact, the md5sum of the binaries | giving troubles, before and after emptying the caches, were | different: one random byte had a different value. I never knew | what caused the problems, I always thought it was either an | unsupported device or a faulty component, however things like | memtest never reported any issue. | | When I got a new computer and was about to dispose that one | (finally!) somebody told me it could be related to electricity | problems. I then had that computer plugged to a different outlet | during its last week and, apparently, I got no issues; however, | issues didn't always happen, so I never knew if that was the | cause or not. | xattt wrote: | Grounding to the water heater? Isn't acceptable practice to bond | the ground wire to the cold water pipe? | adrianmonk wrote: | Perhaps it is, but it's the cold water pipe which connects to | the water heater, and they either slightly misunderstood or | didn't want to explain in detail. | jbverschoor wrote: | With all the plastic pipes these days? | MonkeyMalarky wrote: | That would be not-so-fun surprise when doing a renovation. I | know lots of DIYers who like to cut out the copper segments | and redo with plastic since it's easier to work with. | jbverschoor wrote: | DIY? The whole industry uses it and many cities use plastic | pipes to deliver water as well. Simply put, you're not | supposed to use water pipes for ground. That was done many | years ago (prior to 1980 here). | MertsA wrote: | This has killed a few plumbers before. Not due to using it | as a ground which is honestly completely safe but due to a | faulty water heater that was inadvertently using the copper | pipe as the neutral. The plumber turns off the water and | cuts the pipe, then grabs both ends and pulls them apart | and now he's got wet hands on both sides of the circuit he | just cut. | hulitu wrote: | May be accepted by some people but it carries a risk of | electrocution. | dugmartin wrote: | Plumbing (at least here in Massachusetts, maybe it's national | code?) is usually grounded back to the panel which also grounds | to external driven ground rods. I believe that is in case the | plumbing is accidentally energized due to a loose wire it has a | route to ground. | ninefathom wrote: | A developer is surprised that improper electrical infrastructure | causes systemic computer malfunctions. Surprised enough to write | an article about it. | | I feel like this just perfectly summarizes my early years in the | tech field, back when I was a screwdriver jockey and spent my | afternoons diving under desks. "Why yes, person who gets paid | more than twice what I do- spilling a chai latte on your laptop | keyboard does mean that it has to go away to a computer hospital | for a bit, and no, I cannot magically go back in time and make a | copy of all of your important files on an external hard drive for | you." | | To the author: no hard feelings- I love devs. But just like you | might be surprised at the person struggling to write a simple be | five-line bash script, sometimes the hardware-oriented folks are | surprised at what doesn't occur as an obvious issue to others. | dehrmann wrote: | What's surprising is how subtle the failure started. ___________________________________________________________________ (page generated 2022-11-12 23:00 UTC)