[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.
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