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> 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.

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I suspect both; I mean who worries about gzip when their touchpad is 'spicy'!

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.

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.

I thought one of the two wires should be equal to ground?

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.

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?

>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...

At dc for sure, at 60hz perhaps imaginary impedance could create "spicy case". I only thought about it because I used to use a welding cable adapter for my dryer port that had a "bootleg ground" and the internet warned me a shock from the case could be a result.

Why would it kill people?

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.

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.

I think some AC to DC transformers bond the AC neutral and the DC negative.

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.

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.

If the voltage was high enough to be dangerous, would a foam mic cover protect you?

First of all, it's not just the voltage that is dangerous. Though, higher voltage means the arc is more probable, of course. A foam cover is a poor insulator, but at least it helps keeping the minimal distance from the conductive microphone grill. In this case we're talking mostly about avoiding unpleasant shocks, not some life-endangering situations.

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...

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

Definitely still occurred on my 2017 macbook pro.

Still occurs with my 2021 M1 MBP

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.

I paid attention a little and there is a spark when i plug the laptop charger in. 2018 mbpro. With the short plug in the charger, not the long power cord.

No other symptoms though.

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.)

Try aftermarket? https://smile.amazon.com/Grounded-Duckhead-Apple-Mac-Adapter...

Shouldn't be able to hurt you THAT much ...

> 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.

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.

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.

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.

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.

> 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.

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.

Old copper water pipes, yes. Obviously you can’t ground using a PEX pipe.

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.

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.

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.

I think part of his worry was lightning strike busting their equipment. Unsure about the rest.

> 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.

I think the continuous water still maintains a ground path even in pex

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.

Pipe is a great ground, if done properly. Nice big hunk of metal thoroughly embedded into the ground is all a ground plate is.

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.

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.

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).

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.

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.

I expect it's the landlord instructing the electrician to do a half-assed job to keep the cost down.

Except multiple visits are expensive, and no one wants the place to burn down.

Some old house, wired not understanding ac, mixed up the return and ground. Stuff works, but...

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.

Probably talking about a window unit there.

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.

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.

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"

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.

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).

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.

> I highly, highly recommend you read up on electrical theory.

Do you have any suggestions on books, tutorials or similar?

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.

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.

Similarly arc fault detectors try to detect arc faults which a GFCI won’t “see”.

Indeed - and an electric chair will kill even if it is both properly grounded and plugged into a GFCI socket capable of handling the current (aside: do electric chairs have UL certification? I doubt it, but the states in which it is still nominally an option presumably want the operators to be safe.)

If you are put / put yourself into the normal current path (such as while working on the innards of plugged-in and switched-on equipment), you are just the load (or part of it), and neither GFCI nor previous protection schemes will help you.

> 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.

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.

It's not just a spicy track pad, it's monitor issues and (the whole premise of the post) data corruption issues

My apologies: I completely agree that there was definitely something wrong with OP's situation. I misunderstood your response, and thought you were objecting to KMnO4's claim that you can have a safe two-wire (no ground wire) scenario if you use GFCI.

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