The most pointless ISO standard I've encountered
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@LaoC Okay, so if I understand correctly, the whole polarisation thing is all about safety when dealing with the plugs and wiring. I could technically stick a pair of wires into the wall and connect them to the opposite pins on my devices?
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@kazitor said in The most pointless ISO standard I've encountered:
@LaoC Okay, so if I understand correctly, the whole polarisation thing is all about safety when dealing with the plugs and wiring. I could technically stick a pair of wires into the wall and connect them to the opposite pins on my devices?
For most devices, yes. I believe the words "double insulation" are also indicative this is true for that device (the symbol is a box inside another box, I think?)
For things where "ground" can be contacted by external things, yes, but potential danger is increased.
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As @cabrito said, in properly designed equipment, polarization matters for two things:
- fuses. If the polarization is wrong, the fuse will not protect against live-to-earth short circuits.
- switches. If only one wire is switched and the polarity is wrong, you'll end up with something that appears to be switched off, but still has live voltage inside.
If your electrical installation includes a RCD/GFCI (as it should), neither is a real problem, since it will cut the power in both cases before anything dangerous happens. And in practice, even in countries where plugs are polarized, it's not rare to find outlets that have live and neutral reversed.
Otherwise, reversing the polarization is a bad idea.
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@Zerosquare Think I have a much clearer idea now.
Polarised means it's easier to design equipment dealing with the power supply as there's a pre-determined standard for which is live.
Non-polarised means it's easier to plug things in, but you have to take care with which wire is live during electrical installation.
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@Tsaukpaetra said in The most pointless ISO standard I've encountered:
@acrow said in The most pointless ISO standard I've encountered:
But to do that, I'll have to either write a new font converter or write a parser for the currently used library's (D4D) font-generator output. So, it's not over yet after all. You just extended my misery by another 2-3 years that this garbage can spend on the market before we HAVE to replace the hardware with something better. Thanks a lot.
I heard there were chips that generate fonts for you. Maybe you could slap one of those instead of using a library?
I could. IFF I can get it verified that JIS0208 includes all the kanji that we may care about, ever. Since this is for an industrial application, the $1.50 for an ER3300-1 is not unpalatable.
On the other hand, a 16MBit FLASH IC is $0.38, and 32MBit is $0.60, not including pick-and-place and other overhead. I can get all of the logging and storage space benefits, not have to worry about the limitations of the font-set in the chip, plus have a fairly predictable expiry date to boot. And if we play our cards right, we can offload the translation work to resellers.
But none of these help me right now, since the current hardware is already in manufacturing, and will not be changed, unless there is an obstacle to sales that cannot be solved via software.
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@Zerosquare said in The most pointless ISO standard I've encountered:
it's not rare to find outlets that have live and neutral reversed.
Also not rare to find PE connected to Live voltage.
You see, old buildings get upgraded to newer sockets with Protective-Earth. But the cabling only has 2 wires. So they connect PE to Neutral to achieve the same effect. Except sometimes the electrician messes up. This is usually noticed after a non-double-isolated device with a metallic chassis gets connected to the socket in question, killing someone.
No, really; the machine works just the same, whether you connect PE to Live or Neutral. You only notice the difference with either a residual-current device or by shorting the chassis to ground through your body.
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@kazitor said in The most pointless ISO standard I've encountered:
@Zerosquare Think I have a much clearer idea now.
Polarised means it's easier to design equipment dealing with the power supply as there's a pre-determined standard for which is live.
Depends what standard you're designing for. If it's the EU one you really don't have to care. It would really matter only if someone started to take the appliance apart while it was still plugged in. Assuming you have a proper breaker in your house, GFCI isn't essential.
Non-polarised means it's easier to plug things in, but you have to take care with which wire is live during electrical installation.
Not really, as there's a 50/50 chance which way the plug will end up in the socket anyway so you can't plan for that. With polarized you have to take care because you really don't want a device that is designed so it's only safe with a particular live wire to end up having the other one live.
@acrow said in The most pointless ISO standard I've encountered:
You see, old buildings get upgraded to newer sockets with Protective-Earth. But the cabling only has 2 wires. So they connect PE to Neutral to achieve the same effect. Except sometimes the electrician messes up. This is usually noticed after a non-double-isolated device with a metallic chassis gets connected to the socket in question, killing someone.
Holy fuck. OK, I've seen some messed up installation but luckily I've been spared this type.
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@acrow said in The most pointless ISO standard I've encountered:
You see, old buildings get upgraded to newer sockets with Protective-Earth. But the cabling only has 2 wires. So they connect PE to Neutral to achieve the same effect. Except sometimes the electrician messes up. This is usually noticed after a non-double-isolated device with a metallic chassis gets connected to the socket in question, killing someone.
I wonder if this might be the reason for the
I found when redoing the electricity in my bathroom recently. I took the opportunity to tidy up some of the cabling behind the wall (the circuit that goes to the bathroom goes through a bedroom first) and ended up with a Earth wire that wasn't plugged. Upon connecting it to the rest of the Earth circuit, the fuse kept blowing when I put it back on, because that Earth wire was actually connected to a live wire at the other end.After much head-scratching, I just unplugged the wire from both ends and let it sit there unused (it's not actually needed for the rest of the circuit, I just thought that since it was there it would be nicer to have it plugged properly), but maybe something like what you describe happened at one point. Wires are colour-coded but some of them are older and the colours aren't the current ones and aren't always rigorously used, which might explain the confusion... (and also, the last electrician who touched this installation was very bad, so I wouldn't put it past him to have messed that up and never bothered to actually check)
If that's really what happened, I'm very glad that stuff plugged in this room is only basic stuff (lamps and alarm clocks) that don't have an earth plug...
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@remi said in The most pointless ISO standard I've encountered:
If that's really what happened, I'm very glad that stuff plugged in this room is only basic stuff (lamps and alarm clocks) that don't have an earth plug...
The bathroom in particular would be one place where I'd really want a working (and NOT wired to live!) protective earth, what with all the water around.
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@ixvedeusi Yes, which is why I was careful to make sure all wires end up where they should.
Although I still have a nagging doubt: all the old fixtures in the bathroom (sink, bathtub, radiator...) had an earth wire. I know this can be done for two reasons: either to ground metallic sinks so you don't get a nasty shock from time to time, or the other way round, to use the metal pipework as an earth conduit and therefore ground the rest of the circuit through them (that's probably totally forbidden in modern standards, but 50 years ago that did happen...).
Now that I've got brand new fixtures and PVC pipework, that second option is no longer possible (neither is the first one but that's less of an issue normally). And I haven't yet conclusively tracked down the earth wires to see which of the two options was correct. I'm a bit suspicious of the earthing of a whole sub-section of my installation now...
(too bad an earth-tester is relatively expensive and not something most people have at home... I can't even find a DIY-rental store that has one...)
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@acrow said in The most pointless ISO standard I've encountered:
@Zerosquare said in The most pointless ISO standard I've encountered:
it's not rare to find outlets that have live and neutral reversed.
Also not rare to find PE connected to Live voltage.
You see, old buildings get upgraded to newer sockets with Protective-Earth. But the cabling only has 2 wires. So they connect PE to Neutral to achieve the same effect. Except sometimes the electrician messes up. This is usually noticed after a non-double-isolated device with a metallic chassis gets connected to the socket in question, killing someone.
No, really; the machine works just the same, whether you connect PE to Live or Neutral. You only notice the difference with either a residual-current device or by shorting the chassis to ground through your body.I would say the electrician messed up either way, because that's not the same effect at all.
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@remi said in The most pointless ISO standard I've encountered:
(too bad an earth-tester is relatively expensive and not something most people have at home... I can't even find a DIY-rental store that has one...)
I verified one PE connection by measuring it against a metallic radiator with a multimeter. Then measured the rest of them against that one. It's not 100% reliable, but...
If you have any un-paved ground under your window, you could strike in an eathing pike and measure the PEs against that.
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@JBert said in The most pointless ISO standard I've encountered:
that's not the same effect at all.
No, but it is apparently legal (in Finland).
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@acrow said in The most pointless ISO standard I've encountered:
@remi said in The most pointless ISO standard I've encountered:
(too bad an earth-tester is relatively expensive and not something most people have at home... I can't even find a DIY-rental store that has one...)
I verified one PE connection by measuring it against a metallic radiator with a multimeter. Then measured the rest of them against that one. It's not 100% reliable, but...
Actually, what I did was to run a wire (just a standard earthed extension) from a plug downstairs that I know is properly earthed, and checked whether it was connected to the earth of my plugs upstairs. But I got confusing results for some plugs, there was a connection, but a very poor one (whereas on other plugs the connection was very good, as expected).
Now I know that I get tri-phased current from the mains, and that my main electrical board has 3 rows, each one being powered by one of the phases from the mains (which I guess is the standard way to balance load across them). And while of course the earth doesn't come from the mains, in terms of cabling it does go through the same board(s). So I wonder if this poor connection that I see is not the result of the connection having to go through the boards, and the electronics of all the fuses and stuff causing trouble.
Or, the poor connection could be because the earth upstairs is still connected through e.g. one radiator and its pipework, and because that's not a very good earthing and of course the end point in the actual earth is far away from the main earthing point, then I get a poor connection.
So I'm not sure if my test shows that things are actually OK, or that things are actually broken (and of course I didn't think to test it before, so I can't compare to the initial state!).
If you have any un-paved ground under your window, you could strike in an eathing pike and measure the PEs against that.
I'll probably end up doing that, but I've got to get motivated enough to do it... getting a simple tester that you plug in and that tells you your earth value is much easier...
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@acrow said in The most pointless ISO standard I've encountered:
@JBert said in The most pointless ISO standard I've encountered:
that's not the same effect at all.
No, but it is apparently legal (in Finland).
This emoticon seems highly appropriate:
Now I only need an electrocuted variant...
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@acrow said in The most pointless ISO standard I've encountered:
If you have any un-paved ground under your window, you could strike in an eathing pike and measure the PEs against that.
It all depends whether you have TN or TT wiring. With TN (the normal modern configuration), testing voltage between some earthing rod and the PE wire doesn't really tell you much. There may be some low induced voltage, but that doesn't mean it's bad. What matters is the impedance of the whole loop, which you can measure by connecting a heavy load (eg a kettle) between L and PE. Any significant voltage appearing between PE and N means it's unsafe.
Of course if you have an RCD, it will trip, so to really measure anything you should first bypass it.Now a wtf:
When I moved in to the flat I live in currently, I discovered an ingenuous 'solution' by the former owner: Though the building has normal TN-C wiring, the PE pin in one socket was connected BOTH to the neutral wire in the same socket and to an iron water pipe. The meter had its current coil on the neutral wire (by mistake I guess, the seal looked genuine). So I tried an experiment and disconnected the neutral wire altogether and turned on the washing machine. Yep, it worked and the meter didn't even move. I don't know what exact percentage of energy he got for free through all these years, but definitely not zero.
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Gender sure is complicated.
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@LaoC Oh, sure, jump on the pedestal for recognizing a Female-Female while you erase their standard name. I for one can stand to call that a DB-36.
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@Gribnit: You can't assume anything just by looking. It may identify itself as a female DE-9, or as a USB-C plug.
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@sebastian-galczynski said in The most pointless ISO standard I've encountered:
@acrow said in The most pointless ISO standard I've encountered:
If you have any un-paved ground under your window, you could strike in an eathing pike and measure the PEs against that.
It all depends whether you have TN or TT wiring.
I did not find this page earlier, for once Wikipedia has a technical article with a lot of details that's still understandable (or maybe it's not that complicated... in any case, it's more readable than most stuff I found about that).
I'm not quite sure what is my situation. Modern regulations here apparently mandate that a home circuit should be TT but my installation is somewhat old so maybe that wasn't the case when it was built. OTOH, it was inspected a few years ago and the report didn't mention anything about this, so I'd be tempted to think that it follows modern standards and is TT.
With TN (the normal modern configuration), testing voltage between some earthing rod and the PE wire doesn't really tell you much. There may be some low induced voltage, but that doesn't mean it's bad.
If I'm indeed TT, then the earthing rod method should work (and of course it shouldn't trip anything). The only thing is that (I guess) the actual impedance I'll measure will depend on how far I put the earthing rod from the true earthing rod of the circuit, but I guess if I use the impedance from a known working earth plug as a reference, that should work.
But then it doesn't explain why my previous test gave an intermittent (=poor, but existing) connection between the earth plug and a known working earth plug (i.e. the earthing rod). Unless that circuit uses a different earthing rod, but that doesn't make much sense. That behaviour seems more consistent with a TN-C-S circuit where the separation happens after the switch board (so to close the earth between different sub-circuit it has to go through the breakers).
What matters is the impedance of the whole loop, which you can measure by connecting a heavy load (eg a kettle) between L and PE. Any significant voltage appearing between PE and N means it's unsafe.
Of course if you have an RCD, it will trip, so to really measure anything you should first bypass it.Yeah, that's the thing with these simple tests, you need to bypass the RCD to get them to work, which makes them not-so-simple to implement (I don't like at all the idea of fiddling with my electrical board!). AFAIUI, earth testing devices can do more or less the same thing, except with a small enough load (and therefore precise enough measurements) that it doesn't trip the RCD. But that's not something I can trivially emulate...
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@Gribnit said in The most pointless ISO standard I've encountered:
@LaoC Oh, sure, jump on the pedestal for recognizing a Female-Female while you erase their standard name. I for one can stand to call that a DB-36.
It was meant more as a silent protest against that toxic¹ 72-fold hypermasculinity.
¹ It's most likely not even RoHS compliant
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@Zerosquare SOAP was a real RFC.
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@remi said in The most pointless ISO standard I've encountered:
I'm not quite sure what is my situation. Modern regulations here apparently mandate that a home circuit should be TT
You're moving from TN to TT? Let me guess, it's in the US, right?
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@sebastian-galczynski No, France. And I have absolutely no idea what the standard really is, except that the French Wikipedia page (linked from the one mentioned earlier) says that TT is mandatory for home installations in France (and B*****m). And for all I know (i.e. not much), this might have been the case for as long as there was a regulation about this...
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@sebastian-galczynski said in The most pointless ISO standard I've encountered:
@remi said in The most pointless ISO standard I've encountered:
I'm not quite sure what is my situation. Modern regulations here apparently mandate that a home circuit should be TT
You're moving from TN to TT? Let me guess, it's in the US, right?
Probably just a social relabeling vs a real voltage potential dysphoria.
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That's really weird. Poland moves everything to TN, and TT is only seen in some small villages powered by an overhead line.
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@remi The Dutch one similarly mentions TT is standard, with earthing provided by the water mains in the past and by ground water nowadays.
My flat also has earthing originating from a steel rod which is >50cm away from the electricity mains, sitting right next to the natural gas mains.
RCDs (Dutch: aardlekschakelaar, lit: earth leakage switch) are very much obligatory.
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@acrow said in The most pointless ISO standard I've encountered:
strike in an eathing pike
I want to see someone killed with an earthing pike in an action movie, the witty rejoinder possibilities are awesome.
"And you had so much... potential", "Time to get down to earth", I mean, this stuff writes itself.
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@LaoC said in The most pointless ISO standard I've encountered:
@Gribnit said in The most pointless ISO standard I've encountered:
Gender sure is complicated.
gender changer
We have some of those at work and I’m totally lost at what they do. I can’t see both sides in your picture, so I assume it actually has two female sides.
We have a “gender changer” attached to a VGA cable that has two different sides, so it “changes” a male VGA cable to a male VGA.
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@topspin said in The most pointless ISO standard I've encountered:
We have a “gender changer” attached to a VGA cable that has two different sides, so it “changes” a male VGA cable to a male VGA.
Does it still work the same, if you remove it?
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@Gribnit said in The most pointless ISO standard I've encountered:
@topspin said in The most pointless ISO standard I've encountered:
We have a “gender changer” attached to a VGA cable that has two different sides, so it “changes” a male VGA cable to a male VGA.
Does it still work the same, if you remove it?
Yeah, I tried that. My only :tinfoil: explanation was that the embedded
ChineseNSA spying chip won’t work.
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@topspin Can you still effectively
HAZARDTEMPEST
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@Gribnit I don't know what that means.
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@topspin Maybe the useless dongle is manipulating the RF spectrum available from the monitor cord, is what I meant. Also it probably isn't.
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@Gribnit said in The most pointless ISO standard I've encountered:
@acrow said in The most pointless ISO standard I've encountered:
strike in an eathing pike
I want to see someone killed with an earthing pike in an action movie, the witty rejoinder possibilities are awesome.
"And you had so much... potential", "Time to get down to earth", I mean, this stuff writes itself.
Lines for for the next season of The Transformers!
P-channeling @Perverted_Vixen: "When I'm here, the TTs come out"
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@topspin said in The most pointless ISO standard I've encountered:
@LaoC said in The most pointless ISO standard I've encountered:
@Gribnit said in The most pointless ISO standard I've encountered:
Gender sure is complicated.
gender changer
We have some of those at work and I’m totally lost at what they do. I can’t see both sides in your picture, so I assume it actually has two female sides.
One use I can think of is that they allow you to extend a cable by plugging a second one into it. Another use would be for old and/or self-built devices where the connectors might not be standardised and it turns out the other type of plug needs to go into it.
We have a “gender changer” attached to a VGA cable that has two different sides, so it “changes” a male VGA cable to a male VGA.
“The signal’s too good, let’s stick something between the device and the cable to degrade it a bit!”
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@Applied-Mediocrity said in The most pointless ISO standard I've encountered:
@Carnage
Did you just assume my Schrödinger?Schrödinger's Trap: Is a trap a trap until they trap you?
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@LaoC said in The most pointless ISO standard I've encountered:
@Gribnit said in The most pointless ISO standard I've encountered:
Gender sure is complicated.
We always called those "gender benders"
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@dcon said in The most pointless ISO standard I've encountered:
@LaoC said in The most pointless ISO standard I've encountered:
@Gribnit said in The most pointless ISO standard I've encountered:
Gender sure is complicated.
We always called those "gender benders"
I really wanted to try to push for actual slurs to characterize them by, so that the above would be called a gay plug. Oh well. Take what you can get.
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@topspin said in The most pointless ISO standard I've encountered:
@LaoC said in The most pointless ISO standard I've encountered:
@Gribnit said in The most pointless ISO standard I've encountered:
Gender sure is complicated.
gender changer
We have some of those at work and I’m totally lost at what they do. I can’t see both sides in your picture, so I assume it actually has two female sides.
The one that's visible is male; I assume it's not totally useless so the other side should be male as well.
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@Gribnit said in The most pointless ISO standard I've encountered:
I really wanted to try to push for actual slurs to characterize them by, so that the above would be called a gay plug. Oh well. Take what you can get.
A male that plugs into two females at once?
I you really want NSFW names for it, "cock block" would do.
