7 ms·

I think when it comes to safety restrictions should be there. The hacker in me hates it too but just imagine if a small portion of standard-looking outlets did

I think when it comes to safety restrictions should be there. The hacker in me hates it too but just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. Many applicances would break, or perhaps even catch fire. If there were many different USB-A devices and people were used to checking the voltage output before plugging, that might not be needed, but since probably none of us check for a USB-A port to see if it outputs 7.5V, it better be mandatory to be certified. Though, maybe it is, but still those cheap Chinese adapters slip away.

nicolaslem 3y ago
From my experience appliances tolerate a wide range of voltages. The outlets in my house routinely deviate from the standard 230V, with the lowest I have seen at 170V and highest at about 260V. I have not had any appliance malfunction. Edit: I am not advising anyone to deliberately do stupid things, simply mentioning that from my experience the builtin margin is fairly large.
- justsomehnguy 3y ago
  Anything with an AC/DC transformation would be fine, anything with an AC motor would be not. Partially, not the every compressor in a refrigerator would tolerate that. But 170V... yikes!
- bayindirh 3y ago
  Most of them are either 110-240V appliances, or lose performance when it goes around 170, and you may not notice. 260V is in +/- 10% threshold and is possibly falls within "engineered in tolerance" range, but will probably shorten the life of many appliances if supplied constantly.
- etimberg 3y ago
  Are you measuring RMS voltage or just the instantaneous voltage? An RMS voltage of 230V corresponds with a peak voltage of ~325V so reading of 260V could theoretically happen.
  - nicolaslem 3y ago
    That's the reading from my UPS, I believe it's RMS since it reads 234 V currently.
  - mike50 3y ago
    That's not how it works. For a sine wave the integral converts to Vpeak/Sqrt(2)
- lxgr 3y ago
  You (or your landlord) should probably hire an electrician to get that checked out – especially the higher voltage might be indicative of some scarier failure modes. A voltage drop of 25% could also mean you have semi-broken wiring somewhere, which can cause fires or shock hazards on faulty appliances.
  - nicolaslem 3y ago
    I did but unfortunately it quickly turned into all parties involved blaming each other (it's your utility, it's your installation...) and it got nowhere. For the past year it's been much more stable than before so I don't worry too much about it.
    - smallpipe 3y ago
      Make sure you have good insurance and multiple loud smoke detectors...
      - ajb 3y ago
        Insurance won't cover if you knew there was a fault and didn't fix it!
        repiret 3y ago
        Do you have a citation for that?
        ajb 3y ago
        Sure. This is the relevant clause in my current home insurance policy: "You must take steps to maintain the Home in a good state of repair and take all reasonable precautions to avoid loss, damage or injury and to safeguard all property insured from loss or damage." These things are pretty standard - I would be very surprised if there isn't a similar clause in all of them. Which implies that, if you fail to do so, they don't have to pay up. The wording in your policy may be different. What are "reasonable steps" will depend on legal precedent. It may, for example, take into account that you're not an expert, and will probably include some reasonable time to get stuff fixed. But certainly it provides them the opportunity to deny a claim. Obligatory disclaimer: I am not a lawyer or insurance expert, get your own advice if you need it.
- zebracanevra 3y ago
  Thats quite a spread. Is it up to spec where you are?. In Australia we have 230V nominal, but the allowed range is from 216 (-6%) to 254 (+10%).
- ajb 3y ago
  Lots of devices have switched mode power supplies that will still output the same voltage. Last time I had a brownout the only thing that stopped working was the washing machine, and I thought that was broken. Paradoxically, it may be the lower voltages that are more dangerous, because it will result in a higher current draw from all the devices. Mains voltage has a nontrivial allowed range (in fact in Europe they increased it slightly so that devices would work across countries with slightly different original standards) but this is well out of spec.
cesarb 3y ago
> just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. We have something like that here in Brazil. On cities which use 127V as the standard voltage (some cities use 220V), you can get 220V by using a pair of phases instead of a phase and the neutral, and it's common to find a few standard-looking sockets which are 220V instead of 127V. They might be colored red, they might have a yellow sticker saying "220V" next to it, or they might be completely unmarked. If your device is 127V only, or it has a manual 127V/220V switch which is on the 127V position, and you plug it into one of these 220V sockets, it will be damaged. (The standard we use for consumer AC power plugs and sockets, NBR 14136, does not make a distinction between voltages; the same plugs and sockets are used for both 127V and 220V.)
- _3u10 3y ago
  Plus there’s 240V in Paraguay. I travel with cheap universal adapters and never have any problems.
- stephen_g 3y ago
  That sounds incredibly error prone and actually quite dangerous! At least a lot of AC to DC converters are universal voltage and frequency, but not all appliances! In Australia we have only one voltage that will ever come out of a single phase socket, but the standards took the opposite approach with current ratings - the sockets are cleverly designed in terms of their current capacity so (assuming it’s been installed correctly) you can’t make mistakes without illegal and dangerous modifications. In the standard socket, you can have 10 amp, 15 amp or 20 amp, and they all have different sized pins. For the 15 amp plug and socket, the ground pin is larger, so a 15 amp plug cannot fit into a 10 amp socket. A 20 amp plug has all three pins larger, so it doesn’t fit in a 10 amp or 15 amp socket. But a 10 amp plug can still fit and sit snugly in a 15 or 20 amp socket, and a 15 amp can still fit into a 20 amp socket with no problems. It’s pretty clever. For bigger stuff, or anything three-phase, you then have big industrial circular ones, which I think have a similar system to not let you plug a higher current device into a socket that can’t supply enough current. I believe there are also three phase plugs and sockets both with neutral and without neutral, and if the plug has a neutral pin it doesn’t fit into a socket that doesn’t supply neutral.
kayfox 3y ago
> just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. Every once and a while an electrician wires up standard US outlets to 480v 3-phase instead of 208v 3-phase, so you end up with an outlet designed for 120v that puts out 277v. Sometimes noone notices because the switching power supplies plugged into them are just fine with this.
baq 3y ago
> The hacker in me hates it too but just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. Overvoltage is now routine in places where there's lots of PV installed in homes and not enough load nearby. If you live in such a place, you have a deep appreciation of varistors and should have either good insurance or a little bit of soldering skills... preferably both.
- xenadu02 3y ago
  > Overvoltage is now routine in places where there's lots of PV installed in homes and not enough load nearby. Every solar inverter / microinverter manufactured in the past two decades (if not older) must monitor the grid voltage+frequency and disconnect if it falls outside of a certain tolerance. If things go out of tolerance there is a defined period of time where it must recover or the inverter is required to trip out. There are also hard safety limits that cannot be exceeded whatsoever. I am not aware of any conditions that would result in overvoltage. In CA as of (IIRC) 2021 these systems must be hooked up to some kind of online monitoring so the utility can temporarily command them to exceed tolerances. If the grid is going unstable due to load the last thing you want is everyone's PV system tripping off making the supply situation worse. So the utility can inform the system to exceed the normally tight tolerances by a larger deviation. They can also command PVs systems to shut off but there are strict limits on how often and how long they can do that and it must be driven by grid stability needs.
  - baq 3y ago
    Yes, absolutely, same here. The problem is varistors blow out before the safety measures work. Perhaps due to wear or low quality, but this still happens.
    - xenadu02 3y ago
      I'm not sure how a single inverter failure could drive voltage high. Or how a varistor failure could cause a problem... The inverter has to perform a DC-AC conversion and has many more ways to fail safe than unsafe but I'm not saying it is impossible. I've seen some oddball things. But it certainly isn't a widespread issue. Smart meters report voltage, the utilities would know if this was happening and given how much they hate rooftop solar they'd be yelling about it if they could.

nicolaslem 3y ago

From my experience appliances tolerate a wide range of voltages. The outlets in my house routinely deviate from the standard 230V, with the lowest I have seen at 170V and highest at about 260V. I have not had any appliance malfunction. Edit: I am not advising anyone to deliberately do stupid things, simply mentioning that from my experience the builtin margin is fairly large.

justsomehnguy 3y ago
Anything with an AC/DC transformation would be fine, anything with an AC motor would be not. Partially, not the every compressor in a refrigerator would tolerate that. But 170V... yikes!
bayindirh 3y ago
Most of them are either 110-240V appliances, or lose performance when it goes around 170, and you may not notice. 260V is in +/- 10% threshold and is possibly falls within "engineered in tolerance" range, but will probably shorten the life of many appliances if supplied constantly.
etimberg 3y ago
Are you measuring RMS voltage or just the instantaneous voltage? An RMS voltage of 230V corresponds with a peak voltage of ~325V so reading of 260V could theoretically happen.
- nicolaslem 3y ago
  That's the reading from my UPS, I believe it's RMS since it reads 234 V currently.
- mike50 3y ago
  That's not how it works. For a sine wave the integral converts to Vpeak/Sqrt(2)
lxgr 3y ago
You (or your landlord) should probably hire an electrician to get that checked out – especially the higher voltage might be indicative of some scarier failure modes. A voltage drop of 25% could also mean you have semi-broken wiring somewhere, which can cause fires or shock hazards on faulty appliances.
- nicolaslem 3y ago
  I did but unfortunately it quickly turned into all parties involved blaming each other (it's your utility, it's your installation...) and it got nowhere. For the past year it's been much more stable than before so I don't worry too much about it.
  - smallpipe 3y ago
    Make sure you have good insurance and multiple loud smoke detectors...
    - ajb 3y ago
      Insurance won't cover if you knew there was a fault and didn't fix it!
      - repiret 3y ago
        Do you have a citation for that?
        ajb 3y ago
        Sure. This is the relevant clause in my current home insurance policy: "You must take steps to maintain the Home in a good state of repair and take all reasonable precautions to avoid loss, damage or injury and to safeguard all property insured from loss or damage." These things are pretty standard - I would be very surprised if there isn't a similar clause in all of them. Which implies that, if you fail to do so, they don't have to pay up. The wording in your policy may be different. What are "reasonable steps" will depend on legal precedent. It may, for example, take into account that you're not an expert, and will probably include some reasonable time to get stuff fixed. But certainly it provides them the opportunity to deny a claim. Obligatory disclaimer: I am not a lawyer or insurance expert, get your own advice if you need it.
zebracanevra 3y ago
Thats quite a spread. Is it up to spec where you are?. In Australia we have 230V nominal, but the allowed range is from 216 (-6%) to 254 (+10%).
ajb 3y ago
Lots of devices have switched mode power supplies that will still output the same voltage. Last time I had a brownout the only thing that stopped working was the washing machine, and I thought that was broken. Paradoxically, it may be the lower voltages that are more dangerous, because it will result in a higher current draw from all the devices. Mains voltage has a nontrivial allowed range (in fact in Europe they increased it slightly so that devices would work across countries with slightly different original standards) but this is well out of spec.

cesarb 3y ago

> just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. We have something like that here in Brazil. On cities which use 127V as the standard voltage (some cities use 220V), you can get 220V by using a pair of phases instead of a phase and the neutral, and it's common to find a few standard-looking sockets which are 220V instead of 127V. They might be colored red, they might have a yellow sticker saying "220V" next to it, or they might be completely unmarked. If your device is 127V only, or it has a manual 127V/220V switch which is on the 127V position, and you plug it into one of these 220V sockets, it will be damaged. (The standard we use for consumer AC power plugs and sockets, NBR 14136, does not make a distinction between voltages; the same plugs and sockets are used for both 127V and 220V.)

_3u10 3y ago
Plus there’s 240V in Paraguay. I travel with cheap universal adapters and never have any problems.
stephen_g 3y ago
That sounds incredibly error prone and actually quite dangerous! At least a lot of AC to DC converters are universal voltage and frequency, but not all appliances! In Australia we have only one voltage that will ever come out of a single phase socket, but the standards took the opposite approach with current ratings - the sockets are cleverly designed in terms of their current capacity so (assuming it’s been installed correctly) you can’t make mistakes without illegal and dangerous modifications. In the standard socket, you can have 10 amp, 15 amp or 20 amp, and they all have different sized pins. For the 15 amp plug and socket, the ground pin is larger, so a 15 amp plug cannot fit into a 10 amp socket. A 20 amp plug has all three pins larger, so it doesn’t fit in a 10 amp or 15 amp socket. But a 10 amp plug can still fit and sit snugly in a 15 or 20 amp socket, and a 15 amp can still fit into a 20 amp socket with no problems. It’s pretty clever. For bigger stuff, or anything three-phase, you then have big industrial circular ones, which I think have a similar system to not let you plug a higher current device into a socket that can’t supply enough current. I believe there are also three phase plugs and sockets both with neutral and without neutral, and if the plug has a neutral pin it doesn’t fit into a socket that doesn’t supply neutral.

kayfox 3y ago

> just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. Every once and a while an electrician wires up standard US outlets to 480v 3-phase instead of 208v 3-phase, so you end up with an outlet designed for 120v that puts out 277v. Sometimes noone notices because the switching power supplies plugged into them are just fine with this.

baq 3y ago

> The hacker in me hates it too but just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. Overvoltage is now routine in places where there's lots of PV installed in homes and not enough load nearby. If you live in such a place, you have a deep appreciation of varistors and should have either good insurance or a little bit of soldering skills... preferably both.

xenadu02 3y ago
> Overvoltage is now routine in places where there's lots of PV installed in homes and not enough load nearby. Every solar inverter / microinverter manufactured in the past two decades (if not older) must monitor the grid voltage+frequency and disconnect if it falls outside of a certain tolerance. If things go out of tolerance there is a defined period of time where it must recover or the inverter is required to trip out. There are also hard safety limits that cannot be exceeded whatsoever. I am not aware of any conditions that would result in overvoltage. In CA as of (IIRC) 2021 these systems must be hooked up to some kind of online monitoring so the utility can temporarily command them to exceed tolerances. If the grid is going unstable due to load the last thing you want is everyone's PV system tripping off making the supply situation worse. So the utility can inform the system to exceed the normally tight tolerances by a larger deviation. They can also command PVs systems to shut off but there are strict limits on how often and how long they can do that and it must be driven by grid stability needs.
- baq 3y ago
  Yes, absolutely, same here. The problem is varistors blow out before the safety measures work. Perhaps due to wear or low quality, but this still happens.
  - xenadu02 3y ago
    I'm not sure how a single inverter failure could drive voltage high. Or how a varistor failure could cause a problem... The inverter has to perform a DC-AC conversion and has many more ways to fail safe than unsafe but I'm not saying it is impossible. I've seen some oddball things. But it certainly isn't a widespread issue. Smart meters report voltage, the utilities would know if this was happening and given how much they hate rooftop solar they'd be yelling about it if they could.