4 ms·

> 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 her

by 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.
- cesarb 3y ago
  > In the standard socket, you can have 10 amp, 15 amp or 20 amp, and they all have different sized pins. Yeah, Brazilian NBR 14136 does that too. It has 10A and 20A variants, and the only difference is that 20A has slightly larger pins, so it won't fit into a 10A socket. (And the international standard it was based on, IEC 60906-1, has only a 16A variant with an intermediate pin size, so the 10A plug would fit into its socket and its plug would fit into the 20A socket.) Annoyingly, that's the only difference, making it quite hard to tell just by looking whether it's a 10A or 20A plug/socket; you have to try and see if it fits.
- terom 3y ago
  > 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. That sound dangerous. The larger fuse sized for the 20A socket will not protect the smaller conductors in the cable sized for the 10A plug, they can get overloaded. The three-phase / industrial CEE plugs and sockets used in the EU are sized for 16A/32A/63A/125A. It's perfectly legal and safe to make a passive adapter that lets you plug a 32A appliance or distribution box into a 16A socket, you just can't load it higher than the 16A fuses on the socket. Going the other way around (16A plug into a 32A socket) you MUST have a circuit breaker in between to provide the required overload protection.
  - Tyrannosaur 3y ago
    That doesn't make sense though. The fuses aren't to protect the load; they are to protect the circuit. It's up to whatever device you are plugging in to not draw more current than it can handle. If I have a 3 Watt doohickey, I don't go looking around to find a 0.025A socket, I plug it in to my 15A wall socket and everything works great.
    - terom 3y ago
      Yeah, the risks mainly come with extension cords, like plugging a bunch of 10A appliances into a single 20A outlet via a 10A rated extension cord with multiple 10A outlets. Appliances themselves with their own input fuses and captive cables are less risky, although some kind of internal wiring short could still get all melty. It's true that sizing the plugs that way does prevent you from plugging a 20A appliance into a 10A extension cord, which makes sense.
marcosdumay 3y ago
Yeah, the wiring code says the 220V outlets on 110V areas must be red. Marking is optional. But I've actually have never seen a red one.
- FireBeyond 3y ago
  That's odd, because in a lot of contexts (hospitals, EMS, etc.), red outlets are used to denote outlets that are connected to battery/UPS, i.e. critical loads, versus the regular, which can be 'sacrificed' in an outage.
mcronce 3y ago
In my old house (US) there was an outlet that was setup that way. Two phases plus ground on a bog standard looking 120V outlet. Made the discovery when we plugged a 500W work light into it while renovating and it exploded after a few minutes.
- gabrielhidasy 3y ago
  So you had a glorious 2kW work light for a few minutes.
  - mcronce 3y ago
    "The candle that burns twice as bright, burns half as long" The math was a little off, but the quote still comes to mind

by cesarb 3y ago

_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.

cesarb 3y ago
> In the standard socket, you can have 10 amp, 15 amp or 20 amp, and they all have different sized pins. Yeah, Brazilian NBR 14136 does that too. It has 10A and 20A variants, and the only difference is that 20A has slightly larger pins, so it won't fit into a 10A socket. (And the international standard it was based on, IEC 60906-1, has only a 16A variant with an intermediate pin size, so the 10A plug would fit into its socket and its plug would fit into the 20A socket.) Annoyingly, that's the only difference, making it quite hard to tell just by looking whether it's a 10A or 20A plug/socket; you have to try and see if it fits.
terom 3y ago
> 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. That sound dangerous. The larger fuse sized for the 20A socket will not protect the smaller conductors in the cable sized for the 10A plug, they can get overloaded. The three-phase / industrial CEE plugs and sockets used in the EU are sized for 16A/32A/63A/125A. It's perfectly legal and safe to make a passive adapter that lets you plug a 32A appliance or distribution box into a 16A socket, you just can't load it higher than the 16A fuses on the socket. Going the other way around (16A plug into a 32A socket) you MUST have a circuit breaker in between to provide the required overload protection.
- Tyrannosaur 3y ago
  That doesn't make sense though. The fuses aren't to protect the load; they are to protect the circuit. It's up to whatever device you are plugging in to not draw more current than it can handle. If I have a 3 Watt doohickey, I don't go looking around to find a 0.025A socket, I plug it in to my 15A wall socket and everything works great.
  - terom 3y ago
    Yeah, the risks mainly come with extension cords, like plugging a bunch of 10A appliances into a single 20A outlet via a 10A rated extension cord with multiple 10A outlets. Appliances themselves with their own input fuses and captive cables are less risky, although some kind of internal wiring short could still get all melty. It's true that sizing the plugs that way does prevent you from plugging a 20A appliance into a 10A extension cord, which makes sense.

marcosdumay 3y ago

Yeah, the wiring code says the 220V outlets on 110V areas must be red. Marking is optional. But I've actually have never seen a red one.

FireBeyond 3y ago
That's odd, because in a lot of contexts (hospitals, EMS, etc.), red outlets are used to denote outlets that are connected to battery/UPS, i.e. critical loads, versus the regular, which can be 'sacrificed' in an outage.

mcronce 3y ago

In my old house (US) there was an outlet that was setup that way. Two phases plus ground on a bog standard looking 120V outlet. Made the discovery when we plugged a 500W work light into it while renovating and it exploded after a few minutes.

gabrielhidasy 3y ago
So you had a glorious 2kW work light for a few minutes.
- mcronce 3y ago
  "The candle that burns twice as bright, burns half as long" The math was a little off, but the quote still comes to mind