5 ms·

Why are toasters better at 240V? Can’t you just pull more current if you’re only at 120V (or whatever it is in the US) and get the same power? I guess there’s

Why are toasters better at 240V? Can’t you just pull more current if you’re only at 120V (or whatever it is in the US) and get the same power? I guess there’s some internal resistance or something, but…

mypgovroom 2y ago
You have a 240v toaster?
- xanderlewis 2y ago
  Well, closer to 230.
  - qayxc 2y ago
    goes to check real quick between 238V and 245V at my outlets.
- stuaxo 2y ago
  Living in an a country with 240v mains, yep.
bbatha 2y ago
More current needs thicker wires. The average US outlet is wired for 120v15amp. 20 amp circuits are somewhat common, though 20amp receptacles are not. Certainly not enough for commodity appliances to rely on. Going to more than 20amp requires a multiphase circuit which are much more expensive and the plugs are unwieldy and not designed to be plugged and unplugged frequently.
- quickthrowman 2y ago
  > Going to more than 20amp requires a multiphase circuit There is no multi-phase power available in the vast majority of US houses. A typical residence has a 120/240 split-phase service, which is single-phase only. A service drop is two hot conductors from two of the three transformer phases and a center-tapped (between the two hot legs) neutral conductor. Either hot leg is 120v to ground and line to line is 240V. > https://en.m.wikipedia.org/wiki/Split-phase_electric_power https://en.m.wikipedia.org/wiki/Split-phase_electric_power Single-phase breakers are also available in sizes larger than 20A, usually all the way up to 125A.
generallee5686 2y ago
Having more current running through a wire means thicker wires. Higher voltage means less current to achieve the same power, so thinner wires for the same power. The tradeoff for higher voltage is it's more dangerous (higher chance of arcing etc).
wongarsu 2y ago
Houses are wired for 16A per circuit on both sides of the pond, with high-power appliances typically pulling around 10A to avoid tripping the fuse when something else is turned on at the same time. It's just a nice point where wires are easy to handle, plugs are compact, and everything is relatively cheap. The US could have toasters and hair dryers that work as well as European ones if everything was wired for 32A, but you only do that for porch heaters or electric vehicle chargers.
- mystified5016 2y ago
  No, the standard in the US is 15 or 20A. 20 is more popular nowadays. 240V appliances typically get a 35 or 50A circuit. But then you also have to deal with the fact that a lot of homes have wiring that can only handle 10A, but someone has replaced the glass fuse with a 20A breaker. Fun stuff.
  - bardak 2y ago
    I still haven't seen a single 20A domestic appliance though
    - mjevans 2y ago
      I have, though it's semi-prosumer equipment. The largest UPS systems for standard systems, like someone might want for a small home-lab rack, can be found with 20A 120V plugs that work in normal outlets; if they're on a 20A rated circuit like a kitchen refrigerator or bathroom sink outlet (the two most common sorts in rental units). I suspect some beauty products might also use 20A, or in combination easily reach that.
    - bcoates 2y ago
      Very common in light commercial applications but almost unheard of in residential because nobody installs nema 20a sockets in houses even if the circuit can handle it
tgsovlerkhgsel 2y ago
You need the same thickness of wire for 10A regardless of which voltage you have. So with 230V, your 10A wire will let you draw 2.3 kW while someone with 120V and 15A wire would only get 1.8 kW and pay more for the wiring.
andruby 2y ago
I don’t know is toaster are close to max power draw, but kettles certainly are. Most places with 240V regularly have 16A sockets, allowing a maximum draw of 3840W of power. That’s the limit. Cheap fast kettles will often draw 3000W and boil 250ml of water at room tempature in 30s. Kettles in the US are often limited to 15A and thus max 1800W (usually 1500W) and take twice as long (60s) Technology Connections has a great video on this: https://youtu.be/_yMMTVVJI4c https://youtu.be/_yMMTVVJI4c
- andrewla 2y ago
  I mention Impulse Labs and their battery-assisted 120V high power induction range in the comments elsewhere. Seems like a similar concept could be used to make an incredibly powerful kettle; throw in a battery that charges from the mains, and when you ask to boil, send in 20kW and boil the 250ml in 4 seconds. 4.18 J/g/C * 250g * (1/ 20,000 kJ/s) * 75C = 3.918s
  - burnerthrow008 2y ago
    For that order of magnitude to work, in practice, the most challenging aspect will be getting enough surface area between the water and heater. Otherwise, you will very quickly vaporize the water near the heater and the resulting lack of contact will inhibit heating the rest of the water volume.
    - hobs 2y ago
      Yeah that's a great way to start a fire with a lot of steam first :)
    - wbl 2y ago
      Microwave radiation could work to transfer heat in even as boiling initiates in spots. All the best kettles are BIS dual use items.
    - JoshTriplett 2y ago
      If you can transmit that amount of heat that quickly, I think it'd be much more convenient and feasible to have it in the form factor of an instant-boiling-water spout next to the sink, rather than a kettle. Then, rather than having to fill the kettle first, you directly get the amount of hot water you need into the vessel you want it in, and you can put a precise amount of heat into a precise amount of water flowing through a pipe to emit it at the right temperature.
nwallin 2y ago
Correct. You can get the same power with half the voltage by doubling the current. The trouble is the wires. A given wire gauge is limited in its ability to conduct current, not power. So if you double to the current, you'll need to have roughly twice as much copper in your walls, in your fuse panel, in your appliance, etc. Additionally, losses due to heat are proportional to the current. If you double the current and halve the voltage, you'll lose twice as much power by heading the wires. For just a house, this isn't a lot, but it's not zero. This is why US households still have 240V available. If you have a large appliance that requires a lot of power, like an oven, water heater, dryer, L2 EV charger, etc, you really want to use more voltage and less current. Otherwise the wires start getting ridiculous. This is not to say that higher voltage is just necessarily better. Most of the EU and the UK in particular has plugs/outlets which are substantially more robust and difficult to accidentally connect the line voltage to a human. Lots of people talk about how much safer, for instance, UK plugs/outlets are than US plugs. If you look at the numbers though, the UK has more total deaths per year to electrocution than the US, despite the fact the US is substantially more populous. This isn't because of the plugs or the outlets, US plugs really are bad and UK plugs really are good. But overall, the US has less deaths because we have lower voltage; it's not as easy to kill someone with 120V as 240V. So there's a tradeoff. There is no best one size fits all solution.
- masfuerte 2y ago
  Your deaths claim surprised me. AFAICT England has ~10 deaths by electrocution per year. The US has ~100 domestic electrocutions and even more occupational electrocutions.
  - duskwuff 2y ago
    How many of those deaths are attributable to electrical plugs, though? Given the US CPSC report at [1], I suspect that most of them aren't - in fact, one of the leading causes of electrocution deaths is "fractal wood burning". [1]: https://www.cpsc.gov/s3fs-public/Electrocutions-2011-to-2020.pdf https://www.cpsc.gov/s3fs-public/Electrocutions-2011-to-2020...
  - victorbjorklund 2y ago
ajuc 2y ago
You need thicker wires for the same power. Which is why Americans live in constant fear of power extension cords, and people in EU just daisy-chain them with abandon.
- extraduder_ire 2y ago
  If you're in a country that uses type-G plugs, almost* all of those extension cords have fuses that break well below the current that will cause a problem. * Currently using a cable spool which will have problems before blowing the fuse if it's wound up and I draw too much current. It has a thermal cutoff, but I still unspool some extra wire on the floor.
deleted 2y ago
[deleted]

mypgovroom 2y ago

You have a 240v toaster?

xanderlewis 2y ago
Well, closer to 230.
- qayxc 2y ago
  goes to check real quick between 238V and 245V at my outlets.
stuaxo 2y ago
Living in an a country with 240v mains, yep.

bbatha 2y ago

More current needs thicker wires. The average US outlet is wired for 120v15amp. 20 amp circuits are somewhat common, though 20amp receptacles are not. Certainly not enough for commodity appliances to rely on. Going to more than 20amp requires a multiphase circuit which are much more expensive and the plugs are unwieldy and not designed to be plugged and unplugged frequently.

quickthrowman 2y ago
> Going to more than 20amp requires a multiphase circuit There is no multi-phase power available in the vast majority of US houses. A typical residence has a 120/240 split-phase service, which is single-phase only. A service drop is two hot conductors from two of the three transformer phases and a center-tapped (between the two hot legs) neutral conductor. Either hot leg is 120v to ground and line to line is 240V. > https://en.m.wikipedia.org/wiki/Split-phase_electric_power https://en.m.wikipedia.org/wiki/Split-phase_electric_power Single-phase breakers are also available in sizes larger than 20A, usually all the way up to 125A.

generallee5686 2y ago

Having more current running through a wire means thicker wires. Higher voltage means less current to achieve the same power, so thinner wires for the same power. The tradeoff for higher voltage is it's more dangerous (higher chance of arcing etc).

wongarsu 2y ago

Houses are wired for 16A per circuit on both sides of the pond, with high-power appliances typically pulling around 10A to avoid tripping the fuse when something else is turned on at the same time. It's just a nice point where wires are easy to handle, plugs are compact, and everything is relatively cheap. The US could have toasters and hair dryers that work as well as European ones if everything was wired for 32A, but you only do that for porch heaters or electric vehicle chargers.

mystified5016 2y ago
No, the standard in the US is 15 or 20A. 20 is more popular nowadays. 240V appliances typically get a 35 or 50A circuit. But then you also have to deal with the fact that a lot of homes have wiring that can only handle 10A, but someone has replaced the glass fuse with a 20A breaker. Fun stuff.
- bardak 2y ago
  I still haven't seen a single 20A domestic appliance though
  - mjevans 2y ago
    I have, though it's semi-prosumer equipment. The largest UPS systems for standard systems, like someone might want for a small home-lab rack, can be found with 20A 120V plugs that work in normal outlets; if they're on a 20A rated circuit like a kitchen refrigerator or bathroom sink outlet (the two most common sorts in rental units). I suspect some beauty products might also use 20A, or in combination easily reach that.
  - bcoates 2y ago
    Very common in light commercial applications but almost unheard of in residential because nobody installs nema 20a sockets in houses even if the circuit can handle it

tgsovlerkhgsel 2y ago

You need the same thickness of wire for 10A regardless of which voltage you have. So with 230V, your 10A wire will let you draw 2.3 kW while someone with 120V and 15A wire would only get 1.8 kW and pay more for the wiring.

andruby 2y ago

I don’t know is toaster are close to max power draw, but kettles certainly are. Most places with 240V regularly have 16A sockets, allowing a maximum draw of 3840W of power. That’s the limit. Cheap fast kettles will often draw 3000W and boil 250ml of water at room tempature in 30s. Kettles in the US are often limited to 15A and thus max 1800W (usually 1500W) and take twice as long (60s) Technology Connections has a great video on this: https://youtu.be/_yMMTVVJI4c https://youtu.be/_yMMTVVJI4c

andrewla 2y ago
I mention Impulse Labs and their battery-assisted 120V high power induction range in the comments elsewhere. Seems like a similar concept could be used to make an incredibly powerful kettle; throw in a battery that charges from the mains, and when you ask to boil, send in 20kW and boil the 250ml in 4 seconds. 4.18 J/g/C * 250g * (1/ 20,000 kJ/s) * 75C = 3.918s
- burnerthrow008 2y ago
  For that order of magnitude to work, in practice, the most challenging aspect will be getting enough surface area between the water and heater. Otherwise, you will very quickly vaporize the water near the heater and the resulting lack of contact will inhibit heating the rest of the water volume.
  - hobs 2y ago
    Yeah that's a great way to start a fire with a lot of steam first :)
  - wbl 2y ago
    Microwave radiation could work to transfer heat in even as boiling initiates in spots. All the best kettles are BIS dual use items.
  - JoshTriplett 2y ago
    If you can transmit that amount of heat that quickly, I think it'd be much more convenient and feasible to have it in the form factor of an instant-boiling-water spout next to the sink, rather than a kettle. Then, rather than having to fill the kettle first, you directly get the amount of hot water you need into the vessel you want it in, and you can put a precise amount of heat into a precise amount of water flowing through a pipe to emit it at the right temperature.

nwallin 2y ago

Correct. You can get the same power with half the voltage by doubling the current. The trouble is the wires. A given wire gauge is limited in its ability to conduct current, not power. So if you double to the current, you'll need to have roughly twice as much copper in your walls, in your fuse panel, in your appliance, etc. Additionally, losses due to heat are proportional to the current. If you double the current and halve the voltage, you'll lose twice as much power by heading the wires. For just a house, this isn't a lot, but it's not zero. This is why US households still have 240V available. If you have a large appliance that requires a lot of power, like an oven, water heater, dryer, L2 EV charger, etc, you really want to use more voltage and less current. Otherwise the wires start getting ridiculous. This is not to say that higher voltage is just necessarily better. Most of the EU and the UK in particular has plugs/outlets which are substantially more robust and difficult to accidentally connect the line voltage to a human. Lots of people talk about how much safer, for instance, UK plugs/outlets are than US plugs. If you look at the numbers though, the UK has more total deaths per year to electrocution than the US, despite the fact the US is substantially more populous. This isn't because of the plugs or the outlets, US plugs really are bad and UK plugs really are good. But overall, the US has less deaths because we have lower voltage; it's not as easy to kill someone with 120V as 240V. So there's a tradeoff. There is no best one size fits all solution.

masfuerte 2y ago
Your deaths claim surprised me. AFAICT England has ~10 deaths by electrocution per year. The US has ~100 domestic electrocutions and even more occupational electrocutions.
- duskwuff 2y ago
  How many of those deaths are attributable to electrical plugs, though? Given the US CPSC report at [1], I suspect that most of them aren't - in fact, one of the leading causes of electrocution deaths is "fractal wood burning". [1]: https://www.cpsc.gov/s3fs-public/Electrocutions-2011-to-2020.pdf https://www.cpsc.gov/s3fs-public/Electrocutions-2011-to-2020...
- victorbjorklund 2y ago

ajuc 2y ago

You need thicker wires for the same power. Which is why Americans live in constant fear of power extension cords, and people in EU just daisy-chain them with abandon.

extraduder_ire 2y ago
If you're in a country that uses type-G plugs, almost* all of those extension cords have fuses that break well below the current that will cause a problem. * Currently using a cable spool which will have problems before blowing the fuse if it's wound up and I draw too much current. It has a thermal cutoff, but I still unspool some extra wire on the floor.

deleted 2y ago

[deleted]