Your understanding is correct. It’s actually a very simple calculation: volts x amps = watts. Watts is the amount of total work done.
So to use a water pipe analogy, imagine you have a pressure washer. Volts is the pressure in PSI. Amps in the flow rate in gallons per minute. Watts is how quickly it cleans your sidewalk. Thus, the 500 PSI pressure washer that can put out 2 gallons per minute does about the same amount of cleaning as the 1,000 PSI pressure washer that puts out one gallon per minute. However, as long as the hose can withstand the pressure, pushing out 2 gallons per minute requires a larger diameter hose.
It’s the same way with wiring. The capacity of a wire is measured in amps. So if a device needs say 1200 watts, feeding it was 240v instead of 120v means you can use thinner wires everywhere. Including in the transformer that powers it.
However, this type of gain only really makes a big difference when you get into very high power consumption devices. An electric kettle that takes 1500 w, in the US you are almost maxing out a single 15 amp outlet. In the UK the same kettle is using less than half of the outlets capacity. (Of course they just make a kettle that has twice as much output, because the Brits don’t want to wait for their tea). Amusingly, that 3 kilowatt tea kettle is one of the only places where you get a real perceptible advantage from a 240v system.
My understanding is that higher voltages mean that amperage can be lower. There are also gains in transformer efficiency.
Your understanding is correct. It’s actually a very simple calculation: volts x amps = watts. Watts is the amount of total work done. So to use a water pipe analogy, imagine you have a pressure washer. Volts is the pressure in PSI. Amps in the flow rate in gallons per minute. Watts is how quickly it cleans your sidewalk. Thus, the 500 PSI pressure washer that can put out 2 gallons per minute does about the same amount of cleaning as the 1,000 PSI pressure washer that puts out one gallon per minute. However, as long as the hose can withstand the pressure, pushing out 2 gallons per minute requires a larger diameter hose.
It’s the same way with wiring. The capacity of a wire is measured in amps. So if a device needs say 1200 watts, feeding it was 240v instead of 120v means you can use thinner wires everywhere. Including in the transformer that powers it.
However, this type of gain only really makes a big difference when you get into very high power consumption devices. An electric kettle that takes 1500 w, in the US you are almost maxing out a single 15 amp outlet. In the UK the same kettle is using less than half of the outlets capacity. (Of course they just make a kettle that has twice as much output, because the Brits don’t want to wait for their tea). Amusingly, that 3 kilowatt tea kettle is one of the only places where you get a real perceptible advantage from a 240v system.