1) Never did I write that 120/240 was NOT the standard.
2) Voltage IS attributed to heat. Whether it be from a 50 amp service to a 200 amp service. "You size the wiring to match the max current allowed by the breaker". I wonder why. Oh yeah, BECAUSE IT WILL HEAT UP. "They tell you the max current that a particular size conductor can safely carry." Hence the redundancy.
3) "Higher voltages require better insulation to prevent arcing." No!? Really? Insulation on any wire is there to prevent arcing. It's also there to prevent electron loss, which can be pretty hot. Besides, what is an arc but a simple loss of electrons?
The 120/240 standard is in place to successfully power 110/220 devices reliably. Since power is drawn from a circuit, having an extra 10 volts (in 110 running on a 120) and 20 volts (in 220 on a 240 circuit) as a redundancy AS TO NOT RISK WIRE HEATING was established. Likewise, you could run a 110V device on a 220 circuit because you would be drawing only 110 volts on a circuit designed to handle 240. Run a 220V device on a 120 and the extra power (electrons) drawn will heat up the insufficiently insulated wire.
Amperage. Amp=watts/voltage. For example, a 220 (on a 240V circuit) volt appliance consumes 480 watts of power, How much current does it draw? 2 amps. 480/240=2. Why not divide it by 220? Because the circuit is already setup for 240V. Am I denying that a high-amperage device causes unnecessary heating? No! Are amps solely responsible for unnecessary heating? No! A vacuum may take 660 watts. 660/120=5.5 amps serviced. Does you vacuum spontaneously combust? Didn't think so.
Tell me again how I'm supposed to "know" about it.