[Saccharomyces]

AC is alternating current which means it is mostly not at max voltage.  Max power for from a 120 VAC 15 amp circuit is 120*15*sqrt (2)/2 = 1272 W.

RMS voltage does not apply in this rating.

[Saccharomyces]

That is not correct. Almost all conductors have a resistance that increases with increasing temperature. The current will decrease as the element gets hot. If you have a material where the resistance decreases with temperature you can get a runaway condition with the current increasing until the element burns out.

What I meant by that statement is that the resistance of an element is constant with respect to voltage and current for wattage calculations in properly designed circuits (i.e., the resistance of the element does not automatically scale down when using an element designed to operate on a 20A circuit on a 15A circuit). The resistance of the element is only going to drop so much in a properly designed circuit.

Yes, resistance changes with respect to temperature.  Thermal runaway is why one cannot operate most electric elements dry. The phase change of water from liquid to vapor (latent heat of vaporization) dissipates heat, keeping the liquid cool enough that the element does not reach runaway temperature.  If the liquid in which the element is submersed does not make a phase change from liquid to vapor,  then the temperature of the liquid would continue to rise until the element reaches the temperature where thermal runaway occurs.

Finally, yes, electronic components have de-rating temperatures; therefore, operating temperature has to be factored into component selection and system tolerances.

[kramerog]

   I just looked at the load it would be. 15 amps wont work for this, guess I need to get a 1650 watt element for this to work with 15 amp outlet.
     Thank you for the info.

15 amp AC circuit at 110 V will not provide 1650 W because the voltage of AC is not at 110 all the time.  The actual max power is ~ 1155 W.

Huh? No. 110, which in rarely is 110, it's 120Vac, is at 120Vac +/- 3-5% at all times. Maximum power from a 120Vac/15 amp circuit is 1800 watts, but you should stay at 80% with a constant load. That would be 1450 watts.

AC is alternating current which means it is mostly not at max voltage.  Max power for from a 120 VAC 15 amp circuit is 120*15*sqrt (2)/2 = 1272 W.

I don’t know how you came up with those numbers, but 120Vac is a RMS value, in other words it’s a dc equivalent. Very basic electrical theory. 120Vac RMS x 1.414 (square root of 2) = @170 volts. That’s peak voltage. Peak to peak is double that or 340 volts. All those numbers are usually not referenced, just the RMS value.

AC values, unless otherwise stated are RMS values. That includes dielectric ratings. In a resistive circuit, RMS values can be exchanged with DC values. Once inductive and capacitive components are added, the calculations change.

I did not know that!

[Saccharomyces]

Another advantage for using a higher voltage and lower current to produce the same amount of power is that there is less voltage sag.  The voltage drop across a conductor is equal to the current drawn multiplied by the resistance of the conductor.  If we double the voltage, we halve the current draw. Larger diameter conductors made from the same material have less resistance.

[Richard]

Yes, and that is why long-distance transmission lines operate at very high voltages. The loss in transformers to step down the voltage to something usable is less than the loss in the long lines. If and when we ever get superconducting transmission lines that will change but that is a long time in the future.