TIL my microwave uses 100% of the 15A a North American plug can provide.
The voltage on that circuit doesn't sag appreciably from 120V under load, so it's using 200W more than the nameplate says it should, 1600W.
I'm a bit surprised that Black & Decker used such close margins; my kettle draws a more reasonable 13A.
It's no wonder they changed the building codes here to require 20A outlets in kitchens... 😂
@121 My Kill-A-Watt is supposed to be a true-RMS meter, and can measure both Watts and VA (apparent power). The apparent power reads a bit higher than the true power. But it's pretty close. Microwave ovens aren't pure resistive loads, because the magneton doesn't run on 60HZ AC. But manufacturers are expected to correct power factors these days, so no surprise that the two values are reasonably close.
@121 The power usage does go down a bit over time, probably due to the electronics heating up and thus internal resistances increasing. So the higher than expected power usage might just be the manufacturer ensuring it meets a minimum heating power, regardless of manufacturing tolerances.
@pete i didn't realize (or, more likely, forgot) that 120/220 V are not peak but actually RMS voltage values
@pete not sure what manifacturers advertise as power output, but A/C *effective* power output is 0.5*I^2*R = 0.5*I*V (because cosine squared averages to 0.5). However, it could well be they specify maximum power output, just I*V for marketing purposes