When manufacturers create power labels for AC electrical devices, what value to they use for the current and voltage? Do they use the RMS of the sine wave? Or do they use the peak of the sine wave? Is peak current/voltage negligible when considering the safety of an AC circuit?
In general, when trying to determine which devices, or how many devices to plug into a circuit without overloading it, should one consider the RMS current/voltage or Peak current/voltage?
For example, let's say I am using a power strip that can accept a maximum of 10 amps. I want to plug in two devices which each have a RMS current of 5 amps, but a peak current of 6 amps. Also the devices accept 120v, but the voltage of the AC current is constantly fluctuating. Why are the devices safe to plug in?