Quote Originally Posted by oj88 View Post
Particularly for wattage and amperage, those are usually the stated maximum that the appliance will ever require. They're meant to help contractors and electricians design the proper circuit for it (correct-rated wires, switches, plugs, and breakers).

A watt-meter or power meter is still necessary if you need to gather realtime power consumption. As stated above, there's tons of them on Lazada.

DO NOT use it to measure the output of a non-sine wave UPS. My old one popped, sizzled, and died after just a couple of minutes while measuring the output from a cheap UPS.
how does one know, which is safe to use, and which is not?