I understand this is a recurring discussion, but I still can't find a concrete answer to this question.
I would like to know how can I inspect the waveform of my UPS output (230V) using an oscilloscope, to find out whether its "sine wave" is actually an acceptable sine wave or one of the high-marketing, low-quality versions.
My idea is to purchase this handheld DMM/oscilloscope and simply stick the probes on the C13 output contacts of the UPS.
There are videos on YouTube of people doing this on mains. I am knowledgeable enough to understand just how dangerous mains voltage is, and I'm aware that I'm not knowledgeable enough to understand how to measure it safely.
The only difference I see between mains and an UPS is that the UPS should not be as dangerous regarding transients, but other than that I believe they're the same thing for practical purposes. The UPS will obviously be unplugged from mains, so it will be working on battery power and it will not be connected to earth ground.
So, is there a safe way to measure the waveform of a UPS using an oscilloscope like that one?
Assuming that the oscilloscope's CAT II rating is honest, that I do not touch the tip of the probes, and that I ensure they do not touch each other, what hazards are present?