Hello, I'm curious if is safe to connect power cables like on image bellow? Assuming that used wattage is not greater than specified (I think that is around 3-4 kW). And what should I take care of if such connection is done. Thanks in advance.
Curiously, you're showing three different types of sockets (all "weird ass sockets" as Dave would say
). I take it you've used them for illustration purposes only and that the socket in the top of the pic is the type you actuallly use.
Officially it's designated as
CEE 7/3 socket (for CEE 7/4 plug). Also called IEC type F or Schuko. Rated for 250 V / 16 A. If you're in the EU, that would mean a max. of 3680 W (@ 230 V).
I would not call your setup safe if you were to make it permanent. A (temporary) test setup of some sort is another matter, though. However, don't use splitters like that, they're rubbish.
Also note that for 16 A you will need at least 3x1.5 mm
2 wiring. And is your meter capable of measuring the full 16 A continously?