Many thanks for the sketch! All is looking fine…
Just a quick question: You drafted two live and neutral wires from mains supply! Are the two live wires both on the same phase? Do you have a 1-phase, 2-phase or 3-phase network at your premises?
I have 1-phase network, so it should be all fine. Well, what should be the problem then? If I remove 1 Shelly and connect one pump to consumer unit without Shelly in between, other Shelly is working correctly on SW switch and again, consumer unit power consumption on second channel is back to 10W - 50W.
Enigma, ha?