Just tested the Shelly 1PM
Findings:
– you NEED to use the internal switch / you can’t bypass it (if you want to measure)
– set „Settings -> Power on default Mode“ to „ON“ if you use it inline
– the measurement is not as exact as the 3EM, as it allways assumes 220V for it’s calculation (maybe the 1EM is better)
– measurement can be ajusted… a bit… get a Voltage reeding „Your Voltage/220v=0,x-1,x“
(In my case 235v/220v=1,06) [yes, I’m getting 235v at the plug]
– the measurement correction you find in „Settings -> Power Consumption Correction“
— Please note: your voltage changes over the day & if you set the line under load, volage will drop, so consider measuring under load.
– for that connect:
— MAINS N to N
— MAINS L to L1
— O to your Load/Production
– you can connect a Switch between L & SW -> „Settings -> Power on default Mode“ to „Switch“ so you can use a switch to operate the internal one (if you have the usecase for that… you know it)
– the Internal Switch is… next to useless for me, I can’t use it to trigger a seperate contactor for „loadswitching“
You can get better hardware (1EM/3EM) for more money (50/130€) but if you are fine with this approximate values… ~16€ is pretty good for the value you get.