Hi Michal,
I don't know, if I understand you 100%...
I try to recap:
There are two lights and only one is to turn on/off by a switch - the other one is turned on all time.
You have two wires: One to the switch and after that to the lamp? The other wire directly to the always on lamp?
Now you want to control both lights with the existing switch?
That means both lights are corresponding on or off? No seperat control wanted?
OK - if it should work as I described, you can install a Shelly2.5 in your Circuit breaker box.
When you use output 1 for the switched lamp and outputl 2 for the always on lamp you have to wire the shelly in this way:
Shelly-N connect to Supply-Neutral
Shelly-L connect to Supply-Life/Phase from the circuit breaker
Shelly-O1 connect to the brown wire in your picture
Shelly-O2 connect to the red wire in your picture
Shelly-SW1 no connection
Shelly-SW2 no connection
Now, if you turn on the switch and the relay of Shelly output 1 (channel 0) is on the lamp should be lighted and a power consumption will be detected by the Shelly. This value can be used to control the second output (O2, channel 1) of the Shelly that manages the red wired lamp.
The configuration of the Shelly should be:
General/both channels: Settings / Mode / Relay
Output1/channel0: Settings / Power on default mode / ON
Output1/channel1: Settings / Power on default mode / OFF
To control the 2. Lamp you have to create two scenes:
Because I do not know anything about the power consumption of the lamp with the switch ich use more than 5 Watt for the level to turn on the 2.lamp and less than 4 Watt to turn it off.
Hope it works with your intstallation.
Now - if the Shelly-O1 is on you can turn on the first lamp with the switch and the Shelly will activate its O2 to lighten the second lamp.
Turning off the switch will shut down the Shelly O2.
Good luck - please give feedback
Hello Wolfgang,
yes, you get it right.
Thanks for very good explanation. I made everytning you wrote step by step. And... it is working 
What I don't like is the big lag between - I think it is because of the rule is run through some Allterco servers and flies all over the internet.
1st solution: I have OpenHAB running, I will try to do it locally later, but the biggest problem will be probably polling the Shelly every X seconds - this will define the lag time probably.
2nd solution: will be probably to flash alternatife FW and create the rule inside of the Shelly?
3rd solution: Install one Shelly under the switch and create the rule through OpenHAB to switch on the "always on - red" line.
Thanks again!
Michal
Hi,
sounds good - I never used scenes.
My idea/explanation was created really "offline"...
I think the lag is a combination of Internetspeed/Cloudserver and the Powermeter of the shelly. The meter is not sending/testing every Millisecond. I think ist is around each 1 or 2 sec.
The solution I created was because of your requirement only to use one Shelly-device.
I would prefer two Shelly (Shelly 1 or Shelly 1PM) to have a full single control for each lamp and additionally it will work nearly without a noticeable delay.
With two shelly you can use the existing switch to turn on/off the first lamp manually and the second lamp corresponding or indenpendent. But also you can control each lamp with the App.
I don't know OpenHab enough but I think, it is compareable to ioBroker (I use this).
With such a control system you can manage the devices/lamps again much more comfortable.
