Here in NSW, I am lucky to have access to ‘Off Peak’ electricity for heating water. This is electricity at about a third of the normal price that is remotely controlled as to its availability and is only available for a few hours per day. Exactly how many hours and when during the day appears to be one of those ‘Commercial In Confidence’ things. So, I decided to start monitoring when energy was available. I am doing this with a 240V relay connected up to the incoming Off Peak supply. Technically I think this is a violation of the ‘Off Peak’ rules, but I am sure that the electricity company will not complain too much. The relay turns on whenever the incoming supply is turned on. It is that simple.
The output of the relay is connected to the home control system as if it was another light swith, and is wired accordingly. Ignore the blue network cable to the side – it was just a temporary patch cable and is no longer there.