Detection of outlet left on

Has anyone ever used a power outlet to detect if something was left on? My wife is notorious for leaving the house in the morning with her curling/straightening iron left on. I have plugged her "weapons of beauty" into a power-monitoring z-wave outlet (Zooz Z-Wave Plus S2 Double Plug ZEN25) in order to prevent the house from burning down.

Just sat down to write the rule for this, and realized I am not sure how to do it. Any of the power monitor capabilities are looking for power usage exceeding a certain level. What I really need is the following:

Trigger--> Power usage past certain number minutes
Action--> Turn off outlet, Wait a certain amount of time, "re-arm" the outlet by turning it back on

I want the re-arm to eliminate the need for her to turn the outlet on and then turn on the iron (would cause low WAF). That part is easy using RM (turn off, delay, turn on). The tricky part is the power usage. It cant be looking for something over XXX Watts since when it is actively being used, power will still be legitimately needed. Should be something more like "1000 Watts consumed for 10 minutes".

Any ideas?

How about trigger on power and then turn off with a delay of 1 hour?
Something like this

This is just an idea.
i don't quite understand the re-arm. That would turn the iron back on, making it hot again.

This would then be something like this?

Tested this with a Coolcam plug (osram power meter didn't work)

You might have to use private boolean to make this work. I had a similar problem with my water heater and a smart plug. It would do unexpected things with just a simple rule.

  • The first rule would set the private boolean, IF power is 1000 AND for 90 minutes THEN TRUE
  • Else IF would be False

Second rule would use the private boolean as the trigger and "reset" the rule.

See my example here: Will this rule work as intended? Washer on changes water heater mode

1 Like

Do you have to measure whether she's left any of them on? If she leaves in the morning, shouldn't you just turn the outlet off regardless? That seems like it would be a lot more fool-proof. Something like a curling iron is only going to pull power while it's heating so you're going to see power usage go up and down radically over time. I'm not sure power reporting for a straight measurement is going to catch that.

There are many ways to skin a cat. After thinking about it, you might be right about the power cycling on the iron. He would have to test to see how it reacts.

If you had a smart light switch in the same bathroom, you could turn off the iron outlet when the light switch went off (maybe automatically turn light off as safeguard) and only turn the outlet back on if the switch is turned on between 6 AM and 8 AM or something.

Rather than trying to calculate whether the appliance has been left on, how about setting up a small siren or TTS to announce that "the iron is still on" after 15mins or so. It could also send a Push notification.
That way your not Powering down the power outlet, which I can understand would have the potential to cause additional grief.

1 Like

All good points by everyone! I think that the iron is like a 'push-on' type thing where it only comes on when you press the button...even if it's plugged in. The power-cycling is not something I considered. @njanda idea won't work as there not be anyone home to respond to that announcement, but @Ryan780 may have the right idea. Maybe I am overthinking this. Just turn it off and be done. At least that way I am sure the house doesn't burn down or countertop get scorched. I will do some measurements and see what the power looks like but may end up just killing the outlet and be done.

1 Like

If she has a smart phone why not just setup it up as a presence device and create a rule to have the plug shutoff when she leaves?


Or use a motion sensor, turn the outlet on when there's motion.
But then there's always that clicky noise when you walk in.. might not be the best solution.

My wife loves to sew but occasionally forgets to unplug the iron and it doesn't turn off by itself so I have the outlet turn off when everyone leaves, turn on when we arrive and (rule pictured) turn off if the sewing room lights are off and the outlet power draw is over 100 (I choose 100 as we sometimes leave a fan on in the room at night and the iron will draw more than 800 when its heating so the rule works well for our needs. I also have it speak when it turns off so my wife knows and there is a button in the room to turn the outlet back on

Do you need to go to this effort then? No button pushed=no house burned to the ground. I worried similarly about my daughter's straightening iron, but then realized that it turns off automatically. No need for concern.


Thanks everyone for your suggestions! I ended up following @Vettester suggestion and created a rule that shuts the outlet off when she leaves and turns it on when she comes home.