The timer will stop accumulating when the plugged-in appliance drops to 0 watts. You can use this feature to measure actual run-time of appliances. For example, you can plug your fridge in for 24 hours and observe the clock to see how much of that time the compressor was actually running. This is great for troubleshooting ‘problem’ loads around your home.
The Timer, Cost and kWh will all continue to accumulate until you hit the master reset button in the middle of the Power Meter.