Earthing doesn’t “run” on electricity. Your Earthing product is connected to the energy of the Earth, not to the electricity that operates your lights and appliances. If you plug your Earthing product into the ground (earth) port of your wall outlet, you are simply making contact with the ground (earth) wire in that hole that connects to other outlets in your house and is attached to a large ground rod outside. Whether your power is on or off, doesn’t matter. As long as you have contact with the Earth, by being barefoot outside, or using an Earthing product indoors that is connected to the Earth, either via a grounded (earthed) wall outlet or a separate ground rod outside, you are grounded.