Mains electricity is the power that you get from the wall sockets at home, school or work. It's like the power that you use to charge your phone, tablet or any other device.
Mains electricity travels from a power station to your home through cables called power lines. These power lines are like huge straws that are buried underground or attached to poles.
Inside your home, there are wires that run from the wall socket to your devices, so the electricity can flow through them.
But, you should never touch these wires because they are very dangerous! The electricity that flows through them can hurt you badly or even cause death.
So, always remember to be safe around electricity and never touch wires that are exposed, frayed or damaged.