This is when power strips and/or extension leads are plugged into one another.
Answered by Dave, Electrical Safety Expert
This refers to power strips and/or extension leads being plugged into other power strips and/or extension leads to allow you to plug more appliances into the wall socket.
It is bad practice to do this and should be avoided as this presents a serious risk that the wall socket could be overloaded. Move the electrical item closer to the wall socket or first extension lead. Use our overload calculator to check if you’re exceeding the maximum load.