At home we often have to work with electrical tools and appliances (electric, eletronica, furnace, etc.) at a considerable distance from the outlet. And if the extension wire has a greater length (>25 m), it becomes difficult to unwind, to reel and store.
So we decided to make a portable extension cord (see figure). It consists of base, rack and installed on the axis of the spools of wire, one end connected socket, the other plug. Bobbin is installed on axis with curved washers and locked with the wing nut.