Plugging one power strip into another may seem like an easy way to add outlets to a home office or gaming setup, but it does not increase the amount of power available. Every device connected to the second strip draws electricity through the first one, adding to the load on its plug and internal components.
If that combined load exceeds the first strip’s rating, its wiring can overheat. The resulting heat may damage the casing and insulation and could ignite nearby materials. Power strips have maximum ratings, so the number of sockets they offer does not indicate how much electrical capacity they provide.
If you need more outlets for low-power devices, use a single strip with enough sockets and check that the total load stays within its rating. If you need a longer reach, choose a power strip with a longer cord rather than adding an extension cord, which also has its own limits. A breaker that trips when using one strip should be treated as a warning; adding another strip and distributing the devices does not solve the underlying problem.
Avoid using strips with damaged casings, scorch marks or loose connections. High-power appliances such as space heaters, microwaves and refrigerators should not be plugged into a power strip unless it is rated for them; the guidance in the source recommends plugging these appliances directly into a wall outlet. Surge protectors do not add electrical capacity, either, and should not be daisy-chained. If one strip is not enough, use a separate strip in another wall outlet.
Sources: Engadget.