Typically, your pool equipment will be connected directly to a power source. Without a pool timer or an automated system, your equipment would run 24/7/365. With a pool timer, the power between your system and the source is disconnected and reconnected for the times you’ve set your equipment to run. A pool timer, most frequently called a time clock mechanism, is an intermediary between your equipment set and that power source. Time clock mechanisms are mechanical in nature and most models look like an extension cord connected to a large box with an internal, mechanical clock.
How do I run my pool equipment?
by Jeff Manning