A cable float switch is a liquid level detection device based on the buoyancy principle, which outputs level signals by actuating an internal switch as the float moves with changing liquid levels. Its core mechanism consists of a miniature switch (such as a microswitch or mercury switch) and a drive mechanism housed within the float. As the float rises or falls with the liquid level, it rotates around a pivot point defined by a counterweight; when it reaches a specific angle—typically 28°±2° for microswitches or 10°±2° for mercury switches—the drive mechanism triggers a change in the switch state, outputting an ON or OFF signal to control devices such as pumps or alarms. Key components include the float body, internal switch, drive mechanism, and a three-core cable. The float is usually made of engineering plastic with a sealed structure (e.g., dual-chamber design) to ensure waterproofing of internal components, while a counterweight at the cable end adjusts the float’s balance to preset the desired trigger level. Level changes cause the float to rotate, either moving a magnetic element toward or away from a reed switch or actuating a microswitch via a lever, thereby opening or closing electrical contacts. The device features a robust, corrosion-resistant, and easy-to-install design, offers high control accuracy (up to ±0.05 m), supports a contact rating of 15 A / 250 VAC, provides a switching life of up to 1 million cycles, and requires no routine maintenance.