There isn't actually a maximum kW rating for timer switches.
Among electrical appliances, resistive loads (electric furnaces, heating elements) and inductive loads (water pumps, motors) generally have high power ratings. If directly controlled by a timer switch, they would burn out quickly.
1. Under normal circumstances, a timer switch can directly power appliances with a power rating of 660W or less without any problems.
2. To power larger appliances (greater than 660W), it needs to be used with a 220V AC contactor (because the timer switch is also 220V). This way, even high-power appliances can meet the requirements of the timer switch.
