Many plants require a certain light-cycle (often 12/12) in order to begin flowering or fruiting. In order to switch a high power hydroponic indoor HPS grow-light on and off automatically usually requires a combination of a mains time-switch and a relay or contactor. A standard time-switch used on its own for this purpose will usually arc-out and die very quickly. All our relays, contactors and timeswitches are from quality manufacturers and will give you peace of mind when it comes to reliably and safely switching your grow-lights on and off at the correct times.
A standard time switch is not robust enough to switch large wattage grow light directly. The switches inside of them cannot handle the current change at switch on or switch off. This often causes arcing which destroys the switch contacts.
Instead, a heavy duty switch is used to power the lights. A time switch simply controls the heavy duty switch which is called a relay or contactor.