I installed a halogen floodlight today so I adjusted the sensor tonight for it to work and it did. I thought by turning on the switch the light would stay on and when it is turned off the sensor would pick up movement and come on.

Do I need to leave the light switch turned on all the time?

  • I have similar lights to the front which are turned off but come on when someone passes or stay on if I turn on the light switch. I want this to do the same. Apr 1, 2015 at 23:59
  • Can you provide the manufacture and model of the sensor switch, please ?
    – Some Guy
    Apr 2, 2015 at 0:07
  • Home protector......Walter-werkzeuge model WW HF -14 Apr 2, 2015 at 0:16

1 Answer 1


Unless the sensor/light is connected directly to power, the switch will always have to be in the ON position for the light to come on.

The switch is installed to interrupt the ungrounded (hot) conductor, so that when it's in the OFF position no power goes to the light. If you want power to the light, you'll have to leave the switch on.

In other news, some motion sensors use switch toggling to change modes or settings. So turning the switch off/on could cause the sensor to change modes.

Read the documentation that came with the fixture, to determine how to properly operate the sensor.

  • Tester is right about the switch being used to toggle the mode of the light, at least with every one I've ever seen. The usual procedure is as follows: To keep the light on regardless of motion, turn the switch off then back on quickly; to let the sensor decide when the light should be on, you turn it off for at least 10 seconds then back on. Check the manual to make sure this is right for your sensor. Apr 2, 2015 at 15:33
  • Some models have what's called a "dusk to dawn" mode. Where the light will come on at dusk (when ambient light levels drop below a certain threshold), and turn off at dawn (when ambient light levels raise above a certain threshold).
    – Tester101
    Apr 2, 2015 at 15:36
  • @Tester101, switch that around: "on at dusk... off at dawn", I understood your point but... :) Apr 3, 2015 at 14:11

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