How to Fix a Dusk to Dawn Light Fixture - Ask the Electrician This could also occur when a photo cell has been installed ahead of the dusk to dawn light fixture. Therefore, it would be best to control a standard light fixture with a photocell, or have a dusk to dawn light fixture with the typical motion control module that has a constant power source. How to Wire a Photocell Switch | Hunker Photocell switches are typically used on outdoor lighting. This allows the power source for the light to remain on at all times. The photocell switch will then turn the light on at a predetermined time, generally dusk, and off when the sun rises. Power must always be applied to the photocell..
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