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AssuredElectrical, Master Electrician
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Hi - Im attempting to wire a line-in photocell onto 2 outside

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Hi - I'm attempting to wire a line-in photocell onto 2 outside lights. Both lights are controlled from a switch inside the house. The first light has 2 black wires and a white wire. The second has 1 black and 1 white wire. I have 2 line-in photocells, each of which has 1 black wire coming in and 1 coming out. I had it working for a time by trying different combinations of where I put the black wire from the photocell to the two black wires in the first light. But after a few days both lights stayed off. I replaced the bulbs, and one light then came on and stayed on regardless of light conditions. My question is whether it is possible to use these line-in photocells in my application - whether both photocells are needed, and how to make it work.
Welcome. My name is XXXXX XXXXX would be glad to assist.

Could you provide a bit more information please?

Start at the first light:
Power from the switch comes to the light, black and white wire, correct?

Power to the 2nd light is connected to the first light? Black and white?

How did you connect the photo cells inline?

Normally photo cells have black,red and white wires?
What do yours have?

Customer: replied 4 years ago.

Thanks for quick reply Tommy - first light has 2 black wires and one white. I assume one of the black wires and the white wire go on to the second light. Also assume power from the switch, as you said, goes into the first light via black and white wires. The photocells have only a black wire going in and a black wire going out.

Ok, thanks for the information.

At the first, there should be 2 blacks and 2 white wires which represents 2 cables.

Did a white break off? come loose?

The photo cells must be the miniature inline photo cells.
Do you have a Make and Model?

Many of those mini units are not 120 volt rated but 12 volt, wish to be sure what you have.
Customer: replied 4 years ago.

Thanks - believe this is the model:

Regarding the white wire in the second light, does not appear anything has been broken off, there is only one white wire coming from behind the wall into the light fixture.

Ok, thanks.
Familiar with those. They are the type they install in the fixtures themselves for a very small footprint and dont show so much as the large ones.

This can be very tricky to keep for any period, as they fail often.

Below is how they should have been placed inline on the wiring at the 2 light locations.

Do not know why only one white and 2 blacks at the first fixture, but wiring is still the same.

Does yours like that?

Customer: replied 4 years ago.

Yes - but I have since the initial wiring (which looked just like your diagram) I have taken off the photocell from the second light. Seems to me that if the power goes off or on to the first light it should also control the second light? But obviously you are the expert, not me. I can re-wire it to reattach the photocell to the second light, but in view of your thought that these fail quickly and easily, maybe I should go with a different type. Is there one you recommend which has a smaller footprint, that will control both lights with one hookup?

If both lights are controlled by the same switch, turning the switch off should shut down power to both photo cells and lights.

Those units are minatures and are not made for more than 1 bulb.

Probably why they burnt out quicker than normal.

They will not control 2 bulbs or 2 fixtures.

There are small wattage cells.

In order to control both lights off of one photo cell, you will have to find where the wires from the lights go and connect on the other end.

With one white at each location, your lights are not wired between each other but meet at the switch or a junction box someplace.

If they were connected directly to each other, you would have 2 whites at that first fixture and not one.

As for the type, if you are controlling 2 fixtures, you will need the large photo cells, as they are the only ones to carry that type of wattage.
Higher wattage cells have 3 wires.

Those mini button style are made for like 60 watts maximum and they dont make the smaller ones to control large flood lights.

Larger ones like below are made for the higher wattage.
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