Introduction: Wiring a Dusk to Dawn Photocell Sensor

Picture of Wiring a Dusk to Dawn Photocell Sensor

I bought a photocell sensor on eBay after learning Lowes, Home Depot, and Walmart were either out of stock on them or did not carry them.  No problem, I thought, 3 wires and it should come with instructions.  It arrived, but with no instructions except on the little plastic part (see second photo).  I am NOT an electrician, but usually can handle easy projects.  If it had 2 wires, it should be easy, but with 3......that's a problem.  I went online to instructables, Youtube, and a few other sites.  Although I could not find anything showing what I needed, I did gather enough to attempt it.  Here is my wiring diagram ( third photo) and instructions:


Connect sensor's black wire to black wire coming from house.
Connect red sensor wire to light's black wire .
Connect all 3 white wires (from house, from sensor and from light) together.

Now wasn't that easy. :-)


CraigM155 (author)2017-06-10

The photo above is exactly what I'm installing today. What size drill bit would I need for the light pole?

CharlesM202 (author)2016-10-05

Their are three wires to and from sensor red black and white I wired each to its color but light still does not work new bulb as well

BillR85 (author)CharlesM2022017-03-19

The red wire should be directly wired to the HOT circuit supply wire the black wire should be connected to the black wire on the lamp you are trying to illuminate and the white to neutral.

sephiroth180 (author)CharlesM2022017-03-18

Call a licenced electrican

Scoobe (author)CharlesM2022016-10-14

Either the light is no good or you miss wired the P/C.

BillR85 (author)2016-08-24

The light switch should always remain in the on position for the photocell to operate automatically. Turn the light switch off first to make sure the lights do in fact turn off to isolate the problem to the wiring at the photocell or the photocell itself. If the lights remain on with the switch off (Highly doubtful) you have something messed up.

I will assume the lights do go out when the switch is off.

With the light switch on you need to test the photo-eyes circuit. This type of photo-eye has electronics in it that increase the resistance and stop the flow of electricity when light hits the sensor. Take a bright flashlight, laser etc and shine it directly on the face of the photo-eye for a short time and the lights should go out. If they don't go out you have a defective photoeye. If they do go out then the photo-eye is in a position where it isn't receiving enough daylight to increase the internal resistance to shut off the current flow thru the photo-eye thus turning off the lights. WIth the photo-eye removed from the circuit, and if you have a ohm meter, you can test the ohms thru the black and red wire coming out of the photoeye. When you shine light in the face of the photo-eye you should see a increase in resistance and when you cover up the photo-eye the resistance should drop to close to zero allowing current to pass.

Photo-eyes are pretty reliable and durable, still most likely cause is that its defective.

Hope this helps.

sephiroth180 (author)BillR852017-03-18

It could be wired wrong

BillR85 (author)sephiroth1802017-03-18

That is always a real possibility and most likely the problem. I went on the assumption it was wired correctly because it is pretty straight forward, but then again you never know for sure...

sephiroth180 (author)BillR852017-03-19

If it's staying on all the time then something's done up wrong. It could just be some sensors turn on for a few mins when initially powered up before turning off and waiting for the light level to drop enough to turn on

BillR85 (author)sephiroth1802017-03-19

Always possible that its too shaded where its at tricking the sensor into turning on.

I had a photocell on my exterior Christmas lights and if the cell was facing into the ground It would turn on much sooner then when I turned it to face away from the ground or wall. So many variables that he really needs to eliminate each problem and making sure its wired properly would be my first step and then covering the sensor with tape or shinning a light into it to determine if the sensor is actually working. I have one on the side of my house for some exterior lights and sure enough the first one I got from the home center was in fact faulty. Noting worse then chasing a problem when the problem is a bad from stock part that one assumes is or should be ok.

grgbar66 (author)2017-01-15

How do I wire to one side of a duplex receptacle so that the other side remains hot.

sephiroth180 (author)grgbar662017-03-18

Hire a licensed electrician

Newguy22 (author)2016-10-21

Can I use this to wire it in at the beginning of a string of outside lights. I have been looking at a set of 10 outside security lights at a great price but they don't have a photo cell eye to work from dusk to dawn, And if so how would I go about wiring and mounting it to a metal R panel building? Thanks

Jwdoer (author)2016-09-02

Will this work when using a 12v battery, solar panel, 12v light, and light sensor to light a flag?

Scoobe (author)Jwdoer2016-10-14

Only if the P/C is rated at 12volts DC.

Scoobe (author)2016-10-14

Reading these comments I have but one thing to suggest, open your
wallets and get a skilled tradesman to properly install your P/C's. It
will save your homes and lives.

ander (author)2016-09-26

Thanks—this was quite helpful!

JeffG101 (author)2016-05-09

Worked perfectly on my garage lanterns! Thanks for the post!

graydog111 (author)JeffG1012016-05-18

Thanks for the reply JeffG101.

dld1947 (author)2016-04-18

I just purchased a Defiant 325 052 photo control. The wiring diagram instructions have black wire to black, and the red and a white wire going to the light I am controlling. With my previous photo control I used the photo control as a switch. Will this work?The black ire wet

graydog111 (author)dld19472016-05-18

I repeat,"I am NOT an electrician". All I can tell you is we use 120VAC with the black wire coming from the switch. The whites all tie together.

JamesK176 (author)2016-05-13

@did1947 you never want to break the white wire connection with any kind of switch. A switch should cut power TO the load (light, appliance) NOT FROM. If the switch is on the white wire, A man touching a light or appliance he has turned off could become the white wire himself. I have experienced this joy.

This is also the trouble with using a 120 switch on a 220 line. The
danger still remains because the apparent "off" has only broken one line
so the other 120 side still is suplying power. A switch should cut off
ALL power to the load.

Just wire as shown above and it will work.

Important not: The many a photocell has a delay built into it. I noticed mine still had my light turn on when I flipped the switch in bright daylight. roughly 1 minute later it turned off. Covering the cell, I felt it click 30 seconds later and the light turned back on. My guess this feature prevents rapid cycling on setups with light feedback.

graydog111 (author)JamesK1762016-05-18

The black wire is from the switch, which stays on all the time.

dld1947 (author)2016-04-18

dld1947 continued

Sorry, but to continue, I used the photo control just like a light switch with the photo control wired between the light white wires. I did not use the black wire at all, in fact I wire nutted it off. Will this work?

Thank you, Dan

dld1947 (author)2016-04-18

dld1947 continued

Sorry, but to continue, I used the photo control just like a light switch with the photo control wired between the light white wires. I did not use the black wire at all, in fact I wire nutted it off. Will this work?

Thank you, Dan

m6255 (author)2016-03-24

so then in a house its always always the white wire that is neutral. Black is always line and if you have a switch leg or say a 3 way or split duplex outlets one is switched. By breaking the connector clip. thats usually red can be other but Never white or black. Ive seen electricians wrap tape around a white wire they tol;d me this tells the next guy this is line. Thats when he said they couldn't pull another wire. They had romex or BX. O don't know if thats true.

Morgan40 (author)2015-11-14

How do you connect a photocell to a probe start light fixture 220v?

graydog111 (author)Morgan40 2015-11-15

Hi Morgan, I'm not an electrician, so you are asking the wrong person. But......IMHO, 220v is just 2 wires with 110v on each and 1 ground wire. You can just connect sensor's black wire to one of the 220v's hot wires. Turn off fuse or breaker first to cut off electricity. 220v is deadly.

A better idea is to call an electrician.

m6255 (author)graydog1112016-03-24

Typically color wise you are right.Its just the opposite of typical DC wiring. DC you usually see Black go to ground (earth) and red is positive. See thats just it in DC you have a positive side and a negative side. In ac you dont. You have the line side coming from the transformer and the neutral technically going back to the transformer or back to its beginning actually through the ground. Thats why on a single phase house you always used to see just 2 wires going to it. Both wires were line neither was neutral. A sparky explained that to me about 30 years ago. Made sense.

m6255 (author)graydog1112016-03-24

as far as 220 being 2 wires and a ground. Used to be thought of like that. But the truth is NO. Technically thats not safe. Thats why these days you see an electric dryer or electric stove with a 4 wire plug. Ive had people move from an old home to a new one I had just built for them. They get there and try to plug their dryer in and find out the sparky put a 4 pronged plug in. The customer says well change it to 3 wire so my dryer works. In most cases a legitimate licensed electrician will NOT CHANGE THE Receptacle. Instead he may say I just happen to have a 4 wire cable in my truck or send you down to the hardware store to buy one. You think as usual its a scam to make more money. No its not. People were getting killed over the years touching an improperly grounded house by say having wet feet in your basement and touching the water valve to turn it on. Some hotdog decided ITZ AC doesnt mater So now that copper pipe is what people would call the HOT wire. When I was a teen ager playing in a band and some of those old tube amps had only 2 pronged plugs no ground and both prongs were the same size. So you plug your amp in and start playing. Your strings are grounded to your amp. The guy running the PA also has an amp and it too has no ground pin and 50 50 change he's going to plug it in opposite of yours. So your rocking along and you're about to sing do-wap into your Shure microphone with the metal screen. And your lips touch the screen while your fingers touch your own guitar strings. WHAM. That happened to me more than once. Happened to almost everybody in a band at one time or another. I don't think I heard of anyone dying but a hell of a lot of swearing went on! I am not sure what it would take to kill someone in that situation. I know its all about the ground because the actual signal is microvolts. Back then they had a dpdt toggle switch on every amp. That was the quick fix from the shocks. Just reversed the polarity. What I dont understand. We went through 2 world wars, invebted the atom bomb went to the moon plus a whole bunch of other stuff but it took till I believe the early1980S before somebody realized they needed to do something about the COLD line and that in fact it can kill you just as dead as the so called HOT (line) voltage.

jeremycrandell (author)2015-07-09

I "made it" but the wall pack is already wired up, tested and working like a charm - no photo proof. Thanks for the diagram!

ani.ibrahim.33 (author)2015-03-03

Wow... this is really helpful ... did my own installation using your diagram. Only thing is .... in my place the live wire is blue in colour. It was pretty easy when it works... Thanks for this information.

Thanks for the reply, ani.ibrahim.33. Glad you could use it.

LarryH5 (author)2015-02-13

Thank you for providing this information, I purchased this sensor and then the fixture went bad, And I had forgotten how to wire the Photo Cell in, This was the perfect diagram, Now all I need to do is actually modify the new fixture to accept the unit, A little hole here and there and I will be good to go.

jackson.ruhanga (author)2014-08-13

In my country we don't use white, what comes out of the house is either black or blue for neutral, and red or brown for live. Recently when i bought a photocell sensor i used your 3rd diagram but i had to connect the red wire from the house to black wire on the sensor and white from the sensor to black from the house. The red wire from the sensor was connected to the load and the system worked perfectly. I found your diagram very useful, thanx.

Glad it helped, Jackson. Thanks for the reply.

Arizno made it! (author)2014-02-27

These are very reliable photo sensors or photoelectric switch as it says on the back. I used these on my instructable. As a matter of fact I found your instructable useful in helping me make mine, Thanks. I selected "I made it" not because I made it but because I used you as a refrence.

Chanio (author)2013-10-12

Very useful reference!

graydog111 (author)Chanio2014-01-17

You are welcome, Chanio. This is really a good sensor. I have bought two more since then and it only took minutes to install them.

Magicninjalord (author)2013-10-12


Thanks Magicninjalord & Chanio. The photocell worked flawlessly last night and turned light off this morning. :-)

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