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bigmacfann 08-02-2010 12:43 PM

Issue with a definite purpose contactor and photo cell.

I have an apartment building that I recently had someone do some electrical work on for me. He did fine and the stuff he did passed the electrical inspection with the city. He is nowhere to be found now. Here's the story:

I wanted all the exterior lights to be on a photo cell so the lights would go on at dusk and off at dawn. He installed a Siemens Furnas Definite Purpose Controller; cat number 42CF15AF and a Westek Photocontrol Model SW103CTC photo cell. It was daytime when he installed it, so we pushed the button in the middle of the controller to verify that the lights would work and they did. Everything seemed fine, I paid him and that's that. The following day came along and I was driving home around dusk, I was curious if the lights would already be on from the level of darkness or if I would have to adjust the sensitivity or something. When I got there, the lights weren't on, so, now I needed to find out what the problem was. Here I am. I took photos of both items. Could someone give me an idea of how to wire these things up correctly? I just did work on 5 AFCIs myself on a hot panel, so I'm not inept when it comes to electrical work. This obviously won't be hot when I work on it because there's no need in this case. Here are two images:


P.S. The electrical tape on the end of the photo cell was there for me to test it out...

delta force 08-02-2010 01:21 PM

A standard 15 amp single pole breaker I assume and is dedicated to the
exterior lights.............

The hot wire from the breaker goes to the "LINE" terminal,the neutral wire goes to the "NEUTRAL" terminal both at the photocell module.A switch leg wire will go from the "LOAD" terminal on the photocell to the lights along with a spliced neutral picked up at the photocell.

When the photocell sensor closes the electronic circuitry in the photo cell and it in turn picks up an integral electronic relay closing the load circuitry and the "LOAD" terminal becomes hot turning the lights on.In the morning when the photocell sensor now opens the electronic circuitry dropping out the relay which in this case is an off delay and it remains closed for the preset time.

When testing the photocell by actuating the sensor by hand remember that the photocell must have power(120v) so be careful.

Check your local AHJ to see if a ground on the lights is required or it may be required by the manufacturer,

A 3 position "HAND-OFF-AUTO" selector switch would be nice to have in case the PC failed.


bigmacfann 08-02-2010 01:51 PM

Delta Force,

I appreciate your response! In looking at the controller, I am having some difficulty seeing where the Line, Neutral and Load connect. The photocell is easy to tell which wire is which. If you look closely at the bottom of the image of the controller, you'll see he has the red wire from the photo cell and the white wire from the photo cell connected to the controller. The black wire from the photocell is twisted in a wire nut and connects to the controller on the bottom as well as goes to the load center. There is another black wire that comes in from the load center and connects to the top of the controller. I'll take a picture of the whole system a little better and post it if I have further issues. Thanks again.

delta force 08-02-2010 03:33 PM

The red wire from the PC is the switch leg circuit to energize the contactor coil,the white is the neutral to the coil from the PC and is spliced somewhere else to provide the light and PC neutral, one of the black wires is from the wire nut you spoke of and goes on to the PC from the wire nut the other black wire is the hot to the line side of the contactor main switch,the other side (also black)of the main switch has to go the lights.

I'm pretty sure that is what it is can you meter it out and verify?

Note in the image, you have 4 terminals and you got 4 wires,I think there is an oops in the wiring when that one terminal does not have a wire and one of the others has 2 wires,kinda suspicious:whistling2:


Yoyizit 08-02-2010 03:56 PM

Test the photocell assembly separately by powering it, running a lamp from the red wire to the neutral wire and taping over the cell and waiting your two minutes for the bimetallic switch to make contact.

I guess you should also try to figure out which of these contactor terminals goes to the 120 V coil.

delta force 08-02-2010 04:29 PM

We are riding on the same train Yoyizit:thumbsup:


Proby 08-02-2010 04:44 PM

You need to have a licensed electrician work on this. This is not a DIY project, it is work on an apartment building in the state of California, a state that requires a licensed electrician to do electrical work on multifamily dwellings.

delta force 08-02-2010 04:50 PM

Right on Proby,,,,,,,,,,,,I assumed the electrician referenced in the OP fit that mold, maybe not.


bigmacfann 08-02-2010 06:39 PM

Here are 3 pictures to help illustrate the whole thing a little better:




Based on this, could someone give me a wiring diagram? I used wire 1, 2 and 3 because there are 3 black wires coming from the load center. Wires 1 and 2 plug into 20 amp breakers and wire 3 is the wire coming from the lighting circuit. In this current configuration I can press the black button in the center of the controller and all the exterior lights come on. The photocell is not causing the controller to do anything which makes me think the photocell needs to be wired up differently. The guy that originally wired this up is a commercial electrician, but I can't get a hold of him and if there were any trade I'm comfortable with, it's electrical -- plus, I own this place, so I take all the responsibility. Thank you for your help everyone.

Yoyizit 08-02-2010 06:56 PM


Originally Posted by delta force (Post 479370)
We are riding on the same train Yoyizit:thumbsup:


I can't believe Siemens doesn't label their terminals. :(:mad::huh::eek:

One reason that it doesn't work is that the photocell neutral is not supplying power to the photocell.

nap 08-02-2010 07:25 PM


Originally Posted by delta force (Post 479374)
Right on Proby,,,,,,,,,,,,I assumed the electrician referenced in the OP fit that mold, maybe not.


well, OP said electrician was done and left. The guy asking questions is the owner/manager. That means there is not an electrician doing the work and based on the simple screw up that is causing the problem, I would say it wasn't an electrician doing the work before either.

and not only is the electrical a simple screw up that an electrician shouldn't miss, the installation of the box is not to code either.

Oh, on top of everything else, OP never said it was an electrician doing the work, just ""someone"

delta force 08-02-2010 07:26 PM

Here is the answer in my opinion

#1 is the hot from the breaker to the contactor main power contact,line side.

#2 is the hot for the PC.

#3 is the is the switch leg from load side of the contactor main power contact and goes to the lights.

The red is the switch leg from the PC to the hot side of the contactor coil.

White is the neutral for both the PC and the contactor coil

Now it appears the neutral from the load center is missing,if you find that and connect it to the contactor in parallel with the white that is already there and I think you got it.

A neutral conductor must leave the the load center and pick up the lights
and then backfeed the contactor but it has been dropped somewhere.

I still don't think the contactor is wired correctly.

If you push the test button on the contactor and it makes a closure between the red wire and #3 and the photocell is made(or failed closed) the lights will come on,,,,,,,,,,,but as you say it doesn't work as wired,that why I feel it is wrong,,,,,,,,,the red wire and #3 should not be the same point in the schematic.

If you want a schematic I will post one up


nap 08-02-2010 07:35 PM

at least give him correct info if you are going to do it.

You are missing a neutral from the panel to the contactor and the PC. Other than that, it will work.

and since the guy said he was going to work safe, he might turn off the breakers while he has the contactor flopping around like he does.

frenchelectrican 08-02-2010 07:57 PM

I am in the same boat you allready missing a netural conductor to get the photocell working and the contractor as well.


Make sure you draw up a correct connection for it.

Now to the OP please turn off the breaker now to the luminaire circuit and the contractor a short or arc to the contractor can destory the Photocell very fast so turn it off please.

Do not turn it back on until the netural conductor is there to get it function properly.


bigmacfann 08-02-2010 08:03 PM

To clarify to everyone concerned (thank you for the concern BTW), I have the entire system shut off at the main breaker. I'm not interested in playing with a hot system for this!! :-) In addition, I am the owner of this property. The original person that did this works for an electrical contractor in Arizona and did it as a quick favor. At the time he did the work, we had no power from Southern California Edison yet. We had to power it with a generator to test it.

Here's what I think everyone is telling me, I need to connect a white wire from where the PC's white wire is connected to the contactor to the neutral bar in the load center. Does that sound correct? Maybe I should take a look at that schematic "delta force" was talking about. Thanks again!

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