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-   -   2 wire photocell? (http://www.diychatroom.com/f18/2-wire-photocell-143821/)

lfwallace 05-15-2012 10:41 AM

2 wire photocell?
 
I've taken over the electrical trim work in a house I'm building, after letting an electrician rough the entire home. I instructed the electrician to include a run for a photocell at the front of the house to control my garage lights. However, I noticed that he only ran a single 14/2 run to the photocell location. It seems, however, that there are only 3-wire photcells (black, neutral, red). I've tried utilizing the black as the hot (black to black) and red (red to white) on the load side, without using the neutral since I don't have the additional wires. Doing this just leaves the lights on all the time.

Why would the electrician run a single cable to the photocell? Is there a 2 wire photocell available out there or a 3-wire that can work in a 2-wire configuration?

JulieMor 05-15-2012 10:53 AM

He was probably thinking of a simple switch when he ran the wires. I've seen two wire photocells but I can't think of ever having installed one. Do an Internet search, just make sure it's rated for 125 volts.

lfwallace 05-15-2012 11:53 AM

Can I just use the ground as neutral, since they're so closely related anyway?

jcrack_corn 05-15-2012 12:13 PM

no, you cant, lol.

give more info about the install, it may be easy to call him back to run a 14/2 to the light, and cutting/removing whatever is currently going to the light box.... rather than rewire with 14/3.

lfwallace 05-15-2012 12:57 PM

Actually, let me rephrase my question. The photocell does not use ground. It's got a black, red, and white. The black is for hot, the red is for the load, and the white is for neutral. From the 14/2, I can wire black to black and the white to red (using the white as the return to load). This leaves the copper ground wire not used. So couldn't I just take the copper wire and hook it to neutral on both ends? The only difference between this and using an actual neutral is that there is no jacket around the copper wire.

Code05 05-15-2012 01:00 PM

Quote:

Originally Posted by lfwallace (Post 921911)
Actually, let me rephrase my question. The photocell does not use ground. It's got a black, red, and white. The black is for hot, the red is for the load, and the white is for neutral. From the 14/2, I can wire black to black and the white to red (using the white as the return to load). This leaves the copper ground wire not used. So couldn't I just take the copper wire and hook it to neutral on both ends? The only difference between this and using an actual neutral is that there is no jacket around the copper wire.

No, you cannot!!!

M3 Pete 05-15-2012 02:51 PM

Quote:

Originally Posted by lfwallace (Post 921911)
The only difference between this and using an actual neutral is that there is no jacket around the copper wire.

and I believe that is the critical difference. Unlike a ground, the third wire of the photocell (a neutral) has current flow as part of its regular operation. Thus, it has to be jacketed.

Can it be done the way you suggest? Sure.

Is it safe? Is it code? No and no.

Speedy Petey 05-15-2012 03:15 PM

Quote:

Originally Posted by lfwallace (Post 921911)
The only difference between this and using an actual neutral is that there is no jacket around the copper wire.

The physical difference, yes. The practical difference, NOT A CHANCE!

They are NOT closely related either.

These two statements of your only prove that you are NOT experienced enough complete this project.

frenchelectrican 05-16-2012 12:59 AM

Quote:

Originally Posted by lfwallace (Post 921821)
I've taken over the electrical trim work in a house I'm building, after letting an electrician rough the entire home. I instructed the electrician to include a run for a photocell at the front of the house to control my garage lights. However, I noticed that he only ran a single 14/2 run to the photocell location. It seems, however, that there are only 3-wire photcells (black, neutral, red). I've tried utilizing the black as the hot (black to black) and red (red to white) on the load side, without using the neutral since I don't have the additional wires. Doing this just leaves the lights on all the time.

Why would the electrician run a single cable to the photocell? Is there a 2 wire photocell available out there or a 3-wire that can work in a 2-wire configuration?

I wrote the underline that part whoever that electrician is done ran that 14-2 conductor there may misunderstood what your intened plan if that is true you will have to call him back and change that one to proper 14-3 conductor that is the only way you can get the photocell to function properly.

I never really trust the two wire photocell devices at all they are useally not worth a merde.

I always run 3 conductor and that useally take care of that.

Merci,
Marc

f800 11-04-2012 11:14 AM

I know this post is a little old, but I just stumbled upon it. I have a low voltage system from Vista. My system uses a timer (rpm-100) that has a two wire photocell. It only last 4-6 months before it burns out. Problem is, the photocell costs $28. Is there a relatively cheap two wire photocell that I can connect to the Vista photocell connector?


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