I have a outdoor light fixture I want to put on a 7 Day Astro timer, the switch is a single pole with two wires, one being black and the other yellow which is the neutral..

OK Now Honeywell makes two timers one being 3 wire and the other two but the two wire one needs a 40W min load.. the fixture outside is a 35W LED fixture so I don't know if that would work..

In the case that it does not can I use the 3 wire timer on a 2 wire fixture? If I remember the timer colors are red, black & blue.

 

A neutral isn't yellow.Yes, but only if one of the colors is white and you have a neutral in the switch box.

 

Building was built in '64 the yellow wire is wirenutted to a white wire in the switch box.. Who knows why they did that.. Runs in the conduit as well.

 

Lots of members have called old discolored white wires yellow or tan. Can you post a pictures of the box showing the wires? http://www.doityourself.com/forum/li...-pictures.html A true yellow wire in conduit (single phase) is often the switched hot.

 

Well I did not take a picture of the box where the fixture is but I took one yesterday of the switch box.

The switch for the light is the one in the middle and as you can see it's red and black, but at the fixture it was white and black..

that yellow wire is running in the conduit and so is white.. but I don't know why that color was picked.

The other switch may go to some lights above but not sure yet.

 

You can't use Tiny pic for pictures. http://www.doityourself.com/forum/li...-pictures.html

 

We need a better picture of the box with all the switches pulled out so we can see all the wires. Please reduce the picture size to a width of 800-900px. With an LED light you definitely need a timer that has a neutral but I can't see clearly the white wire you spoke of. Is there a group of white wires connected only to each other behind the far right switch?

 

I see a yellow and white in the first conduit.
I see a blue, possibly two yellows and a white wire in the second conduit.

It doesn't appear that the yellows are neutrals.

 

So can i use the timer for this?

 

I know of no cables that have yellow wires and few, if any, cables have printing on the individual conductors. That tells me that you have a conduit system with individual wires. As such, all white wires should be neutrals and all colors other than white, grey and green are "hot" conductors.

I suspect that the red is the power supply and the yellows are switched power to the various loads. You state that the fixture you opened had white and black and that would be the correct colors in a light fixture. You also stated that at the switch you had a red and black and that also coincides with proper color coding.

At this point I would state that you probably can use the timer you selected but to be certain you need to pull all three switches out of the box and spread the wires so that we can see ALL of the wires and connections.

 

I hope this helps? This is with all 3 out.. the one I want the timer on is the one in the middle but if it works I need to move the switch over.

 

If the timer has a neural you can definitely use it with LEDs.

 

So I was curious of what the blue and yellow wires are for? Most things I've searched don't really touch on wiring done in the 60's.. the early 60's.

 

It isn't that the wiring is from the '60s but that it is conduit. Most books about residential wiring assume cable. With cable there is a very limited number of colors and combinations. With conduit used for single phase residential only the neutral and ground colors are set by code. Hots can be any color (except white, gray green). However there are some colors most pros use. Black will usually be an unswitched hot. Yellow will be a switched hot. Red is slightly more likely to be a switched hot (following cable conventional use). Bottom line its the installers option and what's on the truck.

 

Well the switch is in and it's working fine, thanks to everyone here, it was a little tight but I was able to the switches in.