OT One more for the electrical experts...

I have an old house that I want to put a direct wired, in wall timer in for the outdoor lights. This would replace the old on/off switch that is in there now and allow me to have outdoor lights come on and off when I am not around. The wiring is a good 80 years old in the switch box and consists of two wires with heavy black insulation on them hooked to either side of a very old switch. Most all the timer switches I look at say they require a neutral wire. This puzzles me a little because I kinda assumed that all 110v AC systems had at a minimum a hot (black) and a neutral (white) wire, but then I have avoided working on the 80+ year old wiring in the past and have stuck with the modern stuff. My question is...do I have a neutral wire and how do I tell which one is the neutral wire?

I can tell you what I was thinking of trying. I was going to plug an extension cord with three wires into a known grounded outlet in the newer part of the house and run it into the old part of the house. Then I was going to use my VOM meter to check the two wires in the wall box using one lead to the box and the other to the ground on the extension cord. I was thinking the hot wire would read voltage and the neutral would not...or is that wrong headed?

Neither of the conductors attached to your switch is a neutral. One is hot, and the other is switched.

Switches don't need a neutral conductor (3-way and 4-way switches being the exception). But timers do need a neutral. In your case, the neutral conductor probably was run directly to the lights. Based on the age of your wiring, I'd probably run new Romex from the breaker panel to the timer/switch location, and new Romex from there to the lights.

Sounds like back in the day, they ran power into the switch, and power away from the switch, and only ran neutral to the light.

Your current wiring makes a large circle, from the box to the switch is a live wire, from the switch to the light is a switched wire, from the light back to the box is a neutral wire.

So no, you don?t have a neutral available for the timer.

Paul

Yup .... Tell him to just install an automatic one out side.

What you most likely have is the power and neutral wire (wire from the fuse box) is run to the light.
Then they run 2 wires from the light to the switch so you can turn on or off the power wire.
The modern way of doing that is to run the romex wire from the light to the switch and put black tape on the white wire to indicate it has been changed to a (black) power wire.

Today most run the wire from the fuse box to the switch.
I think both ways are still acceptable by code but do not quote me on that.

Very likely you have a feed( 2 wires, hot and neutral) to the switch box-- and a 2 wire from the switch box to the light/s. In this case the neutrals would be spliced in the box,thus you would have a neutral in the box. Useing your extension cord to give you a known - hot-ground and neutral is a good idea ( but if you get an outlet wired to the other hot leg you would read 220 volts hot to hot),, but Still would have a ground and neutral for testing. I would look into a new light fixture with a photocell and just leave the switch alone. Time clocks need to be reset several times a year due to longer /shorter days and are a PITA. joe

I would agree, much better to use photocell

With regards to timers versus photocells, we have some low voltage lighting that's on a timer. The timer is a constant aggravation; you have to reset it after a power outage, and I'm constantly fiddling with the settings as the seasons change.

I have a combination photocell and timer control I use for Christmas lighting. It comes on at dark, and you can adjust the on time from one hour up to all night. This one works off an outlet, but I'll bet there's something similar for permanent mounting.

Timers are fine with me. I have about a half dozen all thru the house. Most have memory save for power outages. Some even randomize the on/off time up to 30 minutes. The better ones can be programmed to adjust for seasons. I even have a mechanical timer that adjusts for seasonal changes. Photocells have been a problem for me. They come on during thunderstorms, flicker at dusk, burn thru bulbs faster than timers. I am not wanting dusk to dawn so a timer is for me. Not a fan of photocells.

That's as clear as it gets, thank you!

(quoted from post at 19:56:21 01/26/20) That's as clear as it gets, thank you!

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here are battery powered timers, full programmable that will exactly replace your simple switch.

I will see what I can find!

Like JMOR said, there are programmable timers that will work there.

They even have them with seasonal correction to change the time as the days change!

But, they are bulky, will fill a standard box to the max. That requires compressing the old wiring into a very tight area behind the switch.

If you have old cloth/rubber insulation, that could cause problems. Get the insulation to crumbling and this could turn into a much bigger job than anticipated!

Switch loop,hot&neutral go directly to the light, hot bypasses the light,goes down either the white or black on the 2 wire to the switch, goes back to the light on the other wire. Perfectly legal even today only they carry the neutral to the switch box by using a 3 wire then cap off the neutral at the switch. Then there is a neutral at the switch in case you need it at some point for specific lighting control.

Dave, to power a 120 VAC light requires 120 VAC and where's that located ???? its across the Hot and Neutral WELL DUH its 120 VAC Hot/Line to Neutral......

If done correctly ??? Its ONLY the Hot that gets switched, so the hot comes from the panel or fuse board,,,,,,,to and through a switch to open or close the series circuit,,,,,,,,,,to one side of the light,,,,,,,,,other side of the light is return wired to Neutral and there's the 120 VAC across the 120 volt light making it glow, another WELL DUH.

Iffffffffff there are only two wires in a simple switch box (One to switch input other to switch output) those would be the LIVE unSwitched Hot and the Switched Hot NOOOOOOOOOO NEUTRAL. The Neutral is wired to the other side of the light. The Neutral may or may not pass through the box where the switch is located en route to the light, but it obviously has to get to the light someway. At the light there must be a Hot (even if switched on or off) and Neutral to have 120 volts to power a 120 volt light.....

At the box where the light is wired there's a switched Hot and a Neutral, so when switch is closed the light is wired across Hot and Neutral for 120 volts and it shines, but if the switch is open there's no Hot and no 120 volts and no glow.

That's about as simple as I can make it. You asked for electrical "experts" but this is far below that level of expertise lol

Hope this helps, this is veryyyyyyyyyyyyyyyyy basic series electricity 101

John T

In a two wire switch box the switch leg is called a loop . The white gets fed that way up at the light the colors match black to black --white to white. That white of the switch loop [or switch leg is not a neutral wire. It is the feed to the switch [always feed the white to a switch for code] .

Well, you are right. That is as simple as the switched DC automotive stuff I worked on in my teens and today. I guess I was just used to the boxes in the modern part of the house where I usually find hot neutral and ground all present, but those may be different in other ways. Pretty easy. If I want a timer I have to find one that can be wired on the hot lead only else find a way to run a neutral wire to it. Pretty concerned about the size of a timer vs box though. Think I need a new idea.

Modern code would put you out of your misery as a neutral is required in a switch box Here :404.2 Switch connections Neutrals at switch new to code.

(quoted from post at 20:58:37 01/26/20) Like JMOR said, there are programmable timers that will work there.

They even have them with seasonal correction to change the time as the days change!

But, they are bulky, will fill a standard box to the max. That requires compressing the old wiring into a very tight area behind the switch.

If you have old cloth/rubber insulation, that could cause problems. Get the insulation to crumbling and this could turn into a much bigger job than anticipated!

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ot true of ALL....some fit in same spact as standard switch. I have a couple.

Dave,I have a home built in 1939. Rod and tube wiring. Before I rewired the house I discovered back then it was common to run power to light and the switch connected natural to turn the light on.

It was a shocking experience.

Be careful.

A timer well need power and neutral and some ground.

You'll have to power timer from an outlet and run the two wires to switch.

Or use LED outside light and leave it on 24/7.

Or use a timer to turn a lamp inside on and off.

George

If I go on Amazon about half the timers pictured do not require a neutral conductor.