Questions about programmable switches

[Jennifer Murphy]

I need to replace a programmable light switch that was fried when a contractor plugged a compresser into the outlet it controls. I am trying to decide between these two Honeywell (Aube) programmable sunset/sunrise switches.

The 540A:

and the 740B:

The 540A is similar to the one I've had for 10 years that was fried:

It is designed to replace a standard toggle switch. The problem is that it can only handle 500 watts, which is why it was fried by the compressor motor.

It also requires a minimum load of 40 watts. Why is that? Why would it be damaged if the load were just a 25 watt bulb or a few 5 watt LED candelabras?

The newer model above (540A) has a little safety switch on the front to cut power to the switch while changing light bulbs to prevent a short.

The 740B has a limit of 1800 watts and no minimum, but it requires a neutral line. The receptacle where I want to put it has just three wires, which I think are the line (hot), the load (lights), and the ground (bare wire).

Is there any way to use the 740B in that receptacle?

[philoÂÂ]

If the load is under 40 watts, the unit will not get damaged, it simply may not work.

It looks like it just connects to a standard three prong receptacle and does not require any special wiring.

[Ralph Mowery]

It needs a minimal load. It will not be dammaged, but may not work. It is using the load on the end to get a sort of 'fake neutral'. The switch is getting the incomming power from the hot wire. As there is no neutral in the box, there must be a return path so a small ammount of return power goes through the load. Not enough power will go through it to light a 40 watt light bulb, but some power is. Probably enough to give you a shock if you touch the load side of the switch even if the light is 'off '.

[Jennifer Murphy]

Well, maybe not *special* wiring, but it does require a neutral, which I do not have in this old house. So my question is whether there is any way to use the 740A, which says it requires a neutral, in a receptacle that does not have a neutral. I assume the answer is "no", but I thought I'd ask.

[Jennifer Murphy]

OK. Thanks.

The other switch (the 740B) requires a neutral line, which I don't have in the wiring in this old house. I guess there is no way to use that switch in my situation, right?

[Ralph Mowery]

Not unless you can run a neutral wire to the switch.

[Retired]

Jennifer, you say "receptacle", but you mean "switch box".

Philo, the 740B replaces a standard light switch. It needs a neutral.

So if the Switch box onlys has 3 wires as Jennifer described ( the white is a switched "black", not a neutral), then a real neutral would need to be pulled in.

[jamesgang]

Nope. This is why some of the newer code requires neutrals at switch boxes.

How far is the outlet from the switch. If you can get a piece of 14/3 between the two you can add a neutral.

[Jennifer Murphy]

Or "junction box"? Or is that a closed box?

What's a receptacle? Or did I make that word up?

Thanks

[Jennifer Murphy]

OK, thanks.

[Jennifer Murphy]

The outlet is only about 10 feet from the switch box as the crow flies, but it goes under the porch or over the front door. The existing wiring is from the 1940s, at least some of it. One of the lines coming into that switch box is fabric covered. I think fishing a line would be impossible, at least for me.

But doesn't the neutral have to go back to the circuit breaker? That's clear at the back of the house.

[philoÂÂ]

OK sorry, I did not take a close look...I thought it was a plug-in device.

I guess I'd Google for a programmable switch with neutral not required

[jamesgang]

etween the two you can add a neutral.

Nope, the neutral can come from the outlet since it's the same circuit.

You could also run power from a closer source if you have an outlet closer to the switch. Run a new piece of 14/2 power from a nearby outlet to the s witch box. Then use the existing 14/2 line that is already going to the sw itched outlet as new switched power to it. Disconnect and cut back the ori ginal power line in the switched outlet but leave the end in the box.

[mroberds]

Intermatic makes a few in-wall timers that don't need a neutral and can switch up to 15 amps tungsten. I think these also have no minimum load. Looking at their Web site, the EI600 or ST01 may do what you want.

These tend to have batteries in them, which is why they can work without a netural - they don't need to draw power through the load. I had an older model Intermatic (circa 2000) that needed one AAA battery; a fresh alkaline would last about a year. The newer ones may have rechargeables.

I bought the one I had at either Lowe's or Home Depot.

Standard disclaimers apply: I don't get money or other consideration from any companies mentioned.

Matt Roberds

[Retired]

Generically it is a "switch box", like this:

but can contain a "receptacle", which is otherwise called an "outlet"

Yes, Junction boxes" are just that, where just cables are spliced together. Like this:

Here is a receptacle:

[Jennifer Murphy]

Thanks for the tutorial. Amateurs are notoriously lax with terminology. :-) I be more careful in the future. I got "short" and "open" mixed up a few weeks ago and I actually know the difference there.

[Jennifer Murphy]

There is an outlet about 3 feet away on the other side of the wall, but it's on a different circuit breaker. In any case, me trying to follow those instructions would be a surefire recipe for setting either my hair of the house on fire. I'll stick with the 550 switch that doesn't require a neutral and remember to keep anyone from plugging in a compressor. If I need the other switch, I'll hire an electrician.

Thanks for the help.

[Jennifer Murphy]

Thanks for that link. There are 4 that support sunset/sunrise programmability. They all have batteries, I think, and one has a rechargeable.

These look similar to the old Aube Ti034, which is the one I had that got cooked. I think the new Honeywell 550A has a much nicer UI. There's no flip up cover. Just a display and three buttons: left, right, and select. The left/right buttons display the sunset/sunrise times for today when not in menu mode.

[willshak]

How about a - programmable plug in light switch - ? Place the above between the dashes into Google search.

[Stormin Mormon]

So you have hot and ground, but no neutral? Man, that's some kind of messed up house. Every house I've seen had hot and neutral, but maybe not a ground.