Control for Lamp Circuit Using Low-voltage Push-on/off Button

Nehmo

Oct 15, 2011
7
I'm adding an additional light to a room with 2 entrances in an old house. Instead of using the common 120V 3-way SPDT switches to control the light fixture from 2 points, I'd like to use a relay (or something electronic) directly connected to the load of the light, and I'd like to run low voltage wires to push buttons located near the doors of the room. These will control the light by one press = on (if the light is already off), and the following press will = the alternate condition, the light going off.

The should be a commercially available relay (some kind of latching relay, perhaps) product with the circuit. Can anybody recommend something? Or, perhaps I could put together the components myself. Does anybody have a schematic of something along these lines?

Bluejets

Oct 5, 2014
6,189
Low voltage part ie flip flop with switches, some form of lv supply and relay should be straightforward.
Eventually you will have to engage a licenced electrician to install a feed and make certain the mains and low voltage are adequetly isolated from eachother.
The latter I would imagine, would be the same overall, if not more than the original 2 way concept and getting in the lecky.

Tha fios agaibh

Aug 11, 2014
2,249
I don't know where your located, but this a violation of American electrical codes because its not a listed device.
Some jurisdictions may grant special permission if it's limited energy and you can show that there isn't a UL listed alternative.
But most electrical inspectors wouldn't allow it.

Bluejets

Oct 5, 2014
6,189
I don't know where your located, but this a violation of American electrical codes because its not a listed device.
Some jurisdictions may grant special permission if it's limited energy and you can show that there isn't a UL listed alternative.
But most electrical inspectors wouldn't allow it.
Whose location?

Aug 11, 2014
2,249

Irv

Jun 7, 2017
112
First problem might be cost. GE still makes low-voltage UL approved relays. $35 and up. Plus a transformer$80+ !! Then you'd need an *old* electrician who can install it without freaking out. (AKA knows what he/she is doing)

The above is to keep from burning down your house while invalidating your insurance.

The rest (low voltage) you could do yourself legally in most places. You'd have to check that.

An alternative would be to buy a wifi lightbulb and control it from a cellphone. Overly complex solution, for sure, but much cheaper with no worries about safety / legality.

Tha fios agaibh

Aug 11, 2014
2,249
First problem might be cost. GE still makes low-voltage UL approved relays. $35 and up. Plus a transformer$80+ !! Then you'd need an *old* electrician who can install it without freaking out. (AKA knows what he/she is doing)
Actually Rib relays (relay in box) and class 2 power supplies are rather inexpensive.

The problem isn't that the electrician freaks out, it's that they don't want to do the work only to have the electrical inspector red tag it for violating article 110 of the Nec.
You could call the local authority having jurisdiction and ask if they'll allow it, or pay big money and have a field evaluation done by UL in order to satisfy the listing requirements.
Probably not worth the trouble.

BobK

Jan 5, 2010
7,682
Or, you could avoid all of these problems by using X10 components you can install yourself.

Bob

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