Low voltage wiring ??

This electrical box was in the attic of a home I inspected today. It has 120v coming in and low voltage wiring going out. I could see low voltage wiring at some of the light switches that were a push button type. The lights appeared to be regular 120V fixtures and bulbs. I have never see this type setup in a house any help would be appreciated.





This is a low voltage switching system. The fixtures are 120 volts and are controlled by a relay from a low voltage switch. The low voltage should never enter the high voltage box. Look in the nec under class 1,2, & 3 wiring. By the way I went to northwest high school in indy

I went to northwest high school in indy.

That’s a GE RR7 low voltage lighting control system. Other than being missing the cover over the high voltage section, that’s about as neat as they come.

Looks like older cloth-covered wire on the left, 1st pic. A fair number of the low V switch wires and one or two of the high V wires are disconnected, not labeled or capped. It will be a nightmare for somebody, costly to troubleshoot and repair, antiquated switches. Hopefully there’s a cover?

John Kogel

I’d hate to see a bad one, what a rats nest :shock::wink:


this looks more like a commercial application. however, it sure looks like a home handy man job. you are correct that 120V is coming in but rest assure 120V is coming out. the compents you are looking at (the ones mounted to the side) are low voltage relays…which is just a glorified switch. the low voltage wiring that you see (approx 24V) is just controlling the relays.

hope this helps

I believe I read this system is from the sixties and normally has a remote system for all of the lights, near the front door.

Anyone have more insight, as I read about these a few years back.

Yeah, they seriously get much worse. They’re pretty easy to work on once you get a few simple things straight, but they’re typically always a rat’s nest.

Hey guys thanks for all the information on this lighting system.
The cover was laying next to the panel. There were a few disconnected low voltage wires, and one of the light fixtures in the basement would not turn off using the push switch. Everything else worked. This is what I like about this business, there is always something new to learn. What is the reason to install a system like this?

In commercial, there’s lots of reasons. Mainly because it makes it easier to move walls around, etc. Brand new systems just like this are being installed to this very day in commercial work. It also makes tying in building automation easier.

In resi, the main reason these were installed was to use the fancy low-voltage touch plate swtiches. Often, they only used the GE RS2-32 switches or an ordinary snap switch anyhow, so it was sort of a wasted effort.

Saves labor and copper

Re wired most of my first house with relays and am doing my existing home the same way

Relays are expensive unless you can get them for free

Takes a little time to design but this is the new and best way to go


Huh? I pay a little over 9 dollars for a GE RR7 relay.

That’s almost unbelievable. the cheapest I’ve been able to get them is $40.00 each, from GE Presco. Now that Presco is gone, I don’t know where I’ll get them.

I don’t know what to say. They’re on the shelf every day at my supply houses.