Today for the first time in my life i came accross a house that was low voltage switched. Never have I seen this before. All switching was done thru low voltage wireing to a large relay box in the attic. Low voltage actuated the relays and 120 volts went out.At first I did not know what to belive. I thought the wireing somehow was connected to bell wire. I was wrong. just wondoring how many of you have run accross this and when was it popular if ever? I was really spooked by this as I never even heard of this? Comments?

Well, your time estimate is a bit off.

Low voltage wiring had a brief 'moment in the sun' in the mid-60's ... as the latest word in safety. It was particularly aimed at bath and kitchen uses. It was believed to greatly reduce the risk of electrical shock.

Just as it was getting going, along came the GFI.

Steve, my neighbor's house across the street from me was built in either '58 or '59 and the entire house has a low voltage lighting control system. My neighbor was building the house himself and was talked into the system as being the newest and greatest thing.

steve

the last time I saw that as a new install was in '76
it was used a lot in office buildings for switching 277v lighting

FWIW Pass & Seymour still makes the stuff

We installed a ton of it when I helped my brother build his house in '93. It kept us from needing several 3 & 4 ways and allowed us to do some On/Off/Time delay Off switching for outdoor lighting. Our relay panel went in the basement though.
Joe

I still got a bunch of replacement relay's for those.

"Touch Plate" lighting controls have been around since 1946. They were the state of the art for '50s era homes.
I installed them up into the early '80s.

They're still around, and still make new relays for the original design controls.

Check it out

In the late sixties and seventies low voltage switching was popular in very high end housing because it could be used top control multiple areas or zones. One low voltage switch could be used to start a sequential relay control motor so that as it slowly turned, it would activate relay contacts that were in parallel with the normally open switches that controlled a specific room or light. I serviced a large estate in the mid seventies that had an extensive low voltage switching system. From a touch of three switches next to their bed, the home owner would start a sequence that would turn on every interior and exterior light in their home and on their entire estate. These were some very high profile people and they didn’t mind spending the money as they felt they needed the extra security. The system was comprised of at least 4 motorized zone controllers and at least 100 relays. Quite impressive for the day.

Regards………….Elec N Spec

I remember a General Electric LV control system which was installed in a church built in 1970. The system was used to control the sanctuary lighting. There were 12 circuits, controlled from two locations - the pulpit, and a control room at the rear of the sanctuary (which also contained the Relay enclosure, two breaker panels, 480/277 - 208/120 transformers, dimmers, and the sound system mixer/amplifiers). The controllers had two 12-position dials, one for ON and one for OFF. turn the dial to a circuit number and push to operate - or else hold the dial in and turn it to operate a number of circuits quickly.

Quite a durable system. It still works perfectly, although the sound system had to have a major re-build - lots of hum and noise from all that power equipment nearby.

Mike (mamills)

What would be a complex switching scheme otherwise, becomes a piece-o-cake in a low voltage system. Switching any number of loads on and/or off becomes a simple matter of using a diode matrix. The only limiting factor would be the additive currents of relay coils, exceeding the ampacity of switches or the power supply.

I remember building a couple of PCBs for outdoor lighting control. A tap on the off button caused a several minute off-delay while holding the button for 3 seconds turned the lights off without further delay. I could have just as easily put in a control to turn the same lights on if the dog barked. On a more practical note, those relay boards they sell that connect to a parallel printer port, and a few more diodes, would have added computer control to the matrix. Once you have 3 wires into a 2 switch combo, control possibilities are limited by your imagination instead of the number of conductors.
Joe

Mike now you mention GE low voltage system switching devices yeah i do rember them very well most of the time it work pretty good but when the relay go bad it get crappy espcally with the power supply

Merci , Marc

Yes, thank god they still make those power supplies. When those start to go the system really starts to freak out and behave strangely. I also think for the price the lite-touch switches aren't as durable as they could be, compared to a regular old average quality line voltage switch. That open design lets junk get between the contacts, and it seems like people unfamiliar with lite touch don't "get" that you don't need to hammer the touchpad for the light to come on. I wouldn't want to have one of these systems in a rental property.

Freaking NIGHTMARE they are.

You have to troubleshoot TWO systems and every 50's system I've seen (in AZ) has the relays in the ATTIC!!...and it is always a total rat's nest!!!

Sometimes the relays are DC.

You can't simply add a dimmer.

You have to hunt for parts.

I have seen a few CURRENT systems. I can't believe that someone would think this is a good idea. Just because you CAN do something doesn't mean you SHOULD.

I have torn out a few of these systems and replaced them with standard wiring.

Relay switched systems are pretty common in Europe, I'm pretty surprised they don't exist in NZ. Realys can be mounted in a box or in a DIN rail panel and are either 230V or 12V AC operated (230V being far more common). Most "modern" electricians use those systems where ever they have to control lights from more than 2 points. If you want a dimmer you have to switch out the relay, the switches stay the same.
Everything works with simple bell buttons. One push: on. Second push: off. Dimming: push: switch to previously set state. Hold: dim from low to full until button is released. There are both mechanic relays and electronic flip-flops. I don't like either of them because I think it makes the wiring a mess if you have to run every light feed back to the panel and the mechanic relays make quite some noise. And don't even ask me about adding anything electronic to 230V house wiring

Perhaps someone who has worked with these LV systems can elighten me here. Regarding the system I described for the church, I remember that two of the twelve circuits controlled eight enormous ceiling chandeliers. I don't know the actual load of each chandelier, but I would guess them to be roughly 1700-1800 watts each, and four chandeliers were switched by a single LV circuit. I would assume that the LV side of the relays could be wired in parallel (i.e. one LV circuit could operate, in this case, four relays simultaneously), since one of the breaker panels contained an individual 20a breaker for each chandelier, plus numerous breakers for other lights (pulpit, chancel, choir, baptistry, wall washers, etc.).

Were these relays available as multi-pole units, or of larger power-handling capacity?

Mike (mamills)

The last one with relays that we worked at was from the 60's/ 70's era, complete with an intercom system with built-in AM radio throughout. We call it the Brady Bunch House.

Thankks for all the feedback. The guy I work for part time ( He is in his 60s) knew exactley what this was. Bet its the last time he sends me out to look at something for him.Now that I have a little idea what it is its time for some more reading and studying. Thanks again gang you guys (and gals) are the best.
Steve

First two houses I wired back in 1954 both had GE LV wiring with the relays located in the ceiling boxes. One of the useful features was a central control that the HO wanted was located in the master BR so that he could turn on most of the lights inside and out side from his bed with a twist of the control. The system seemed to be a good idea but we never did any more.

In troubleshooting old lv lighting systems, the major problem I encounter is not failed relays. It is the twisted bell wire used for the switch legs to the relays. That red/white twisted bell wire that they used a lot of for that and doorbell wiring eventually degrades and cracks apart shorting out the secondary circuit of the transformer.