first purchased our home, I was intrigued with the odd looking wall
switches. They were momentary rocker switches, so I surmised that they were
operating relays via low voltage. When an electrician was in to do some
work, he volunteered some sketchy information about the odd switches, and
something about how “that system” represented guaranteed employment for his
profession. I sought further information and found this article in
Better Homes & Gardens Decorating Book, 1961 edition, which explains how
it looked forty years ago:
Low voltage switching
adds convenience to your home.
An outstanding advance in electrical systems is low-voltage switching. You
may have heard of it as “remote control,” “l-v” (for low voltage), or
Some folks have added a little confusion by calling this system low-voltage
“wiring” instead of switching. True, it uses low-voltage “door bell” wire
leading from switches. But all the lights and outlets still feed from the
usual 115-volt current.
How does it work?
You can compare low-voltage switching with your automobile’s electrical
system. When you press a car’s starter, you’re not working directly with the
strong surge of electricity needed to operate the starter motor. A spark of
current travels from dashboard to a magnetic relay. This commands the
battery’s full punch to start the engine.
In a house, you press a touch-plate switch and a small (24-volt) flash of
current notifies a relay (grouped near service entrance, or, in some
systems, right at the fixture). A magnetic switch then opens, and the full
115-volt current is sent to do whatever task you have in mind.
Simple as that! But why is this better than the standard method of
switching? The one where a wall switch operates as a gate through which the
actual current flows?
With low-voltage switching, a dangerous shock at the switching point is no
longer possible. This means low-voltage switching is a natural for outdoor
use, the laundry, kitchen, workshop, or other areas where the shock’s more
of a potential hazard.
The smaller current load allows much smaller wire than in a conventional
system. This wire is easy to drag through a wall; it requires no rigid
conduit or bulky bindings and insulators.
What’s the biggest
The thing that makes this system so popular in today’s sprawled out “ranch
style” houses is its remote and multi-control characteristics. To control
one light from two points, conventionally, you have to double heavy,
expensive 115-volt wire running between the switches. To add a third
control gets costly and complicated. Remote control over a great distance
shoots cost up in a hurry when you’re stringing out doubled Number-12 wire,
With low-voltage switching—where one magnetic relay works the light—it’s no
trick to have a third or fourth control to every one of the lights. And
with the cost of low-voltage wire and switches less, there’s no reason why
you can’t enjoy complete mastery of your home’s lighting. This means an end
to groping into a dark room looking for a switch.
Costs of low-voltage or a conventional system are about the same in a small
house—or in a house over 2,000 square feet (where long halls and large rooms
necessitate multi-switching). Costs for low-voltage switching in a medium
size house are slightly more than for conventional.
then. Flip forward forty years. Most of the frequently used switches in
our house have been replaced over time—for good reason. Those
aforementioned inexpensive wall switches were not only inexpensive, they
were cheap. The style in this house have a switch button that tends to get
hung up under the mounting plate, and sit so low relative to the cover plate
that the button has to be pushed way below the surface of the cover plate.
Aside from that, they have to be pressed down and held for a moment while
the relay actuates. And some are just plain temperamental and need to be
pressed a few times to work, which I suppose is more a sign of a failing
relay . Speaking of which... in this house they
are distributed, not nicely ganged at a central control panel. In a
distributed system, the relay is located in each individual electrical
box, so often a little difficult to get to. Replacement parts are
available though may take extensive hunting around.
have changed. GFI receptacles have solved the wet/exposed area safety
issue, and in fact are now required by code. Two- and three- way
switches are commonplace. Unlike many of the historical and occasionally
quaint features of our vintage homes, L-V switching retains no charm. No
tough choices here when it comes to upgrading electrical devices. Make mine
One style of L-V wall switch. The control is a momentary rocker. Press one
side and the relay is activated to turn a light one; press the other side
and the relay shuts the light off. The cover plate is made of fragile
styrene, with a gold –printed paper panel pressed in from the back side.
The bare switch component on its mounting bracket, front and back C.
Note the small gauge doorbell wire.
Another style wall switch that has a huge rocker switch for its entire face.
These probably operated a lot better, and certainly looked neater. Made of
phenolic, so they are very stable and durable. They even look
something like today’s Decora style switches.
The relay that actually does the switching. Signal from the wall
switch comes in
on the small gauge wires; line voltage goes to the light on the large gauge
assembly of a relay in an electrical box; in this case, a ceiling light
fixture. Here, replacing a failed relay would not be so difficult as
it could be fished out through the device side of the box.
Touch-Plate 5000-series wall switches, currently available. Yes,
that's right-- its not too late to get an LV system for your home!
These are simple momentary switches (push on / push off) so may not be
compatible with older systems that have rockers that must be pressed on the
on side or the off side.
Even the modern equivalents seem to be sort of hard to find. I
point seekers to Dale Electric which has a large online catalog. Go
to: www.dale-electric.com and
search on "low voltage relay" or "low voltage switch. Try these
links to get to the exact topics within the Dale catalog :
Do you have a
home with L-V relays ganged at a central location? I’d like to take a photo
and add it to this page.