Electrical Wiring in the Home/low voltage switches


Herb wrote at 2006-09-04 00:31:47

I installed a low voltage control system in my home in 1960.  I still enjoy the advantages of this system although I do have problems purchasing replacement parts. My system is based upon a 30 Volt supply and old GE switches comboned with Remcon relays.  The relays are located in a utility box mounted on my power panel.  Lots of flexability in controling lighting! I plan to continue the use of this system until I am forced to replace it.  Just wish that I could purchase replacement parts.

If I can be of any technical assistance, feel free to contact me.  

Mark Stailey wrote at 2008-12-03 04:49:45

My father in law also installed this type of system in their "new" home in the early 60's as well. The old man now has Alzheimer's and doesn't have a clue. It's really quite sad. Nonetheless you say that you have problems purchasing replacement parts. I have found it to be virtually impossible. I really don't know where to start. You also say that you plan to continue to use this system until you are forced to replace it. With what? I can only think of rewiring with conventional wiring. And in the trilevel design that I'm dealing with it's impossible to get to everything. Any ideas?

Thanks Herb,

Mark Stailey

DON GREER wrote at 2010-01-03 21:30:35
Low voltage relays, whether the old style mechanical relays or the new style that are solid state, both work the same way.  The relay controls 120 volts, your so called hot wire, across a single switch contact that when activated by the wall switch can activate or deactivate a device of choice.  

In other words, when you press the lows voltage switch on the wall to put a light (or any other electrical device) the low voltage relay is activated, which in turn makes an internal electrical contact that sends power to the light.  The reason for low voltage is so that any number of switches in any number of locations can control the same device without the need for 14 gauge hard wiring.  This is done by running smaller 18 gauge (depending upon electrical code in your area) low voltage wire to the relay.  The low voltage is usually 14 volts of alternating current.

If you look at the relay wiring itself you will find that the house neutrals (white wires) are usually connected together and are no part of the relay circuit.  The relay does not connect to any part of the 120 volt house neutral circuit.  A 120 volt power wire (black or red) from the circuit breaker should run to one of the two heavy wires on the relay.  The other heavy wire will run to the device to be controlled.  The smaller wires on the relay are low voltage.  

There will be a 24 volt transformer in your box somewhere that provides the voltage to operate the relay.  The neutral from the low voltage transformer goes to one side of the low voltage relay (the coil in the mechanical relays; the solid state relays work the same way).  The low voltage power wire goes out to the wall switches and then back to the other side of the relay.  When you press the low voltage wall switch (it acts like a start button) it sends power to activate the relay.  When you press the off portion of the low voltage wall switch (it acts like a stop button) it breaks or opens the low voltage circuit, the relay thereby opens the 120 volt connection internally and the device is turned off.

Low voltage is a simple, cost effective and safe way to wire devices that is used extensively in industry and housing today.  Donít be afraid of it.  It is really wiring 101.  

Starrman wrote at 2012-03-25 00:10:50
They still use Low Volt switching in many tall buildings but they don't use the relays themselves anymore ..... Lithonia and GE are the ones I've seen ...they are all programmed  electronics linked from floor to floor etc (still use 3/18 bell wire thow) ... (for after hour auto shut down / energy savings etc)  and most don't use those tiny switches anymore either ... they use full size momentary Single pole double throw switches  

Henry wrote at 2014-05-04 03:06:45
GE still makes relays and switches for their Low Voltage Control System and there is a Yahoo Group named GELV that has a lot of  helpful members and information to help you keep your system going.  The link is shown below:



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Electrical Wiring in the Home

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Rick Miell


Past County electrical inspector, hold St. of Colorado Master license, will try to answer any electrical question with Code related answers.


State of Colorado Master Electrician. Past County Electricial Inspector (15 years)

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