Care and Feeding of My 1950s Low Voltage Relay Lighting System
May 15, 2006 6:02 PM Subscribe
1950s era Low Voltage Relay Lighting - My new home has a system, and I'm not sure what to do if it ever breaks. Are there any good resources for parts out there? Any good discussions on these systems? Books I should pick up?
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These are known as "Touch Plate" systems. Each press of the light switch causes the light or outlet to toggle on or off. The system has a central "transverter" which is just a transformer that converts the 120 volts to 28 volts. The 28 volts is distributed to each switch. The switch causes a relay to turn on of off the high voltage current to the light fixture. There is one relay for each switch.
The relays are all centrally located in a relay box, usually in a closet. If you haven't found the relay box yet, have someone turn a switch on and off while you poke around the house listening for a mechanical click. The clicks should lead you to the relay box. The transverter may be located in the relay box or else near the main circuit breaker box.
The transverter and relays usually last forever. The most common failure is a stuck wall switch, either because the contacts have worn or else because of a sloppy paint job gumming up the touch plate. Since the 28 volt side of the control circuit is connected in parallel to all touch plates, a single stuck plate will cause all switches in the house to malfunction. You will have to find the stuck touch plate.
Since the switches only carry 28 volts, they are safe to work on. Disclaimer, you should first check with a volt meter to make sure that there is only 28 volts on the switch.
Check out Touch Plate. Here is a trouble shooting guide. And parts list.
posted by JackFlash at 8:00 PM on May 15, 2006