ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Tuesday, April 9, 1996 TAG: 9604100021
SECTION: EXTRA PAGE: 3 EDITION: METRO
COLUMN: At Home With Technology
SOURCE: DAVID BUTLER
Q: I use an inexpensive "power line carrier" timer to control several lights around the house. I decided to expand my system but haven't been able to find the right modules. For example, I'd like to use my timer to control a ceiling fan. Are non-dim wall-switch modules available?
A: Power line carrier (PLC) technology has become the de-facto standard for ``plug and play'' home control. Although PLC-compatible products are widely available through retail outlets, selection is usually limited to a handful of basic controllers and modules.
A more extensive line of PLC products is distributed through electrical supply houses, home control dealers and mail order catalogs. Prices for "trade-line" modules are higher than for retail versions.
As you discovered, the retail wall-switch module is essentially an electronic dimmer. Electronic dimmers create voltage distortions that can quickly damage a fan motor or other non-lighting load. Damage can occur even while the dimmer is operating at full intensity.
The popular plug-in appliance module or the wall receptacle module can control non-lighting loads. These modules rely on a mechanical relay to interrupt the flow of current instead of a dimmer - not much help since your ceiling fan doesn't have a plug!
The good news: Trade-line PLC modules are available that can handle almost any load or circuit - dimming or non-dimming, 120 or 240 volts (double-pole), three- or four-way. Assuming your fan is wired to a standard wall switch, simply replace your old switch with a non-dim PLC version.
And now, the bad news: Non-dimmable wall-switch modules won't respond to PLC signals unless they connect to the "neutral" wire. (In household wiring practice, neutral is usually the white wire.) OK, I realize this is a bit technical, but bear with me.
As it turns out, mechanical wall switches don't connect to neutral. In practice, this means the neutral wire is unlikely to pass through an electrical box that holds a wall switch. Unfortunately, without the neutral, there's no path for PLC control signals. Incandescent wall-switch modules (e.g., those with dimmers) get around this problem by using the light bulb filament as a signal path to neutral.
What if there isn't a neutral wire at the switch? What about fans with wall-mounted speed controls? What if the fan doesn't even have a wall switch? In each case, you could hire an electrician to add the necessary wiring for a PLC wall-switch module. Or, you could install an "in-line" fixture module.
The fixture module is designed to fit inside the electrical box that supports the fixture - one location that's sure to have a neutral. It connects directly to the wires that supply power to the fixture. As with non-dim wall-switch modules, the fixture module is available through trade-line distributors.
Other trade-line products include a wall-switch module with local dim control and dim-level memory. Note that the retail version can only be dimmed remotely from a PLC controller. There's also a special "inductive" dimmer module for low-voltage lights. This module can also be used as a continuously variable speed control for a ceiling fan, though it's likely to cause an audible hum.
To receive a comprehensive list of companies that produce PLC home control products, please send $1.50 and a self-addressed envelope to David Butler F-607, Department TWN, 14713 Pleasant Hill Road, Charlotte, N.C. 28278-7927. The list includes descriptions and sources for trade-line PLC modules. You'll also receive information on power line carrier controllers and software for personal computers.
In case you were wondering ... Power line carrier (PLC) technology makes it possible to operate lights and appliances without special wiring. Timers and other PLC controllers transmit coded signals (on/off/dim) over ordinary household electrical wiring. Controlled lights and appliances connect to plug-in or wired-in receiver modules - each identified by a user-selectable unit number. The unit number ensures that only the intended module responds to a command.
LENGTH: Medium: 78 lines ILLUSTRATION: GRAPHIC: Here are two methods of connecting a permanentby CNBfixture, such as a ceiling fan, to a power line carrier
remote-control system.