Tech Forum

X-10 was developed back in the '70's as the first consumer power line carrier (PLC) home automation product. While newer and more robust systems are available, X10 remains popular due to its simplicity and low cost. Back in the '70's we didn't have the plethora of wall warts, PC/printer/monitor power supplies or CFL & LED bulbs, all of which tend to either absorb X10 signals or put noise on the power line or both!

All of these signal suckers and/or noise generators can swamp the X10 signal resulting in the problems you're experiencing. There are filters, amplifier/repeaters and couplers to resolve these issues and, I'm happy to report that, after over 30 years of using X10, I've been able to maintain reliable operation even in fairly large homes.

Before adding any of the above devices, the trick is to identify the source(s) of the problem. At the time the intermittent problem began, think about what changed in the house. A new TV, computer, monitor or phone/tablet charger? Conversion to CFL or LED bulbs? If any of those get a yes, try removing them and testing. Plug-in filters will help.

Does the problem only happen at certain times? For example, when my in-ground incandescent pool light burnt out I replaced it with an LED bulb. When it was on it generated sufficient noise to render X10 useless to a number of locations. The solution was to add a hash choke in series between the switched wire from the X10 module and the light. Problem solved.

Another very important consideration is coupling from one side of the power line to the other. As we all know, residential service consists of two 120 volt legs (L1 & L2) from the street transformer to the electrical panel where roughly half the circuits are served by each leg. Electric ovens, water heaters and central A/C units are connected to both legs to provide 240 volt service. If an X10 controller is plugged into an outlet on L1 and the lamp module is plugged into an outlet on L2, the signal needs to find a bridge to get from one leg to the other. That bridge can be a 240 volt appliance, if it's on, or the street transformer itself - a long run that attenuates the signal.

The solution is to use a coupler at the electrical panel to provide a reliable path for the signal to reach every circuit. The very best solution that will overcome a multitude of problems is the installation of an XTB-IIR which is both a coupler and X-10 signal amplifier. It's available both as a kit or fully assembled from www.jvde.us. Building the kit is within the capabilities of most Nuts & Volts readers. That site offers a number of solutions and some great tutorials on X10 troubleshooting. I've been using both their site as a resource and their products for many years with great success.

I was having the same problem, with flakier and flakier performance. Some online research indicates that the problem is the result of the ever-increasing number of AC power line operated digital devices we use, each of which can feed noise back into the power line, potentially causing problems for other devices.

To prevent this, AC power line connections use a lot of filtering components (inductors and bypass capacitors) to prevent the digital noise from traveling back into the AC power line, but the bypass capacitors essentially short circuit the 120 kHz X-10 signals so they can't reach the devices they are intended to control. It's time to switch to Z-wave or one of the other radio-based control systems.

The X-10 protocol is passed at voltage zero, which makes it subject to other devices that operate at voltage zero. Did you add any electronic controls (lights, motor controller, etc) to your home? If you Google X-10 problems, you will get many possible solutions. Also, did you have any electrical work done at your house recently? If so look into the capacitor bridge to see if this helps. Also, look into possible noise sources (electric motors, SRC controls, etc.) as these may be producing sufficient noise to interfere with the X-10 signals.

You can get a "Powerline Signal Analyzer" but they cost $$$$. What I found was after many years of using X10, it became unusable due to interference. Do you have any UPSs at your location? They can be causing interference. Smarthome has wire-in filters that will help as well as plug in ones.