Powerline Carrier - What is a PLC System?

PLC stands for Powerline Carrier and is one of the oldest home automation standards in use. Powerline Carrier systems use existing home electrical wiring to transport commands to your home automation system devices. The most popular PLC in use is X10.

Why Use Powerline Systems?

Before powerline systems were used (and long before wireless home automation was available), automated systems required running dedicated wires for transporting control and command signals. It placed these systems beyond the reach of most homeowners because of the difficulty and home automation expense involved. When systems began using home wiring to transport command signals, home automation became a reality.

How Does PLC Work?

Powerline electricity or wall power operates at either 50 or 60 Hertz (Hz) depending on where you are in the world. Automation commands are typically sent in high frequency bursts (120 Khz for X10). The two frequencies coexist on the same wiring system without ever affecting each other. They act as if they never even see each other.

Problems Associated With PLC Systems

The biggest problem with PLC systems is distance limitations. The farther a signal has to travel, the more it will degrade or dampen. If the signal degrades too much, the target device will never recognize it. Several manufacturers have built boosters designed to overcome or lessen this limitation.

Another potential problem results from filters - devices such as power strips that are designed to take out high frequency noise. These filters are designed to protect equipment from damaging noise (like lightning bolt strikes) and can inadvertently filter out your normal automation command messages. If you are experiencing problems with a device responding correctly and you’re using a power strip, try bypassing the strip and plugging the device directly into the wall.