Dimming - What is Power Line Communication (PLC)?

Power Line Communication (PLC) is a tone signal technology that is used by energy suppliers to remotely control large groups of electricity consumers. These consumers include street lighting, or electricity meters with day/night schemes, or electric boilers that are regulated by PLC. This technology uses tone signals that are grafted onto the sinewave alternating current of the grid by the regional electricity network operator. These PLC signals are visible during measurements as a ripple on top of the sinewave alternating current. The amplitude of this ripple varies from 1% to over 5% of the size of the sinewave alternating current.

PLC signals influences how dimmers and the connected light sources operate. The bigger the amplitude of the ripple, the greater the negative impact on the dimmer and the light source. The lighting flickers, or the light intensity fluctuates when it is dimmed. This has a negative effect on the comfort in the room. The fluctuation hardly ever occurs with maximum light intensity. Sometimes there is an audible buzz or humming. It is primarily LED lamps that suffer from PLC, and some people find the effects to be very annoying. Very occasionally, this issue also affects traditional lighting such as incandescent lamps and halogen lamps. With traditional lighting, a user will rarely or never notice it due to the longer glowing time of the wire in the lamp.