The mains decoupler used to reduce stress caused by electric alternating fields from the power supply.
The electricity supply lines in our buildings produce magnetic and electric alternating fields. While the magnetic fields “disappear” when the devices we used are switched off, the electric fields remain in the whole power supply system.
This is where the mains decoupler comes in: it is installed into the fuse box and automatically separates the circuit it is intended for from the network as soon as the last consumer is switched off. As soon as a device is turned back on, the mains decoupler recognizes this and automatically turns the supply voltage back on without any delay.
That way, after you turn off your bedside lamp, you can sleep in a neutral EMF environment (from electricity lines) in your bedroom, meaning that the electric cables in the wall just behind your head will not produce any electric field while you sleep.