Earthing Connection (Earthing / Grounding)
This is the safe joining of the panel body and the receiver enclosure to the protective conductor. It has two functions: providing personal safety by preventing touch voltage in the event of an insulation fault, and increasing the receiver's immunity by giving high-frequency noise a low-impedance return path.
The electrical safety side is clear: the conductive enclosure must carry the fault current over a path with resistance low enough to trip the protective device. The noise side, however, is about impedance; at high frequency what matters is not resistance but the inductance of the conductor. For that reason a long, thin earthing wire is a bad path for noise even if its measurement in ohms looks good.
- Practice: make earthing connections short and of large cross-section; clean off paint and the oxide layer and use serrated washers.
- Single point: use a common earthing busbar inside the panel; connect devices individually to the busbar rather than daisy-chaining them.
- Result: in a poorly earthed panel, inverter-sourced common mode noise circulates in the receiver circuit and shows up as intermittent response.
In panels using a receiver supplied with 220V AC (the SF100 and ST100 sets support this supply option), earthing must be evaluated together with control circuit separation.
The context in which this term is used: Wireless remote control installation: pairing, relays, safety