RFI Earth protection for metal control panels
Many metal control panels connect 0Volt of the 12VDC supply to the case of the box, which in turn is connected to mains Earth.
Just imagine, the 0Volt to your PIR’s, Keypads and LIM’s is directly connected to all water pipes and electrical appliances in the street!
This can allow induced interference and lightning to feed back from Earth onto the 12Volt supply. Potentially, a nightmare scenario. Thankfully this problem can be overcome by fitting an ACT1166 High Frequency Earth Line Choke in series with the incoming mains Earth supply at the panel.
