There are two types of lightning protection modules used with SIGNAL irrigation controllers.
All controllers are supplied with a Surge Protector (SD-SP). This is installed at the controller itself, and as close as possible to the earthing stake.
For best results, flat braided cable should be used to connect to an earth stake of at least 2 metre length, with a resistance to earth of 10 Ohms or less.
For two-wire systems, there is the option to also install Surge Arrestors (SD-SA) along the two-wire line every 350 meters, or 16 valves. Surge arrestors need to be installed using only approved waterproof connectors for two-wire cable joints. All joints should be located in access pit / valve box.