These electrodes are 2” long and assembled in molded plastic insulating shields. They suspend at desired levels in the well by means of suspension wire. A system ground return circuit is required from the indicated relay terminal to the liquid in order to complete the secondary circuit of relay. Connection should be made directly to uninsulated metal tank, or to metal pipe connected to tank below normal low liquid level. In wells, or insulated tanks, use an extra common electrode extending slightly below the longest operating electrode.