It is necessary to use an auxiliary relay, when switching pump motors or any loads that are not purely resistive. Compact Float Switch - WRAS Approved. WRAS approved float switches for use in water, industrial wastewater and sewage. The compact design makes them ideal for tighter spaces and they are unaffected by suspended solids or turbulent fluids. A round body design prevents solids building up on the boy and the switching unit is self cleaning that is impervious to humidity and condesation. Supplied with5m cable 10 Amp resistive switch contacts Available as N/O, N/C or C/O WRAS approved Adjustable counterweight