Control arrangement for immersion liquid heaters

An electric immersion water heater comprises a vessel with a heating element having cold tail ends extending individually through a side wall of the vessel. Temperature sensing elements sense temperature levels of an outer wall of the heating element outwardly of the vessel and are arranged to disconnect power to the element upon either a boil condition within the vessel occurring or upon sensing an elevated temperature indicative of dry or partially dry operation within the vessel. The heating element further including a jacket defining a space around the outer wall of a core part of the heating element within the vessel adjacent the vessel wall and arranged to fill with steam upon a boil condition occurring in the vessel during normal operation.