Fire risk of electric heater with combustible outer shell ITEM 7 Risks 1. Heater element 2. Electric connections by the installer 3. External fire In case of fire caused by external factor, the electric heater or bad connection is easily looked at as a possible cause. It is difficult to prove that the heater is not the cause. Therefore as basic requirement we prescribe to use incombustible shell (normally metal) A electric connection for 3kW (13A) heater is a likely source of fire in case of bad installation (by sparking, by wire overheat near connection, …) => in case of combustible material (topshell) risk for setting to fire The capacity of the heater is big in case of no water inside the tank. If not sufficient waterlevel (e.g. not enough filling, pump out too much for solar, trouble with heater switchoff…) risk of overheating & deformation of tank => in worst case finally fire if heater too close to shell. We can limit the risks by good design, but not reduce it to zero as basic policy we dont use combustible material as outer shell for electric heater applications (ref. Daikin standard GAA010-XE, class F1 appliance) Shell of combustible material 3 kW electric heater High t° High current