Toasters should always be situated in a ventilated area. Toasters are often situated under kitchen cupboard, however the build up of heat the toaster causes can get trapped and pose a potential fire risk. Dualit recommends that toasters shouldn't be kept under cupboards or shelves, or when in use, the should be placed away from the cupboard.
Of course we realise that toasters will be stored under cupboards in a large number of homes. However we do ask that the toaster is pulled forward away from the cupboard when used though. A large proportion of the heat generated will go straight up and that is not good for your cupboards or under cupboard light fittings. Also, if a fire were to occur, those flames will be in direct contact with your cupboards if the toaster were still positioned underneath.