About Tubular Metal Sheathed Elements
Modern electric heating elements are manufactured to a design that renders them vulnerable to mechanical stress. The form of a modern cooker / oven element or washing machine, dishwasher heater element and some tumble dryer heaters is such that to attempt to bend it in any way at all would damage it beyond repair. The steel outer casing that is visible on all of these types of elements is just that, a casing, inside of which is a tube of epoxy or glass, it always used to be glass, but these days it is nearly always epoxy. Through the center of this tube runs the filament, the part that actually carries the electric current and heats up. The epoxy forms the insulation between the filament and the steel outer case which should always be connected to earth, or bonded to earth, this is so that it is impossible to get a electric shock from the outer casing of an element. If the epoxy insulator fractures because of mechanical stress, then electricity will leak from the live filament via the crack in the epoxy to the outer casing, which, because it is earthed, will cause a fuse to blow or a breaker to trip. If ELCB's are fitted in the consumer unit , these will react more quickly than a wired fuse and protect the appliance wether it be a cooker or washer or whatever, from further damage which can be caused by burning in the case of a wired fuse.
So, when replacing these items, it is extremely important to make sure that the element slides into its location in the appliance, whatever that is, without using any force, as to force could quite easily cause the epoxy insulation to crack, and once cracked the element is then absolutely useless, DUFF, scrap!