Lightweight electric fuse

An electric fuse 10 comprises two terminals 12,14 attached to a housing having an outer wall 22 and an inner wall 24 defining an internal space 26, and at least one fusible element 16 having two ends each connected to a respective terminal. The housing is made from a plastics material such as a thermally conductive resin or polyphenylene sulphide (PPS) and comprises at least one cooling channel 28 between the inner wall and outer wall. The housing may be made of two parts: a 'case' 18 and a 'cover' 20 which may attach to each other through a tongue and groove arrangement. The housing may comprise an opening 30 for filling an insulating material, such as sand, into the internal space. A protector 32 may be insertable between the inner wall and the fusible element(s) and may be made from an arc-retardant and/or heat carrying material such as ceramics. The protector may comprise a tube for holding a fusible element. The cooling channel may extend nearly in parallel to the fusible element and at least partly over the extension of the housing between the terminals. The use of a plastics rather than ceramic housing reduces weight, and the cooling channels help remove heat from the central region of the fuse to improve thermal balance.