To protect the electrical circuits used blade-type fuses, the color of which corresponds to a current protection fuse. The fuse is determined by the presence of the wire conductor connecting contacts of the fuse. To replace a failed fuse switch off the corresponding electric chain, take a safety lock from a nest tweezers. If newly installed fuses instantly fails at pressure giving, check the protected circuit. If the safety lock protects some chains, they must be connected in turn to a blown fuse on the defective circuit.