Electric circuit protection device having electrical parts ultrasonically joined using a brazing alloy

An electric circuit protection device comprising:

• an interruptable current path for interrupting current flow to a load including trip means for tripping the interruptable current path upon occurrence of a load fault;
• the interruptable current path comprising first and second electrically conductive parts that have been joined by ultrasonic welding to establish electric conductivity between them, one of the parts being an electric contact and the other of the parts being an electric contact carrier;
• the first part comprising non-alloying material;
• the second part comprising non-ferrous material;
• and a brazing material that has been acted upon by the ultrasonic welding to join the parts, the brazing material being selected to comprise at least two materials, one of the two materials being elemental copper, and the elemental copper being the largest single constituent of the brazing material.