Electrical apparatus for switching or protecting electrical circuits, or for making connections to or in electrical circuits (for example, switches, relays, fuses, surge suppressors, plugs, sockets, lamp-holders and other connectors, junction boxes), for a voltage not exceeding 1,000 volts: connectors for optical fibres, optical fibre bundles or cables.
A: Relays are electrically operated switches that open and close the circuits by receiving electrical signals from outside sources. Some people may associate “relay” with a racing competition where members of the team take turns passing batons to complete the race.
B: Fuses are basic safety devices widely deployed in electrical circuits for excess current or overcurrent protection. If a stronger than expected current surges through, the fuse will blow and break the circuit, minimising heat damage and reducing the risk of electrocution or fire.