Final answer:
A separated electrode or broken lead wire can cause a live wire to contact the appliance case, risking electric shock if not grounded. Proper grounding ensures the circuit breaker trips, preventing shock and indicating need for repair.
Step-by-step explanation:
An electrode becoming separated from the wire or a broken lead wire can cause a situation where the insulation of the wire becomes worn, leading the live/hot wire to come into direct contact with the metal case of an appliance. This condition is particularly dangerous because it can lead to electric shock if the earth/ground connection is broken, as the person may come into contact with the live metal case.
If the appliance is properly grounded, an electrical fault like this would typically cause the circuit breaker to trip, interrupting the electricity supply and signaling that the appliance needs repair to prevent the risk of electric shock.
Furthermore, issues such as electromagnetic induction can induce an emf on an appliance's case, leading to a shock hazard if the case is not properly grounded. The role of the ground connection is to maintain the case voltage near zero, preventing leakage current driven by the induced case emf from causing a shock.