What does testing for 'earth continuity' verify?

Testing for 'earth continuity' specifically verifies that all exposed conductive parts are effectively earthed. This testing is crucial for safety in electrical installations because it ensures that, in the event of a fault, the electrical current has a low-resistance path to ground. This allows protective devices, such as fuses or circuit breakers, to operate correctly and disconnect the supply, reducing the risk of electric shock or fire.

When exposed conductive parts, which could become live due to a fault, are firmly connected to the earth system, it minimizes potential dangers to people and equipment. The test typically measures the continuity of the earth conductors throughout the electrical installation, confirming that any exposed metal parts are properly bonded and grounded.

In contrast, other options address different aspects of an electrical system. For instance, checking if devices are functioning correctly relates to operational integrity rather than earth continuity. Testing insulation resistance pertains to the integrity of the insulation surrounding conductors to prevent current leakage but does not directly verify the connection to earth. Lastly, evaluating the overall load capacity involves understanding how much load the system can handle, which is unrelated to the effectiveness of earthing. Thus, option B is the most accurate representation of the purpose of testing for earth continuity.