What is a characteristic of MEN switchboards not found on standard distribution boards?

The characteristic that distinguishes MEN (Multiple Earthed Neutral) switchboards from standard distribution boards is the inclusion of a MEN link between the neutral and earth busbars. This MEN link is crucial for maintaining the safety and stability of the electrical system.

In a MEN system, the neutral is connected to the earth at multiple points throughout the supply network, which is integral in reducing the risk of electric shock and ensuring that fault currents have a safe path to ground. This configuration helps to minimize the voltage that can develop on the neutral during fault conditions, thus enhancing the overall safety of the electrical installation.

While the other options touch on various functionalities of electrical systems, they do not specifically capture the defining characteristic of MEN switchboards. For instance, having multiple circuits feeding into one supply can occur in various types of boards and doesn't uniquely characterize MEN switchboards. Similarly, while transformers can be involved in electrical distribution, they are not a requisite feature of MEN switchboards. Lastly, operating at higher voltage levels pertains to specific applications or installations rather than being an inherent trait of MEN switchboards.

Thus, the MEN link between the neutral and earth busbars is indeed the defining feature that sets MEN switchboards apart from standard distribution boards, ensuring increased safety and system stability