What is the disconnection time for a TT system protected by an RCD for circuits exceeding 32A?

The disconnection time for a TT system protected by a residual current device (RCD) is crucial for ensuring safety, especially in circuits that exceed 32A. The correct choice indicates a disconnection time of 0.2 seconds, which aligns with the requirements laid out in electrical safety standards.

In the context of TT systems, the disconnection time is necessary to minimize the risk of electric shock and ensure rapid isolation of the supply in the event of a fault. The 0.2-second requirement provides a balance between safety and practicality, ensuring that the RCD detects and responds adequately to an earth fault, disconnecting the supply quickly enough to prevent harm to users.

Standards and regulations typically specify that for non-lifesaving sectors, a maximum disconnection time of 0.2 seconds is adequate for final circuits above 32A. This quick disconnection helps to reduce the risk of serious injury or fatal accidents due to electric shock, particularly in domestic or wet environments where the risk is higher.

Understanding these requirements is essential for anyone involved in the installation and testing of electrical systems, as it directly impacts the safety and effectiveness of electrical installations.