What is the preferred maximum length of a connection between SPDs and the MET or connecting conductor bar?

The preferred maximum length of a connection between Surge Protective Devices (SPDs) and the Main Earthing Terminal (MET) or connecting conductor bar is indeed 0.5 meters. Keeping this connection as short as possible is vital for minimizing the inductance and providing an effective path for surge currents. A shorter connection length reduces the risk of voltage spikes that can occur due to inductance during a surge event. It ensures that the SPD can react swiftly to transient overvoltages while maintaining the protection of the connected electrical system.

In professional practice, recommendations and regulations often emphasize reducing the distance to enhance the effectiveness of surge protection and ensure compliance with safety standards. This focus on a short connection helps to ensure optimal performance in protecting sensitive equipment from surges that could lead to equipment damage or failures.