Surge power distribution box selected

Choose a surge power distribution box by matching SPD type, voltage rating, current capacity, and installation location to your system requirements.

Key Considerations for Selection

1. SPD Type and Placement

• Type 1 SPDs: Installed at the main distribution board to handle high-energy lightning currents, typically at the boundary between external and internal zones (LPZ 0B to LPZ 1) ( ).
• Type 2 SPDs: Installed downstream in sub-distribution boards to reduce residual surge energy, suitable for most home and commercial boxes ( ).
• Type 3 SPDs: Installed near sensitive equipment for fine protection; they have limited discharge capacity and require upstream Type 1 or 2 protection ( ).

2. Electrical Ratings

• Voltage Protection Level (Up): Maximum residual voltage the SPD allows; lower Up is better for sensitive electronics ( ).
• Nominal System Voltage (Un): SPD should match the system voltage (e.g., 230V single-phase or 400V three-phase) ( ).
• Maximum Discharge Current (In): SPD must safely discharge expected surge currents repeatedly; higher In is needed for areas with frequent surges ( ).

3. Physical and Installation Requirements

• Enclosure Fit: Ensure the SPD fits the distribution box, whether surface-mounted or DIN-rail mounted ( ).
• IP Rating: Choose IP20/IP30 for indoor use; IP65/IP67 for harsh or outdoor environments ( ).
• Spacing: Maintain recommended distances between SPDs and between SPDs and equipment (e.g., 5–10 meters for voltage-limiting SPDs) ( ).
• Accessibility: Pluggable modules allow easy replacement without disconnecting wiring ( ).

4. Compliance and Safety

• Follow national electrical codes and standards such as EN 62305-2 for lightning protection risk assessment ( ).
• Ensure the SPD's breaking capacity exceeds the maximum short-circuit current in the system ( ).
• Test SPDs periodically (every six months) for signs of wear or damage ( ).

5. Additional Tips

• Use multiple SPDs for layered protection if the first-level SPD cannot handle all surges ( ).
• Consider both common-mode and differential-mode protection depending on system requirements ( ).
• For residential projects, Type 2 SPDs after the main breaker are generally sufficient ( ).

By carefully evaluating SPD type, electrical ratings, enclosure fit, and compliance with standards, you can select a surge power distribution box that effectively protects your electrical system and sensitive equipment from voltage spikes and lightning-induced surges.