Created by: Glen Zhu | Updated Date: January 16th, 2025
This article is based on IEC/EN standard.
Choosing the appropriate voltage for a surge protection device (SPD) is critical to ensuring effective protection of electrical systems and equipment. Here’s a step-by-step guide to help you select the correct SPD voltage:
Identify the nominal operating voltage of your electrical system (e.g., 220V, 230V, 380V).
Know the system configuration:
Single-phase (e.g., 230V), Three-phase (e.g., 380V), this is nominal AC voltage (Un).
Check the frequency (50Hz or 60Hz).
The surge protection device’s Uc (Maximum Continuous Operating Voltage) must be greater than or equal to the system’s nominal voltage to ensure the SPD can continuously handle the system voltage without degradation.
For example:
For a 230V system, choose an SPD with a Uc rating of at least 275V.
For a 400V system, an SPD with a Uc rating of at least 460V is typically required.
For PV solar systems such as 500Vdc, 600Vdc, 800Vdc, 1000V, 1200Vdc, 1500Vdc.
Case Study 1: Residential Power Supply Scenario
Mr. Wang has an air conditioner in his home with a rated voltage of 220V. He wants to install an SPD to protect his home appliances. Considering that residential power supply is typically single-phase 220V, Mr. Wang chose an SPD with a nominal voltage of 220V (Uc rating of at least 275V). This way, the SPD can effectively protect the air conditioner and other household appliances during grid fluctuations or lightning strikes.
Case Study 2: Factory Power Supply Scenario
A factory has a production line operating at three-phase 380V with multiple precision devices. To ensure the safe operation of the equipment, the factory decided to install SPDs. After consulting with professionals, the factory selected SPDs with a nominal voltage of 380V to cope with possible overvoltage and surge currents in the power grid.
Electrical systems experience temporary overvoltages due to faults or switching events. Ensure the SPD can handle these overvoltages without damage.
Check the SPD’s TOV rating (UT) to ensure it aligns with the expected temporary overvoltages in your system.
Determine which protection modes are required:
L-N (Line to Neutral) for single-phase systems.
L-L (Line to Line) and L-N/G (Line to Neutral/Ground) for three-phase systems.
Choose an SPD that covers all modes relevant to your system.
Ensure the SPD complies with relevant standards (e.g., IEC 61643-11, EN 61643-11).
Voltage ratings must match the standards’ specified ranges for the given system type.
Assess the potential surge energy and voltage levels in your region or application.
Choose SPDs with appropriate protection levels (e.g., Up – Voltage Protection Level) to ensure sensitive equipment is adequately protected.
Review the SPD’s datasheet for compatibility with your system voltage and grounding configuration.
Surge protective devcie SPD Manufacturer Wenzhou Arrester Electric Co., Ltd. may offer specific solutions tailored for different system voltages.
Example:
For a 230 three-phase system with a neutral, an SPD with the following characteristics might be appropriate:
Uc: 275V.
TOV withstand capability: Suitable for temporary overvoltages expected in your area.
Compliance with IEC 61643-11 or EN 61643-11.
Points to Note:
In conclusion, choosing the appropriate SPD voltage is crucial for ensuring the safe operation of electrical equipment.
If you have a specific system setup or requirements and want to how to choose SPD voltage, feel free to provide the details, and we can help refine the recommendation further!
LSP’s reliable surge protection devices (SPDs) are designed to meet the protection needs of installations against lightning and surges. Contact our Experts!
Copyright © 2010-2025 Wenzhou Arrester Electric Co., Ltd. All Rights Reserved. Privacy Policy