Do you need surge protection in your panel? Here's what you need to know.

As a manufacturer of control panels, we frequently get asked - do we need surge protection in our control panel? The short answer is: in most cases, yes. But let's dive deeper into why and when you might need it.

First, let's define what we mean by a surge. A surge, also known as a transient voltage, is a brief spike in voltage that can occur in electrical systems. Your supply voltage is not perfectly steady, it naturally fluctuates, and occasional spikes can still occur due to minor load changes or local disturbances. These surges, while brief, can damage sensitive components in your control panel.

Control panels often have sensitive electronic components in such as PLCs, HMIs and network switches. These components are designed to operate at specific voltage levels, typically 24V DC or 230V/400V AC in the UK. A surge can easily exceed these levels, leading to component damage and the consequences of surge damage can be severe. Equipment failure, data loss or corruption, safety system failures, costly repairs or replacements. Suddenly the cost of a surge protector is trivial compared to the expense it can save.

The way surge protectors fundamentally work is by diverting excess voltage to earth, type 2 usually triggers at 1.5kV to 2.5kV, type 3 triggers around 1.2kV. So anything above those voltages gets dumped to earth. One of the most well know types of surge is a lightening strike

There are several types of SPDs suitable for control panels.

1. Gas Discharge Tubes (GDTs) are suitable for high-energy surges but have slower response times.
2. Metal Oxide Varistors (MOVs) are fast-acting and can handle multiple surges.
3. Silicon Avalanche Diodes (SADs) have very fast response times, ideal for protecting sensitive electronics.
4. Hybrid SPDs combine multiple technologies for comprehensive protection.

Cascade protection involves using multiple levels of protection, starting with robust SPDs at the panel entry point and more sensitive devices closer to critical components. Proper earthing is crucial to effectively divert surge energy. Regular maintenance is necessary as SPDs can degrade over time.

UK Standards and Regulations

In the UK, several standards and regulations govern the use of surge protection devices:

1. BS EN 62305: This standard covers protection against lightning and includes guidance on surge protection.
2. BS 7671 (18th Edition IET Wiring Regulations): Section 443 deals with protection against transient over voltages of atmospheric origin or due to switching. Amendment 2 (2022) clarified this further where consequences of a surge would affect human life, etc.
3. BS EN 61643: This standard series covers low-voltage surge protective devices.
4. BS EN 60664-1: Addresses insulation coordination for equipment within low-voltage systems, including overvoltage categories.

These standards provide guidance on risk assessment, selection, and installation of SPDs. It's crucial to stay updated with these standards as they are periodically revised to reflect new technologies and practices.

When Might You Not Need Surge Protection?

While rare, there are situations where surge protection might not be necessary. These include areas with exceptionally stable power and no risk of lightning strikes, non-critical systems where occasional failures are acceptable, or panels containing only basic electromechanical components (though this is increasingly uncommon). However, given the relatively low cost of SPDs compared to the potential damage they prevent, it's generally advisable to err on the side of caution.

Conclusion

In the vast majority of cases, surge protection is not just recommended but essential for control panels in the UK. The potential costs of damage far outweigh the investment in proper protection. As with many aspects of electrical engineering, it's better to be proactive than reactive. Implement appropriate surge protection in your control panels, and you'll sleep better knowing your critical systems are safeguarded against electrical surges.

The information provided in this blog post is intended for general knowledge and guidance only. It does not constitute professional advice. Please consult a qualified professional for advice specific to your situation before making any decisions based on this information.