Understanding the Role of UPS in Protecting Against Power Surges

When it comes to protecting sensitive electronics from power surges, an Uninterruptible Power Supply (UPS) is often mentioned. But does a UPS effectively protect against power surges, and what are its limitations? This article delves into the details of UPS and power surge protection.

Does a UPS Protect from Power Surges?

Yes, an Uninterruptible Power Supply (UPS) can protect against power surges. Most UPS units include surge protection features that help safeguard connected devices from voltage spikes. However, the effectiveness of surge protection can vary based on the model of the UPS. It is important to check the specifications of the UPS to ensure it meets your protection needs.

The Dual Functionality of a UPS

A UPS provides battery backup during power outages, ensuring that your devices remain operational for a certain period. This dual function makes it a valuable tool for protecting sensitive electronics, such as computers and networking equipment.

Surge Protection vs. Battery Backup

It is important to understand that while a UPS can provide some level of surge protection, it is not designed as a stand-alone solution. Surge protection focuses on managing voltage spikes, but the battery backup function ensures continued operation during power outages. While the batteries do provide some surge protection for the load circuit, the level of protection is limited compared to standalone surge suppressors.

Understanding the Limitations of Surge Protection

Some manufacturers use Metal-Oxide Varistors (MOV) for voltage spike attenuation. However, for these devices to work properly, they must be in series with a fuse or breaker. MOV devices can fail open occasionally, offering no protection during such failures. When MOV devices fail in short circuit, they can trip the breaker or blow the new fuse, indicating a need for replacement.

Current Standards and Recommendations from a Senior Engineer

The current standards for surge protection are considered inadequate, and major improvements are warranted. Here are the recommendations from a senior professional engineer:

MOV Devices Need an Auxiliary Contact to Trip the Main Breaker

Install an auxiliary contact to trip the main breaker that is equipped with a shunt trip. This ensures proper functioning.

If Fuses Are the Interrupting Mechanism, Use Current-Limiting Fuses

Select these fuses by a professional knowledgeable in the subject. Ensure sufficient MOV devices are installed in parallel to make the main fuses trip and not isolate the MOV devices through a feeder breaker.

Expensive Solutions vs. Best Arrangement

Using breakers with shunt trips and fused mains with extra MOV devices is expensive. The best arrangement is to place a box upstream of the distribution panel with incoming current-limiting fuses. Connect this to a pair of contactors, one NO and the other NC. Energize the contactors to let electricity flow to the distribution panel. When not energized, the distribution panel input is connected to ground.

Regular Replacement and Testing

Replace the MOV devices every time they cause a trip before resetting the trip relay. Keep spares on hand and ensure the MOV device is modular with replaceable MOV pieces.

Use of Soft Iron Core Magnetic Core on Incoming Power Cable

Using a soft iron core on the incoming power cable is effective and cost-effective. Avoid using it on Ethernet, TV, or other high-frequency cables.

Conclusion

While a UPS is a valuable tool for protecting against power surges and power outages, it has limitations. Understanding these limitations and implementing additional measures as suggested by professionals can significantly enhance your protection against power surges.

Keywords: UPS, Power Surge, Surge Protection