Peak Surge Capacity: Surge Protection Device Selection and Longevity

Imagine a colossal wave of electricity crashing through your facility’s electrical system. Will your surge protection device endure devastating force, or will it crumble under pressure? The answer lies in a critical specification: peak surge capacity.

In this episode of The Power Grid, we’ll unravel the significance of peak surge capacity in the world of power protection. We’ll explore how this metric influences the selection and lifespan of your Surge Protection Device (SPD), and we’ll share valuable insights to help you make informed decisions when safeguarding your critical equipment.

What is Peak Surge Capacity?

Peak surge capacity is the ultimate test of surge protection. It signifies the maximum surge current, measured in kiloamperes (kA), that the device can safely handle before sustaining damage. Think of it as the SPD’s “breaking point” – the threshold beyond which its protective capabilities are compromised.

The higher the peak surge capacity, the more robust the SPD and the better equipped it is to handle large and frequent power surges.  It’s a crucial factor to consider when selecting the right power protection device for your facility, as it directly impacts the level of protection your equipment receives.

Factors Influencing Peak Surge Capacity Selection

Choosing the appropriate peak surge capacity for your SPD isn’t a one-size-fits-all scenario. Several factors come into play, each influencing the level of protection required.

• Exposure Level: The first and foremost consideration is the level of exposure your facility faces. Is it in a high-risk area prone to lightning strikes or other electrical disturbances? The higher the exposure, the higher the peak surge capacity you’ll need.
• IEEE Surge Categories: The Institute of Electrical and Electronics Engineers (IEEE) has categorized surge environments into three levels: C (high exposure), B (medium exposure), and A (low exposure). The category your facility falls under will guide you toward the appropriate peak surge capacity range.
• External Surges: Beyond the general exposure level, consider the specific types of external surges your facility may encounter. Areas with frequent lightning strikes will require SPDs with higher peak surge capacities to withstand these powerful events.
• Equipment Value and Downtime Cost: The value of the equipment you’re protecting and the potential cost of downtime due to a surge are crucial considerations. High-value equipment and processes that are sensitive to downtime may warrant a higher level of protection, necessitating an SPD with a greater peak surge capacity.

Expertise in Surge Protection Device Selection

At Power Protection Products (P3), we understand the complexities of surge protection and the importance of selecting the right device for your unique needs.  Our team of experts can assess your facility’s surge risk and recommend the most suitable SPDs to ensure optimal protection and longevity.

The Relationship Between Peak Surge Capacity and SPD Lifespan

While peak surge capacity indicates an SPD’s ability to handle a single, powerful surge, it also plays a crucial role in determining the device’s overall lifespan.  Power surges, even those below the peak surge capacity, gradually wear down the components of an SPD, reducing its effectiveness over time.

Higher Capacity, Longer Life:

SPDs with higher peak surge capacities are built with more robust components and are designed to withstand a greater number of surge events. This translates to a longer lifespan and greater value for your investment.

Our Real-World Example

In the late 1990s, Power Protection Products received an order for eight 80 kVA surge suppression units for a manufacturing facility in Texas.  Unfortunately, the units were undersized for the high-exposure environment, and all eight units failed prematurely due to repeated surge events. 

This costly lesson underscores the importance of selecting SPDs with adequate peak surge capacity.

Lifetime Ratings:

Surge protection devices are typically rated for their expected lifetime in kA. This rating indicates how much total surge current the SPD can handle throughout its life before its components degrade to the point where they need to be replaced.  

Selecting an SPD with a lifetime rating that matches or exceeds the expected surge exposure in your geographic location is essential for ensuring long-term protection.

Surge Protection Device Configuration: Modes of Protection

Surge protection devices (SPDs) offer comprehensive protection by utilizing multiple modes of protection within a single unit. For instance, in a three-phase Y system, there are modes of protection

• Line-to-Ground: This mode safeguards each of the three-phase conductors (A, B, and C) against surges that travel from the power lines to the ground.
• Line-to-Neutral: This mode protects each phase conductor against surges that travel to the neutral conductor.
• Neutral-to-Ground: This final mode protects the neutral conductor itself against surges to the ground.

While some SPDs may also include line-to-line protection, these modes are generally considered less critical. The line-to-neutral and line-to-ground protection modes are often the primary focus, as they address the most common surge pathways.

Selecting the Right Peak Surge Capacity: A Multi-Faceted Approach

Choosing the right peak surge capacity for your power protection device is a decision that requires careful consideration of various factors. It’s not as simple as opting for the highest possible rating. Instead, it involves understanding your specific environment and needs.

Geographic Location

The frequency and intensity of lightning strikes and other electrical disturbances vary significantly across different regions. Areas prone to frequent lightning storms, for example, will generally require SPDs with higher peak surge capacities to withstand the increased surge risk.

Facility Type and Exposure Level

The type of facility you’re protecting (industrial, commercial, residential) and its specific location within the electrical system (rooftop, service entrance, branch panel) play a significant role in determining the expected surge exposure. A facility with a high exposure level, such as a rooftop location, will need an SPD with a higher peak surge capacity compared to a facility with a low exposure level, such as a branch panel located deep within the electrical system.

Downstream Protection

If your facility employs a layered surge protection approach with multiple SPDs installed at different points in the electrical system, the peak surge capacity requirements can vary. 

The main service entrance SPD typically needs the highest peak surge capacity to handle the most powerful surges. Downstream SPDs, closer to the protected equipment, can have lower peak surge capacities as they are exposed to attenuated surges.

Remember, a higher peak surge capacity doesn’t automatically translate to better protection in terms of let-through voltage, which is the voltage that passes through the SPD during a surge. However, a higher peak surge capacity generally indicates a longer lifespan for the SPD, as it can withstand more surge events before its components degrade.

Partnering with Power Protection Products for Expert Guidance

Our team of power quality experts can assess your facility’s specific needs, evaluate your surge risk profile, and recommend the ideal surge protection device to provide optimal protection and longevity.

Don’t leave the safety and reliability of your electrical system to chance. Contact Power Protection Products today to learn more about our surge protection solutions and ensure your facility is equipped to withstand even the most challenging power surges.

 Choosing the right peak surge capacity is an investment in the long-term health and resilience of your electrical infrastructure.