How to Choose the Right ATS for Your Power System: CB-Class vs PC-Class Explained

When designing a backup power system, choosing the right Automatic Transfer Switch (ATS) is critical for safety and reliability. But with different types available — CB-class and PC-class — making the right choice can be confusing. Here's what you need to know.

What is an ATS? An Automatic Transfer Switch monitors your primary power source and automatically switches to backup power when an outage is detected. It ensures continuous power supply for critical loads.

CB-Class ATS (Circuit Breaker Type) CB-class ATS uses circuit breakers as the switching elements, combined with motorized operation and dual interlock protection. Key advantages: - Built-in overload and short-circuit protection - Higher short-circuit withstand capacity (typically 10kA+) - Both mechanical and electrical interlocking for maximum safety - Break-before-make switching logic prevents backfeeding - Suitable for critical and high-power applications

Best for: Data centers, industrial facilities, hospitals, and any application where safety and protection are priorities.

PC-Class ATS (Load Switch Type) PC-class ATS uses load break switches for switching. Key characteristics: - Lower cost - No built-in overload protection - Lower short-circuit withstand capacity (typically 6-8kA) - Manual operation only in basic models

Best for: Small commercial applications, non-critical loads, and budget-conscious projects with lower safety requirements.

Why SPM Recommends CB-Class At SPM, we standardize on CB-class motorized ATS for all our power solutions because: - Safety first — Dual interlock and break-before-make logic eliminates the risk of backfeeding to the grid - Protection built-in — Circuit breakers protect both the generator and your loads - Compliance ready — Meets IEC 60947-6-1 standards and international project requirements - Long-term reliability — Higher durability for frequent switching operations

Making the Right Choice When selecting an ATS, consider: - Your application's criticality - Required short-circuit withstand rating - Local electrical codes and standards - Total cost of ownership, not just upfront price

Not sure which ATS is right for your project? Our technical team can help you select the right solution based on your specific requirements. Contact us for a free consultation.