Siemens 5SY4120-7 20A 1-Pole 400 V Circuit Breaker

The Siemens 5SY4120-7 20A 1-Pole 400 V Circuit Breaker is a purpose-built protection device designed for reliable single-circuit safety in 400 V electrical systems. As a genuine Siemens part, it combines precise protective timing with dependable construction, making it a trusted choice for installers and maintenance teams who value consistency and long-term performance.

• Model / Part: 5SY4120-7
• Current rating: 20 A
• Poles: 1
• Voltage rating: 400 V

What it does

• Provides reliable overcurrent protection for a single branch circuit within 400 V electrical installations, helping prevent wiring damage and equipment failure.
• Offers a compact, easy-to-install form factor compatible with Siemens panels and standard electrical enclosures, reducing setup time in retrofit or new-build projects.
• Clear model identification (5SY4120-7) supports straightforward maintenance, audits, and future replacements without guesswork.
• Engineered by Siemens to deliver consistent, repeatable trip characteristics, giving you predictable protection when it matters most.

Ideal applications

• Commercial and light industrial panels where a single 20 A circuit requires solid protection in a 400 V system.
• Replacement or upgrade scenarios in Siemens-based electrical installations that demand exact compatibility with the 5SY4120-7 specification.
• Dedicated circuits such as lighting, receptacles, or drives within 400 V networks that benefit from reliable, straightforward protection.

Installation and usage tips

• Verify compatibility with your panel and ensure the system voltage does not exceed 400 V.
• Install with power turned off and follow standard electrical codes for safe wiring, termination, and mounting.
• Retain the exact part number (5SY4120-7) during replacements to maintain circuit protection consistency and panel interoperability.

Choosing the Siemens 5SY4120-7 means opting for a dedicated, genuine component that aligns with Siemens’ quality standards and your need for dependable 20 A, 1-Pole protection in 400 V environments. It’s a precise, practical upgrade or replacement that keeps critical circuits safeguarded while fitting neatly into existing Siemens-based installations.