Siemens 3VA5120-6EC31-0AA0 0A 3-Pole 3 V Circuit Breaker Potential Transformer

Meet the Siemens 3VA5120-6EC31-0AA0, a purpose-built 3-pole protection and measurement device that blends circuit-breaking capability with a built-in potential transformer. Designed for three-phase systems, this compact unit delivers essential voltage sensing directly from the breaker, enabling seamless relay inputs and accurate metering without the need for separate transformers.

Why this 3-pole unit stands out

• Three-pole configuration: Optimized for balanced protection across all three phases in industrial power distribution.
• Integrated potential transformer: Provides the necessary voltage sensing for protective relays and metering, reducing wiring complexity and panel clutter.
• Low-voltage sensing output: 3 V secondary support aligns with common protection schemes and relay inputs.
• Part identification: Clear part number 3VA5120-6EC31-0AA0 ensures easy sourcing and compatibility within Siemens systems.
• Spec alignment: Current rating listed as 0 A with a 3 V sensing capability, suitable for integrated protection applications rather than sole current carrying.

Ideal use cases

Perfect for installation in 3-phase power panels, distribution boards, and motor control centers where space is at a premium and reliable voltage sensing is required. It’s particularly well-suited for protection schemes that rely on a compact, single-unit solution to provide both breaker action and voltage feedback to protective relays and metering equipment.

Key benefits in practice

• Wiring efficiency: Eliminates the need for separate potential transformers, simplifying the routing and connection of protection relays.
• Installer-friendly: Streamlines panel assembly by combining protection and sensing in one module.
• Traceability and serviceability: The Siemens part number supports straightforward replacement and compatibility checks within legacy and modern protection architectures.

Technical snapshot

Part number: 3VA5120-6EC31-0AA0
Poles: 3
Voltage rating (secondary): 3 V
Current rating: 0 A

Practical tips for deployment

When integrating this unit, verify that the 3 V potential transformer output is compatible with your relay inputs and metering devices. Use it in applications where a compact, dual-function protection and sensing solution reduces wiring complexity while maintaining reliable three-phase protection. Always follow your institution’s safety standards and Siemens installation guidelines to ensure proper mounting, connection, and maintenance.