Siemens | JJ3S400 | Circuit Breaker | 400A | 3-Pole | 600V

Introducing Siemens JJ3S400, a rugged, high-current circuit breaker engineered for demanding 3-phase power distributions. With a 400A rating across 3 poles and operation up to 600V, this unit is designed for maintenance, retrofit, and replacement projects where exact specifications matter.

Key specifications

• Amperage: 400A
• Pole configuration: 3-Pole
• Voltage rating: 600V
• Part number reference: JJ3S400 (best compatibility reference)

Why choose the Siemens JJ3S400 for your panel

As a Siemens part, this breaker is built to align with Siemens distribution equipment and legacy 3-phase systems. It’s tailored for installations that require a precise match to existing protection schemes, ensuring seamless operation without the guesswork of mismatched replacements.

Ideal use cases

• Maintenance replacements in commercial and industrial panels where 400A, 3-Pole, 600V protection is specified
• Retrofit projects upgrading older gear to modern Siemens-compatible protection
• New installations that demand strict adherence to the JJ3S400 specification to maintain system coordination

How this part solves your problems

With the exact amperage, pole configuration, and voltage, it eliminates over- or under-protection risks. Rely on a proven Siemens design to minimize nuisance trips, protect expensive equipment, and keep power distribution running smoothly during service or upgrades.

Compatibility and ordering guidance

Before ordering, verify fit and ratings against your panel labeling and the equipment’s protection scheme. The JJ3S400 part number is your strongest reference for achieving a clean replacement or retrofit with minimal system disruption.

Installation and safety notes

Wiring and installation should be performed by a qualified electrical professional in accordance with all applicable safety standards. Ensure the main power is de-energized and follow manufacturer guidelines for torque, enclosure clearance, and proper bus bar engagement.

Maintenance and longevity tips

• Keep spare JJ3S400 units on hand for planned maintenance windows to reduce downtime
• Document the exact part number and panel location for future service cycles
• Inspect surroundings for signs of wear or overheating during routine maintenance checks