Siemens HNX3B120L - 1200 A, 3-Pole Circuit Breaker | AmpState

Siemens HNX3B120L is a 1200 A, 3-pole molded case circuit breaker designed for dependable branch circuit overcurrent and short-circuit protection in panelboards and load centers. From AmpState, this unit brings precise thermal-magnetic protection to residential, commercial, and light industrial settings where reliable power safety matters.

• Compact molded-case design maximizes panel space without compromising protection, helping you fit larger systems into standard enclosures.
• Thermal-magnetic trip unit delivers stable, repeatable protection by combining thermal overcurrent sensing with magnetic short-circuit sensing for fast, predictable trips when needed.
• OEM-compatible performance engineered to pair seamlessly with matching Siemens load centers and panelboards, simplifying replacement and panel upgrades.
• Rugged, long-life construction built to endure the demands of busy electrical environments, from installation to daily operation in demanding locations.

What problems does the HNX3B120L solve?

When protected by a high-capacity three-pole breaker, large feeders and three-phase circuits stay safeguarded against overloads and short circuits, reducing the risk of equipment damage and downtime. The thermal-magnetic design minimizes nuisance trips while ensuring swift response to dangerous faults, keeping panels and connected devices safer and more reliable.

Ideal use cases

• Residential and commercial panelboards that require robust protection for three-phase feeders
• Light industrial electrical rooms with substantial load demands
• HVAC, motor control centers, and large equipment feeds within safe, code-compliant panels

Technical snapshot

• Manufacturer: Siemens
• Part number: HNX3B120L
• Type: Thermal-magnetic molded case circuit breaker
• Amperage rating: 1200 A
• Number of poles: 3
• Application: Branch circuit overcurrent and short-circuit protection

Installation and compatibility tips

For optimal performance, pair the HNX3B120L with Siemens OEM load centers and panelboards designed to accommodate this 3-pole, 1200 A molded case breaker. Verify that the panel’s space, bus configuration, and labeling support a high-capacity, three-phase protection device. This breaker is designed for straightforward replacement in compatible Siemens panel systems, helping you streamline upgrades and maintenance.

Who benefits

Electrical contractors, facilities managers, and maintenance teams seeking a dependable, high-capacity protection solution for large panelboard installations will appreciate the Siemens HNX3B120L. It offers precise protection characteristics, easy integration with Siemens ecosystems, and a space-efficient form factor that supports scalable electrical design.