Siemens NMG3B800L - 800 A, 3-Pole Circuit Breaker | AmpState

The Siemens NMG3B800L is a rugged 800 A, 3-pole molded case circuit breaker designed to deliver dependable branch circuit overcurrent and short-circuit protection in panelboards and load centers. With a compact molded case and a thermal-magnetic trip unit, this breaker combines space efficiency with precise, repeatable protection for demanding electrical systems.

Why the NMG3B800L stands out

• High-current efficiency: An 800 A rating makes it ideal for protecting large feeders and high-demand circuits in residential, commercial, and light industrial environments.
• Compact molded-case design: Contributes to tighter, cleaner panel layouts by preserving valuable panel space without sacrificing protection.
• Thermal-magnetic trip unit: Delivers stable, predictable tripping behavior across a range of fault conditions, reducing nuisance trips and ensuring reliable coordination with other protective devices.
• Panel and loadcenter compatibility: Engineered to work seamlessly with matching OEM Siemens loadcenters and panelboards, helping to maintain consistent trip curves and electrical coordination.

Ideal use cases

• Main feeder protection in large residential or commercial panelboards where space-efficient breakers are essential.
• Branch-circuit protection for high-current circuits powering equipment, motors, or critical loads in light industrial settings.
• Retrofits and panel upgrades that require a dependable, Siemens‑matched protection solution to maintain system coordination and code compliance.

Technical snapshot

• Manufacturer: Siemens
• Part Number: NMG3B800L
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 800 A
• Poles: 3
• Application: Branch circuit overcurrent and short-circuit protection

Practical guidance for optimal performance

To maximize protection and longevity, pair the NMG3B800L with compatible Siemens panelboards and loadcenters, ensuring coordinated trip settings across protective devices. Verify enclosure ratings, torque specifications for connection terminals, and proper clearances around the breaker for heat dissipation. When planning upgrades or replacements, consider the 800 A rating as a way to consolidate protection for multiple high-demand circuits under a single, reliable device.

Designed for professionals who demand reliability and exacting performance in large-panel applications, the Siemens NMG3B800L delivers precise protection where it matters most—keeping your electrical system safe, compliant, and ready to perform.