Square D NJG3B300 - 300 A, 600 V, 3-Pole Bolt-On Circuit Breaker | AmpState

The Square D NJG3B300 is a 300 A, 600 V, 3-pole bolt-on molded case circuit breaker engineered for dependable branch circuit overcurrent and short-circuit protection in panelboards and load centers. With a secure bolt-on mounting, it delivers a rigid, vibration-resistant connection to the bus, helping maintain consistent performance even in challenging installations.

• Bolt-on mounting for reliability: A secure, vibration-resistant connection reduces the risk of bus movement and contact wear, enhancing long-term protection integrity.
• Thermal-magnetic trip unit: Combines thermal overload protection with instantaneous magnetic trip for fast, stable response to faults, minimizing nuisance trips and safeguarding downstream equipment.
• Three-pole, 600 V design: Perfect for three-phase systems up to 600 V, making it suitable for commercial and light industrial electrical distributions.
• OEM panel compatibility: Specifically designed to integrate with matching Square D OEM load centers and panelboards for seamless, code-compliant protection.
• Versatile application: Although built for demanding environments, it’s suitable for residential, commercial, and light industrial installations requiring robust branch-circuit protection.

Why this breaker stands out

Unlike generic substitutes, the NJG3B300 is built to align with Square D panel ecosystems, ensuring consistent trip characteristics, mechanical fit, and reliable performance across installations. The combination of a secure bolt-on mount and a thermal-magnetic trip unit translates into predictable protection curves, reducing downtime and simplifying panel maintenance.

Key specifications at a glance

• Manufacturer: Square D
• Part number: NJG3B300
• Type: Thermal-magnetic molded case circuit breaker
• Amperage rating: 300 A
• Voltage rating: 600 V
• Poles: 3
• Mounting style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Ideal use scenarios

Install the NJG3B300 in commercial distribution panels to safeguard multi-branch circuits, or in light industrial panelboards where reliable three-phase protection is essential. It’s also a practical upgrade for existing Square D systems requiring a robust bolt-on solution with predictable trip performance. For new builds, pair this breaker with compatible load centers to ensure a cohesive protection strategy from main service to feeder branches.