Square D | 999370 | Circuit Breaker | 70A | 3-Pole | 600V | 10kA | Bolt-On

Meet the Square D 999370 Circuit Breaker — a 70 Amp, 3-Pole, bolt-on protection device engineered for demanding 600V electrical systems and a 10kA interrupting capacity. This model is designed for maintenance, retrofit, and replacement tasks where exact specs matter, making it a dependable choice in commercial and industrial panels.

Key attributes include a robust bolt-on mounting for a solid, vibration-resistant connection, three-phase protection, and a 70A rating that aligns with common branch-circuit and feeder protection needs in 3-phase installations.

Why choose this Square D breaker? It’s built to endure frequent switching in demanding environments while delivering precise tripping performance when faults occur. The 600V rating enables safe operation across higher voltage panels, and the 10kA interrupting capacity provides a generous safety margin for fault currents. The part number 999370 is your most reliable reference for compatibility.

Key specifications

• Amperage: 70 A
• Poles: 3-Pole
• Voltage: 600 V
• Interrupting capacity: 10 kA
• Mounting: Bolt-On
• Part number: 999370
• Brand: Square D

Use case and ideal applications

This breaker is ideal for retrofit projects in existing Square D panels that require a 3-pole, 70A device, as well as maintenance or replacement in facilities with high electrical demand—think commercial buildings, manufacturing floors, and data centers where reliable 3-phase protection is essential.

What sets it apart

• Bolt-On mounting provides a secure, field-replaceable solution for compatible panels.
• 3-Pole configuration protects all three phases, simplifying wiring and panel organization.
• 600V rating expands the range of compatible equipment, while the 10kA interruption capacity offers strong protection against short-circuit events.
• Part number accuracy: 999370 ensures you’re selecting the exact device needed for proper fit and ratings.

Practical tips for installation and compatibility

• Always verify fit and ratings before ordering. The part number 999370 is the best reference for compatibility.
• Ensure your panel supports bolt-on breakers and that there is space for a 3-pole device.
• Match the amperage and voltage to the protected circuit and confirm the panel’s bus configuration to prevent misfit.
• Follow manufacturer torque specifications and safety guidelines during installation.