Square D MJL36300 - 300 A, 600 V, 3-Pole Circuit Breaker | AmpState

Meet the Square D MJL36300 — a 300A, 600V, 3-pole molded case circuit breaker designed to deliver dependable branch circuit overcurrent and short-circuit protection in panelboards and load centers. Built for residential, commercial, and light industrial environments, this unit combines a compact form factor with robust performance to optimize space without compromising safety.

Compact, space-smart design

The MJL36300 features a streamlined molded case that fits neatly into dense panel layouts, helping you maximize enclosure capacity. Its compact footprint makes it an ideal upgrade or replacement part in existing installations where panel space is at a premium, yet reliable protection remains non-negotiable.

Thermal-magnetic protection for stable performance

Equipped with a thermal-magnetic trip unit, this breaker responds to both gradual overloads and sudden short-circuit events. The thermal element handles long-term current fluctuations, while the magnetic element provides rapid interruption during high-energy fault conditions. The result is repeatable, stable protection that minimizes nuisance trips and protects connected equipment.

Three-pole design for balanced, three-phase protection

With three poles, the MJL36300 is tailored for 3-phase systems, ensuring synchronized interruption across all conductors. This is essential for protecting motors, lighting, and other three-phase equipment, reducing the risk of damage from unbalanced faults and ensuring reliable performance in commercial and light industrial settings.

Compatibility and installation

Designed to be compatible with matching OEM loadcenters and panelboards, the MJL36300 simplifies replacement and upgrades. Installation is straightforward for professionals familiar with Square D products, and the 600V rating expands its suitability for a wide range of electrical distributions.

Ideal use cases

• Residential/retrofit panels where a high-current, reliable 3-pole breaker is needed
• Commercial distribution panels requiring robust short-circuit protection for three-phase loads
• Light industrial control panels and motor circuits that demand precise thermal-magnetic protection
• Panelboard and loadcenter upgrades where space efficiency and OEM compatibility matter

Technical snapshot

• Manufacturer: Square D
• Part Number: MJL36300
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 300 A
• Voltage Rating: 600 V
• Number of Poles: 3
• Application: Branch circuit overcurrent and short-circuit protection

When you need dependable protection that respects space constraints and delivers consistent performance across diverse environments, the Square D MJL36300 stands out as a thoughtful, capable choice for panelboards and load centers.