Square D EJB14040 - 40 A, 277 V, 1-Pole Bolt-On Circuit Breaker | AmpState

Meet the Square D EJB14040 from AmpState — a purpose-built 40 A, 277 V, 1-pole bolt-on molded case circuit breaker engineered to protect your branch circuits with precision. Designed for panelboards and load centers, this unit delivers dependable overcurrent and short-circuit protection where it matters most.

• Secure bolt-on mounting ensures a rigid, vibration-resistant connection to the panel bus, reducing movement and maintaining consistent electrical contact even in environments with machinery or heavy use.
• Thermal-magnetic trip unit combines thermal overload protection with instantaneous magnetic actuation for short circuits, providing stable, repeatable protection performance under varying load conditions.
• OEM-compatible design engineered to integrate with matching Square D load centers and panelboards for a seamless, reliable fit and straightforward replacement.
• Versatile application suitable for residential, commercial, and light industrial settings where 277 V circuits power lighting, equipment, and control devices.
• Precise 1-pole protection targeted at single-circuit branches, delivering dedicated protection without unnecessary disruption to adjacent circuits.
• Molded case construction provides rugged, durable performance in everyday electrical installations, with consistent performance across temperature and vibration conditions.

Technical details at a glance

• Part number: EJB14040
• Amperage rating: 40 A
• Voltage rating: 277 V
• Number of poles: 1
• Mounting style: Bolt-on
• Type: Thermal-magnetic molded case circuit breaker
• Application: Branch circuit overcurrent and short-circuit protection

Why this breaker adds value in real-world installations

In commercial and light industrial panels, reliability and plug-and-play compatibility matter as much as protection. The Square D EJB14040 is built to stand up to the daily rigors of 277-volt circuits—think office lighting, HVAC controls, and auxiliary equipment—while providing a robust bus connection that resists loosening from vibration or thermal cycling. By pairing a stable thermal-magnetic trip with a secure bolt-on mount, you gain predictable protection that won’t drift as loads shift throughout the day.

If you’re upgrading an existing panelboard or stocking a replacement inventory, this 40 A, 277 V breaker from Square D offers a direct, compatible option for 1-pole circuits. Its design emphasizes longevity and consistency, helping reduce nuisance trips and ensuring that critical circuits stay energized when they should.

Who benefits most

• Electrical contractors assembling or upgrading commercial panelboards and load centers that operate on 277 V systems.
• Facilities managers overseeing lighting and power distribution in office buildings, retail spaces, healthcare clinics, or light industrial facilities.
• Service technicians replacing aging breakers in single-pole branch circuits where a bolt-on, molded case design is preferred for durability.

Practical tips for optimal use

• Confirm panel compatibility: ensure the host panelboard is rated for 277 V operation and accepts bolt-on molded case breakers of the EJB family.
• Plan for serviceability: bolt-on mounting facilitates quick removal and replacement in crowded or hard-to-reach panel areas.
• Match trip characteristics to load: use the thermal-magnetic protection to cover both sustained overloads and short-circuit events for consistent performance.
• Keep spares on hand: for mission-critical commercial circuits, maintain a ready-to-install replacement to minimize downtime during maintenance windows.
• Follow manufacturer guidelines: install only in panels designed to accommodate this specific ampacity and voltage rating to preserve panel integrity and safety.

With the Square D EJB14040 40 A, 277 V, 1-Pole Bolt-On Circuit Breaker, AmpState delivers a rugged, dependable solution that prioritizes precise protection, straightforward installation, and compatibility with standard Square D panel systems. It’s the practical choice when you need solid branch-circuit protection that stands up to the demands of commercial and light industrial electrical environments.