Square D EJB34090 - 90 A, 480 V, 3-Pole Bolt-On Circuit Breaker | AmpState

Meet the Square D EJB34090—a 90A, 480V, 3-Pole Bolt-On Molded Case Circuit Breaker designed for dependable branch circuit protection in panelboards and load centers. Built to endure the demands of commercial and light industrial environments, this breaker combines robust hardware with intelligent protection to keep systems running smoothly.

• Secure bolt-on mounting: A rigid, vibration-resistant bus connection that stays put in demanding installations, reducing the risk of loose connections and arcing over time.
• Thermal-magnetic trip unit: Integrates thermal overload protection with magnetic short-circuit protection for stable, repeatable performance. It trips reliably on genuine faults while resisting nuisance trips from normal load fluctuations.
• OEM-compatible design: Specifically engineered to fit Square D panelboards and load centers, ensuring seamless integration with existing electrical infrastructure.
• Three-pole, 480V protection: Ideal for three-phase distribution systems common in commercial spaces and light industrial settings, safeguarding feeders and large branch circuits at a high voltage rating.
• Versatile for multiple environments: Suitable for residential-adjacent commercial spaces, small campuses, and light industrial applications where dependable overcurrent and short-circuit protection matters.

What problems does it solve?

When a fault occurs, the EJB34090 responds quickly to interrupt excessive current, preventing damage to wiring, equipment, and downstream devices. Its bolt-on design minimizes bus connection movement under vibration, reducing potential wear and electrical noise. With a thermal-magnetic trip unit, you get protection that mirrors real-world fault conditions—sensitive to short circuits while preventing unnecessary trips during normal startup surges.

Ideal use cases

• Feeder circuits in commercial panelboards for offices, retail spaces, and small data rooms.
• Three-phase distribution sections in light industrial facilities requiring 90A protection at up to 480V.
• Upgrades or replacements in Square D installations where OEM compatibility and secure mounting are priorities.

Technical snapshot

• Manufacturer: Square D
• Part number: EJB34090
• Type: Thermal-magnetic molded case circuit breaker
• Amperage rating: 90A
• Voltage rating: 480V
• Number of poles: 3
• Mounting style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Available through AmpState, the Square D EJB34090 is a purpose-built solution for reliable three-phase protection where space, performance, and compatibility with Square D panels matter most. Whether you're wiring a new commercial installation or upgrading an existing panel, this bolt-on breaker delivers clear, actionable protection that technicians can trust.