Siemens ED21B045L - 45 A, 120 V, 1-Pole Bolt-On Circuit Breaker | AmpState

Siemens ED21B045L is a 45A, 120V, 1-pole bolt-on molded case circuit breaker designed to guard your electrical system with dependable branch circuit overcurrent and short-circuit protection. Built for panelboards and load centers, this device delivers steadfast performance in a compact, easy-to-integrate package.

Key advantages

• Secure bolt-on mounting provides a rigid, vibration-resistant bus connection that stays in place through everyday operation, minimizing the risk of loose contacts and intermittent trips.
• Thermal-magnetic trip unit combines precise thermal overload protection with fast magnetic short-circuit response, delivering stable, repeatable protection under varying loads and fault conditions.
• OEM-compatible design is engineered to work seamlessly with Siemens matching load centers and panelboards, simplifying replacement and maintenance in existing electrical systems.
• Versatile applications suited for residential, commercial, and light industrial environments, offering reliable protection across a wide range of service needs.

Specifications at a glance

• Manufacturer: Siemens
• Part Number: ED21B045L
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 45A
• Voltage Rating: 120V
• Number of Poles: 1
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Ideal use cases

• Residential panelboards where a reliable 45A, 120V protection device is needed for branch circuits serving living spaces, HVAC, or appliances.
• Commercial distribution panels that require durable bolt-on breakers capable of withstanding longer service runs and moderate vibration.
• Light industrial electrical feeds where consistent protection against overcurrent and short circuits is critical.
• Replacement in OEM Siemens load centers to maintain system compatibility and performance.

Installation and reliability

The ED21B045L’s bolt-on mounting delivers a solid, vibration-resistant connection to the bus, which helps maintain electrical integrity in busy panels and crowded electrical rooms. The integrated thermal-magnetic trip unit provides two-layer protection: thermal sensing for gradual overloads and magnetic trip for abrupt faults, reducing nuisance trips while ensuring fast isolation when faults occur. This combination is especially valuable in spaces where reliability and predictable performance are essential.

Why choose this Siemens breaker

• Design alignment with Siemens panels minimizes confusion during installation and ensures optimal compatibility with existing equipment.
• Targeted protection without compromise is achieved through a balanced approach to overload and short-circuit scenarios, protecting wiring insulation, devices, and overall system uptime.
• Clear path for upgrades and maintenance—a single 1-pole 45A unit can slot into compatible panelboards, helping you streamline replacements and reduce downtime.

For dependable, site-ready overcurrent protection in single-pole configurations, the Siemens ED21B045L delivers a precise, durable solution that professionals trust for residential, commercial, and light industrial electrical systems.