Siemens E21B040 40A 1-Pole 120 V Circuit Breaker

Meet the Siemens E21B040 40A 1-Pole 120V Circuit Breaker — a dependable, single-pole protective device designed to guard a dedicated 120-volt circuit in your residential panel. This Siemens circuit breaker (part number E21B040) delivers reliable overcurrent protection, helping prevent wiring damage and electrical hazards by interrupting fault currents when needed.

Key specs at a glance

• Current rating: 40 A
• Poles: 1
• Voltage rating: 120 V
• Part number: E21B040
• Brand: Siemens

Why this 40A, 1-Pole 120V breaker could be the right choice

This breaker is tailored for residential electrical panels that accommodate Siemens breakers. It provides targeted protection for a high-draw 120V circuit, allowing you to run equipment or outlets that demand more current without compromising the overall panel safety. The 40-amp rating means it’s designed for heavier loads than standard 15A or 20A circuits, while still delivering reliable interruption to protect conductors and connected devices.

What makes it stand out

• Precise current protection: A 40 A rating ensures controlled response to overloads on heavy-duty 120V branches, helping prevent overheating and electrical fires.
• Seamless Siemens integration: Built to fit Siemens panels and enclosures that support E-series breakers, making upgrades or replacements straightforward.
• Single-pole convenience: Ideal for dedicated 120V circuits where a single-pole protection is appropriate.
• Clear part identification: Part number E21B040 for accurate ordering and verification within your electrical system.

Ideal use cases

Consider this Siemens breaker when you need to protect a dedicated 120V circuit with higher current capacity. It’s well-suited for:

• Home workshops powering high-draw tools or air compressors on a single 120V branch
• Dedicated circuits for garage or utility room outlets housing larger appliances
• Upgrading an existing Siemens panel where a 40A, 1-pole protection is appropriate

Note: Always ensure compliance with local electrical codes and have a qualified professional handle installation. Verify that your panel accepts E21B040 breakers before replacement or installation.