Siemens ED42S125 A - 125 A, 480 V, 2-Pole Bolt-On Circuit Breaker | AmpState

Siemens ED42S125A is a 125A, 480V, 2-pole bolt-on molded case circuit breaker designed to deliver dependable branch circuit overcurrent and short-circuit protection in panelboards and loadcenters. Built for demanding electrical environments, it combines rugged mounting with precise protection to keep systems running smoothly.

Why bolt-on mounting matters

Secure bolt-on mounting provides a rigid, vibration-resistant bus connection that stays tight through start-ups and heavy loads. This stability helps maintain consistent electrical contact, reduces the risk of loose connections, and minimizes nuisance trips in environments with equipment vibration or frequent cycling.

Reliable protection with a thermal-magnetic trip

The ED42S125A features a thermal-magnetic trip unit for stable, repeatable protection performance. The thermal element handles overloads with predictable time-delay, while the magnetic element responds instantly to short circuits, helping to isolate faults quickly and protect wiring and devices downstream.

Designed for compatibility and versatility

Engineered to be compatible with matching OEM load centers and panelboards, this 2-pole breaker offers a seamless retrofit or new-install solution in systems that require robust 480V fault protection. Its molded-case design supports reliable operation across a range of ambient conditions and duty cycles.

Ideal applications

• Residential, commercial, and light industrial electrical installations requiring reliable 2-pole protection
• Panelboards and loadcenters where 480V systems are in operation
• Branch circuit protection for motors, lighting, and other electrical feeders in demanding environments

Key specifications at a glance

• Manufacturer: Siemens
• Part Number: ED42S125A
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 125A
• Voltage Rating: 480V
• Number of Poles: 2
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Practical tips and practical scenarios

• Use in panelboards and loadcenters that require a sturdy, bolt-on connection for high-vibration environments or installations with motor loads.
• Choose when you need a reliable 125A protection device for 480V feeders, ensuring coordinated protection with upstream disconnects and downstream devices.
• Pair with compatible Siemens OEM panels to simplify installation and maintain warranty coverage.

Why this Siemens breaker stands out

Unlike plug-in alternatives, the ED42S125A’s bolt-on design delivers a superior, vibration-resistant connection that remains durable over time. The combination of a thermal-magnetic trip and molded-case construction offers predictable protection behavior, helping you minimize downtime and protect wiring and equipment with confidence. For projects that demand robust 480V branch circuit protection in panelboards and loadcenters, the Siemens ED42S125A is a purpose-built choice that aligns with industrial and commercial electrical standards while remaining suitable for select residential applications.