Siemens | HEG3B125 | Circuit Breaker | 125A | 3-Pole | 600V

The Siemens HEG3B125 circuit breaker is a purpose-built protection device for 3‑phase electrical systems, engineered to guard circuits up to 125 amperes at voltages as high as 600V. Ideal for maintenance, retrofit, and replacement projects, this 3‑pole unit delivers reliable overcurrent protection with a proven Siemens build quality that technicians trust in demanding environments.

• Amperage: 125 A
• Poles: 3‑Pole (three‑pole)
• Voltage rating: 600 V
• Part number: HEG3B125
• Application fit: Compatible with panels designed to accept this Siemens model for maintenance, retrofit, and replacement projects

Designed for compatibility and easy substitution

When you need a like‑for‑like replacement, the HEG3B125 is designed to slot into compatible Siemens panels and other assemblies that specify this exact model. The part number is the most reliable reference for compatibility, so confirm the fit and ratings before ordering to minimize downtime and ensure continued protection of your 3‑phase system.

Why choose this Siemens 125A, 3‑pole breaker

• Trustworthy protection for 3‑phase systems: A dedicated 3‑pole design protects all three legs in a three‑phase circuit up to 125A, helping prevent equipment damage and electrical hazards.
• Clear compatibility signal: The HEG3B125 is the explicit part reference to match with compatible panels, reducing guesswork during replacement or retrofit.
• Reliable, long‑cycle maintenance option: As a Siemens part, it aligns with existing protection schemes and panel architectures, promoting consistent performance over time.

Ideal use cases

• Maintenance or service outages on three‑phase, 600V environments where 125A protection is required
• Retrofit projects updating older gear to a Siemens‑standard protection device
• Replacement for failed breakers in compatible Siemens or Siemens‑style panels

Compatibility and ordering tips

To ensure a trouble‑free substitution, use the exact part number HEG3B125 as the primary reference. Always verify fit and ratings against the target panel’s specification before purchase. If you’re uncertain, consult your panel documentation or a qualified electrician to confirm that the circuit breaker matches the panel’s intended protection and connector configurations.

Safety and installation notes

Work with the main power secured and follow applicable electrical codes and manufacturer guidelines. Use appropriate PPE and ensure the replacement procedure is performed by trained personnel familiar with three‑phase protection devices and Siemens hardware.