Siemens HJG3B300L - 300 A, 3-Pole Circuit Breaker | AmpState

The Siemens HJG3B300L is a 300A, 3-pole molded case circuit breaker crafted to deliver dependable branch circuit overcurrent and short-circuit protection in panelboards and loadcenters. Its compact molded-case footprint frees up valuable panel space while preserving rugged performance, making it an intelligent choice for demanding electrical installations.

Why the HJG3B300L stands out

• Compact molded case design maximizes interior space in panelboards and loadcenters, helping you fit more circuits without sacrificing protection or accessibility.
• Thermal-magnetic trip unit provides stable, repeatable protection by coordinating thermal overload sensing with instantaneous magnetic trip for short circuits. This means fewer nuisance trips and more predictable behavior under varying temperatures and loads.
• 3-pole configuration is ideal for three-phase systems, simplifying wiring, improving coordination, and reducing panel clutter in commercial and light industrial applications.
• OEM-compatible engineering is designed to pair with matching Siemens OEM loadcenters and panelboards, ensuring proper fit, mechanical alignment, and reliable trip coordination.
• Versatile application range suitable for residential, commercial, and light industrial environments, providing a single, dependable protection solution across multiple settings.

What problems does it solve?

Protecting branch circuits and sensitive equipment starts with a breaker you can trust. The HJG3B300L delivers precise protection where it matters most—catching overloads before they damage conductors and equipment, and clearing short circuits quickly to minimize damage and downtime. Its compact form factor reduces panel crowding, while the thermal-magnetic trip unit keeps protection consistent across hot attics, cool basements, or busy data/office environments. For installers, the harmonious compatibility with Siemens loadcenters means fewer compatibility surprises and smoother panel upgrades or retrofits.

Ideal use scenarios

• Main or feeder protection in residential service panels that require reliable 300A, 3-pole protection.
• Commercial electrical panels and small to mid-size industrial control panels needing robust branch circuit protection.
• Retrofits or replacements in existing Siemens systems where OEM compatibility supports seamless installation and coordinated trip curves.

Technical snapshot

• Manufacturer: Siemens
• Part Number: HJG3B300L
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 300A
• Poles: 3
• Application: Branch circuit overcurrent and short-circuit protection

Installation and maintenance tips

• Confirm panelboard compatibility with Siemens OEM devices to ensure correct fit and coordinated protection.
• Plan for three-phase circuits when sizing and wiring downstream equipment to take full advantage of the 3-pole configuration.
• Schedule routine inspections to verify the trip unit remains within specification and that connections remain tight to prevent overheating.