Siemens HHFXD63B175 Molded Case Circuit Breaker | 175A 3-Pole 600V Bolt-On

Siemens HHFXD63B175 — 175 Amp Molded Case Circuit Breaker

The Siemens HHFXD63B175 is a heavy-duty, 3-pole thermal magnetic molded case circuit breaker engineered for demanding commercial and industrial power distribution applications. Part of Siemens' trusted Sentron Series FD Frame lineup, this breaker delivers ultra-high interrupting capacity and reliable overcurrent protection in a bolt-on form factor.

Key Specifications

• Part Number: HHFXD63B175
• Manufacturer: Siemens (Sentron Series)
• Frame Type: FD Frame (HHFXD)
• Current Rating: 175 Amperes at 40°C
• Voltage Rating: 600 VAC (50/60 Hz) | 500 VDC
• Number of Poles: 3-Pole / 3-Phase
• Interrupting Rating: 100 kAIC at 480V
• Trip Type: Thermal Magnetic — LI (Long-Time & Instantaneous)
• Connection Type: Bolt-On
• Trip Unit: Non-Interchangeable
• Standards: UL 489 Listed
• Dimensions: 9.50 in (L) × 4.50 in (W) × 4.0 in (D)
• Condition: New
• SKU: HHFXD63B175-N

Why Choose the HHFXD63B175?

The HHFXD prefix designates Siemens' highest interrupting capacity within the FD Frame series — making the HHFXD63B175 the go-to choice when fault current levels demand maximum protection. With a 100 kAIC interrupting rating at 480V, this breaker handles extreme short-circuit conditions found in large commercial buildings, data centers, manufacturing facilities, and industrial switchgear assemblies.

The thermal magnetic trip mechanism provides a dual-layer of protection: the thermal element responds to sustained overloads, while the magnetic element provides instantaneous trip response to high-magnitude fault currents — preventing equipment damage and reducing arc flash risk.

Ideal Applications

• Commercial and industrial panelboards
• Siemens P2, P3, S4, and S5 panelboard systems
• Motor control centers (MCCs)
• Distribution switchgear and switchboards
• Data centers and critical power infrastructure
• High-fault-current environments requiring 100 kAIC protection

What's Included

• Siemens HHFXD63B175 circuit breaker (new condition)
• Non-interchangeable thermal magnetic trip unit
• Load side lug terminals

Frequently Asked Questions

What does HHFXD mean in the Siemens part number?
In Siemens' FD Frame naming convention, "HH" indicates the highest interrupting capacity tier. "FXD" refers to the frame type with bolt-on mounting. Together, HHFXD signifies maximum fault-clearing capability — in this case, 100 kAIC at 480V.

What is the difference between HHFXD63B175 and HFXD63B175?
The HFXD63B175 is rated for 65 kAIC at 480V. The HHFXD63B175 provides a higher 100 kAIC interrupting rating, making it the correct choice for installations where fault current analysis indicates levels exceeding 65 kA.

Is the HHFXD63B175 UL Listed?
Yes. This breaker is UL 489 Listed and conforms to applicable ANSI/NEMA standards for molded case circuit breakers.

What connection type does this breaker use?
The HHFXD63B175 uses a bolt-on connection, ensuring a secure, low-resistance mechanical and electrical connection within the panelboard or switchgear assembly.

What panelboards is it compatible with?
This breaker is compatible with Siemens P2, P3, S4, and S5 panelboard series that accept FD Frame bolt-on breakers.