Siemens FXD63B250 Circuit Breaker

Siemens FXD63B250 Circuit Breaker (Sentron FXD Series)

 

 

The Siemens FXD63B250 is a molded case circuit breaker (MCCB) from Siemens’ Sentron FXD series, designed for industrial and commercial power distribution protection.

It is used to protect electrical systems from overload, short circuit, and fault currents in medium-to-high power circuits.

Key Specifications

• Model: FXD63B250
• Brand: Siemens
• Series: Sentron FXD (FD Frame)
• Product Type: Molded Case Circuit Breaker (MCCB)
• Poles: 3P (three-phase)
• Rated Current: 250A
• Rated Voltage: Up to 600V AC
• Interrupting Capacity:
  • 35kA @ 480V
  • ~22kA @ 600V (variant dependent)
• Trip Unit:
  • Thermal-magnetic (LI: Long-time + Instantaneous)
• Mounting Type:
  • Bolt-on / panelboard mounting
• Standard:
  • UL 489 / IEC 60947-2 (typical for this series)

What it does (simple explanation)

This breaker protects heavy electrical loads by automatically disconnecting power when:

• Overload occurs (too much current over time)
• Short circuit happens (instant fault current)
• System fault / wiring issue occurs

Power Flow:
Utility / Transformer
↓
FXD63B250 Breaker
↓
Industrial load (motors, distribution panels, machinery)

Features & Advantages

• High interrupting capacity (industrial fault protection)
• Thermal-magnetic trip system:
  • Thermal → overload protection
  • Magnetic → instant short-circuit protection
• Suitable for 3-phase industrial distribution
• Bolt-on design for secure panel installation
• Compact FD frame construction
• Reliable Siemens Sentron engineering standard

Applications

• Industrial distribution panels
• Factory power systems
• Large motors and machinery feeders
• HVAC power distribution
• Commercial buildings
• Sub-distribution boards