ZINSCO QFB24 GTE SYLVANIA 3POLE 125A 240V CIRCUIT BREAKER

Description:

The Zinsco QFB24 (commonly referenced as QFB24-125-3 or QFB243125) is a 125 Amp, 3-pole molded case circuit breaker designed for use in Zinsco / GTE Sylvania panelboards. It operates on 240V three-phase systems and features a thermal-magnetic (Magnatrip) trip mechanism that protects circuits from overloads and short circuits. It belongs to the QFB series and uses a bolt-on mounting design, providing a secure electrical connection to the panel bus. Standard specifications confirm a 125A rating, 3 poles, and 240V operation with an approximate interrupt rating of 10 kAIC.

Applications:

The Zinsco QFB24 breaker is commonly used in commercial and industrial electrical systems requiring 125A three-phase protection, such as distribution panels, motor control centers, large machinery, and feeder circuits. It is specifically intended for legacy Zinsco bolt-on panelboards and is primarily used today for maintenance or replacement of existing installations rather than new builds.

Technical Specifications:

• Manufacturer: Zinsco / GTE Sylvania
• Model / Part Number: QFB24 / QFB24-125-3 / QFB243125
• Product Type: Molded Case Circuit Breaker (Bolt-On)
• Poles: 3-Pole
• Current Rating: 125 Amps
• Voltage Rating: 240 VAC
• Phase: 3-phase
• Mounting: Bolt-on (QFB series)
• Trip Type: Thermal-magnetic (Magnatrip)
• Interrupt Rating: ~10 kAIC @ 240V
• Terminals: Lug connections
• Function: Overcurrent and short circuit protection
• Status: Obsolete / discontinued (commonly refurbished or surplus)

Common Replacements:

• Square D QOB3125 3-Pole 125A Bolt-On Circuit Breaker
• Siemens BQD3125 3-Pole 125A Bolt-On Breaker
• Eaton BAB3125H 3-Pole 125A Bolt-On Brea