ZINSCO QFB34150 U 150A 3P 240V Molded Case Circuit Breaker

Description:

The Zinsco QFB34150 U is a 150 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 trip mechanism to protect circuits from overloads and short circuits. It belongs to the QFB series and uses a bolt-on mounting design, providing a secure electrical and mechanical connection to the panel bus. Standard specifications confirm a 150A rating, 3 poles, and 240V operation with a typical interrupt rating of approximately 10 kAIC.

Applications:

The Zinsco QFB34150 breaker is commonly used in commercial and industrial electrical systems requiring 150A three-phase protection, such as distribution panels, feeder circuits, motor control centers, and heavy-duty equipment. It is specifically intended for legacy Zinsco bolt-on panelboards and is primarily used today for maintenance or replacement of existing installations.

Technical Specifications:

• Manufacturer: Zinsco / GTE Sylvania
• Model / Part Number: QFB34150 U (QFB24-150-3 equivalent series)
• Product Type: Molded Case Circuit Breaker (Bolt-On)
• Poles: 3-Pole
• Current Rating: 150 Amps
• Voltage Rating: 240 VAC
• Phase: 3-phase
• Mounting: Bolt-on (QFB series)
• Trip Type: Thermal-magnetic
• Interrupt Rating: ~10 kAIC @ 240V
• Function: Overcurrent and short circuit protection
• Status: Obsolete / discontinued (typically surplus or reconditioned)

Common Replacements:

• Square D QOB3150 3-Pole 150A Bolt-On Circuit Breaker
• Siemens BQD3150 3-Pole 150A Bolt-On Breaker
• Eaton BAB3150H 3-Pole 150A Bolt-On Breaker