ZINSCO QB24-U 20A 240V 2-Pole Molded Case Circuit Breaker QB24U

Description:

The Zinsco QB24-U (commonly referenced as QB24-2020 or QB2420 variants) is a 20 Amp, 2-pole molded case circuit breaker designed for use in Zinsco / GTE Sylvania panelboards. It operates on 240V systems and utilizes a thermal-magnetic trip mechanism to provide protection against overloads and short circuits. This breaker belongs to the QB24 series and features a bolt-on mounting design for a secure connection to the panel bus.

Applications:

The Zinsco QB24-U breaker is commonly used in residential and light commercial electrical systems for 240V branch circuits such as small HVAC units, water heaters, pumps, and dedicated appliance loads requiring 20A protection. It is specifically installed in Zinsco bolt-on panels typically found in older electrical systems and is mainly used today for maintenance or replacement purposes.

Technical Specifications:

• Manufacturer: Zinsco / GTE Sylvania / Challenger
• Model / Part Number: QB24-2020 (QB24- U variant)
• Product Type: Molded Case Circuit Breaker (Bolt-On)
• Poles: 2-Pole
• Current Rating: 20 Amps
• Voltage Rating: 240 VAC
• Mounting: Bolt-on (QB series)
• Trip Type: Thermal-magnetic
• Interrupt Rating: ~10 kAIC @ 240V
• Function: Overcurrent and short circuit protection
• Status: Obsolete / discontinued (surplus or aftermarket replacements available)

Common Replacements:

• Square D QOB220 2-Pole 20A Bolt-On Circuit Breaker
• Siemens BQD220 2-Pole 20A Bolt-On Breaker
• Eaton BAB2020H 2-Pole 20A Bolt-On Breaker