ZINSCO QB24-2100 U 100A 240V 2-pole Molded Case Circuit Breaker QB242100

Description:

The Zinsco QB24-2100 U is a 100 Amp, 2-pole molded case circuit breaker designed for use in Zinsco / GTE Sylvania panelboards. It operates at 240V and features a thermal-magnetic trip mechanism that protects circuits from overloads and short circuits. This breaker belongs to the QB series and uses a bolt-on mounting design, providing a secure connection to the panel bus. It is equivalent to models such as QB2100 and is considered a standard high-capacity breaker for legacy Zinsco systems.

Applications:

The Zinsco QB24-2100 breaker is commonly used in residential and commercial electrical systems as a main or feeder breaker for subpanels, HVAC systems, large appliances, and distribution circuits requiring 100A protection. It is typically installed in older Zinsco bolt-on panels and is now primarily used for maintenance or replacement of existing equipment rather than new installations. 

Technical Specifications:

• Manufacturer: Zinsco / GTE Sylvania
• Model / Part Number: QB24-2100 U / QB2100
• Product Type: Molded Case Circuit Breaker (Bolt-On)
• Poles: 2-Pole
• Current Rating: 100 Amps
• Voltage Rating: 240 VAC
• Phase: Single-phase
• Interrupt Rating: ~10 kAIC @ 240V
• Mounting: Bolt-on (QB series)
• Trip Type: Thermal-magnetic (LI – long-time & instantaneous)
• Function: Overcurrent and short circuit protection
• Status: Obsolete / discontinued

Common Replacements:

• Square D QOB2100 2-Pole 100A Bolt-On Circuit Breaker
• Siemens BQD2100 2-Pole 100A Bolt-On Breaker
• Eaton BAB2100H 2-Pole 100A Bolt-On Breaker