Zinsco Q243070 70 Amp 240 Volt Circuit Breaker

Description:

The Zinsco Q243070 is a 3-pole 70 Amp molded case circuit breaker designed for use in Zinsco / GTE Sylvania panelboards. It operates at 240 VAC and uses a thermal-magnetic (Magnatrip) trip mechanism to provide protection against overloads and short circuits. This breaker belongs to the Q24 (Type Q) series and typically features a plug-in mounting style, though equivalent QB versions are bolt-on. It is part of a legacy product line that is now discontinued.

Applications:

The Zinsco Q243070 breaker is commonly used in industrial and commercial three-phase electrical systems, including distribution panels, motor control centers, and machinery circuits requiring 70A protection. It serves as a branch or feeder breaker for equipment such as motors, compressors, and pumps. Due to its age, it is now obsolete and generally available only as surplus or refurbished units.

Technical Specifications:

• Manufacturer: Zinsco / GTE Sylvania / Challenger
• Model / Part Number: Q243070 / Q2430-70
• Product Type: Molded Case Circuit Breaker
• Poles: 3-Pole
• Current Rating: 70 Amps
• Voltage Rating: 240 VAC
• Phase: 3-phase
• Interrupt Rating: ~10 kAIC @ 240V
• Trip Type: Thermal-magnetic (LI – long-time & instantaneous)
• Mounting: Plug-in (Q series) / Bolt-on (QB series)
• Status: Discontinued / obsolete

Common Replacements:

• Square D QOB370 3-Pole 70A Bolt-On Circuit Breaker
• Siemens BQD370 3-Pole 70A Bolt-On Breaker
• Eaton BAB3070H 3-Pole 70A Bolt-On Breaker