Siemens / Murray MQJ3125 Molded Case Circuit Breaker
- 125A
- 3 Pole
- Unit Mount
Quantity
Siemens / Murray MQJ3125 - 125A 3 Pole Molded Case Circuit Breaker
New
Quantity
Description
A drop-in solution for commercial facilities, the MQJ3125 delivers 125A of overcurrent defense. This 3-pole MCCB utilizes fixed thermal and magnetic trip elements to handle standard electrical faults. Mounting into legacy Murray and Siemens panelboards, it eliminates the need for retrofitting. It serves as the predecessor to the QJ23B125, maintaining exact physical dimensions for older enclosures. With a 10kAIC rating at 240VAC, it includes common trip functionality and is HACR certified.Specifications
| Brand | Siemens / Murray |
|---|---|
| Series | MQJ |
| Amperage | 125A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC |
| Frame Type | MP |
|---|---|
| Terminal Type | Lugs |
| For Use With | Murray and Siemens Load Centers, Metering Equipment |
| Wire Gauge | 6 AWG - 300 kcmil (Cu), 4 AWG - 300 kcmil (Al) |
| Max Wire | 300 kcmil |
| Min Wire | 6 AWG (Cu), 4 AWG (Al) |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Alarm Switch, Padlock Attachment |
|---|---|
| Accessories | Load Side Lugs |
| Standards | CSA C22.2 No. 5, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Non-Interchangeable Trip, Common Trip |
Product FAQs
6 answersWhat is the direct replacement for the legacy Murray MQJ3125?
The Siemens QJ23B125 is the official direct replacement for the MQJ3125. It maintains the exact physical dimensions and QJ frame specifications, allowing it to drop into older enclosures without aftermarket adapters.
What panels and equipment are compatible with the MQJ3125?
This breaker is designed for legacy Murray and Siemens load centers, as well as compatible metering equipment like Siemens Power Mod meter stacks that accept QJ-frame bolt-on breakers.
Does the MQJ3125 feature common trip functionality?
Yes, this 3-pole breaker features an internal common trip mechanism. An overcurrent or short circuit on any single phase will simultaneously open all three poles to disconnect power safely.
Is the MQJ3125 HACR rated?
Yes, this breaker is HACR certified. It is approved for use with heating, air conditioning, and refrigeration equipment that requires this specific overcurrent protection rating.
Can the trip settings be adjusted on the MQJ3125?
No, this breaker features a non-interchangeable thermal-magnetic trip unit with fixed long-time and instantaneous trip functions. The trip settings cannot be adjusted in the field.
How does the MQJ3125 mount into the panel?
It utilizes a bolt-on connection to secure directly to the panel bus. This provides a rigid and reliable connection suitable for commercial and industrial power distribution systems.
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