Siemens / Murray MQJ2100 Molded Case Circuit Breaker
- 100A
- 2 Pole
- Unit Mount
Quantity
Siemens / Murray MQJ2100 - 100A 2 Pole Molded Case Circuit Breaker
New
Quantity
Description
Designed for robust commercial and residential power distribution, this 100-amp unit-mount MCCB features non-interchangeable thermal-magnetic trip elements. It integrates seamlessly into legacy Murray and Siemens metering equipment or load centers. Delivering a 10kAIC interrupting rating at 240VAC, this QJ-frame device is the exact predecessor to the modern QJ22B100, ensuring facility managers can maintain older switchgear with confidence and proper code compliance.Specifications
| Brand | Siemens / Murray |
|---|---|
| Series | MQJ |
| Amperage | 100A |
| Poles | 2 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC |
| Phase | 1 |
| 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
8 answersWhat enclosures and panels are compatible with the MQJ2100?
This bolt-on breaker is designed for use in legacy Murray and Siemens load centers, as well as modular metering equipment that accepts QJ or QR frame breakers. Always verify compatibility with your specific panel wiring diagram.
Why is the Murray MQJ2100 often cross-referenced with Siemens breakers?
Siemens acquired the Murray brand and eventually phased it out entirely. As a result, Murray QJ frame breakers like the MQJ2100 share the same physical footprint and internal components as their Siemens QJ counterparts.
What is the modern Siemens replacement for the MQJ2100?
The direct Siemens equivalent is the QJ22B100. Because the entire QJ frame series has been superseded by the QR frame, the current active replacement is the QR22B100. Installing a newer QR frame breaker in an older QJ panel may require a retrofit mounting kit.
What are the acceptable wire gauges for the MQJ2100 lugs?
The factory lugs accommodate 6 AWG to 300 kcmil copper conductors, or 4 AWG to 300 kcmil aluminum conductors.
What trip functions are included in the MQJ2100?
It utilizes a fixed thermal-magnetic trip unit with Long-Time and Instantaneous (LI) functions. This provides standard protection against both gradual overloads and sudden short-circuit faults.
Does the MQJ2100 use a plug-on or bolt-on connection?
This is a unit-mount, bolt-on circuit breaker. It must be bolted securely to the bus or mounting assembly, which is typical for larger frame breakers in commercial panels and metering equipment.
Can I install a newer Siemens QR breaker in place of the MQJ2100 without modifications?
Not always. While the QR series replaced the QJ series, the physical dimensions differ slightly. You will typically need a specific Siemens mounting kit to safely adapt a QR breaker into a legacy QJ or MQJ space.
What is the maximum fault current interrupting rating for this breaker?
The MQJ2100 has a maximum interrupting rating of 10kAIC at 240VAC. If your system requires a higher fault current rating, you will need a high-interrupting variant within the QJ or QR family.
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