Siemens / Murray MP2100 Miniature Circuit Breaker

Yes. Siemens acquired Murray and has phased out the Murray brand name. The Siemens Q2100 (Type QP) is the officially UL-listed, direct replacement for the Murray MP2100 (Type MP-T).

This 2-pole miniature circuit breaker requires two standard 1-inch spaces in a compatible load center.

Yes, Siemens and Murray Type MP and QP breakers are backward compatible with many older ITE EQ-P load centers. Siemens acquired ITE and maintained the same physical plug-on design. Always verify the panel label for Type EQ-P or QP compatibility.

Yes, this 100A breaker can be used as a back-fed main in compatible Siemens or Murray load centers. However, the National Electrical Code requires it to be permanently secured to the bus bar using an approved hold-down kit, such as the ECMBR1.

The LI designation stands for Long-Time and Instantaneous trip functions. The long-time function protects your wiring against sustained overloads, while the instantaneous function trips the breaker immediately in the event of a severe short circuit.

No. While it might physically snap into some competitor panels, the MP2100 is only UL-listed for use in approved Siemens, Murray, and legacy ITE load centers. Using it in unapproved panels violates electrical codes and voids the safety listing.

The 10,000 Ampere Interrupting Capacity (10kAIC) indicates the maximum fault current this breaker can safely interrupt without failing. This is the standard rating for most residential applications, but you must verify that your local utility fault current does not exceed this value.

No, the terminal lugs on the MP2100 are rated for both copper and aluminum conductors ranging from 8 AWG to 2/0 AWG. If using aluminum wire, applying a specialized antioxidant joint compound is highly recommended to prevent corrosion.