Siemens Q24040CT2NC 40/40A Quadplex Miniature Circuit Breaker

The NC designates a Non-CTL (Circuit Total Limitation) breaker. It lacks a rejection clip on the bottom, allowing it to be installed in older legacy Siemens, ITE, or Murray panels that do not have notched bus stabs for tandem or quad breakers.

This quadplex breaker condenses four poles of protection into a two-pole footprint, requiring only two standard one-inch panel spaces to provide two independent 240V, 40-amp circuits.

Yes, this Siemens non-CTL quad breaker serves as a direct replacement for the legacy Murray MP24040CT2 and MP24040CT2NC models.

The breaker features independent common trip mechanisms for both the inner and outer pairs. If an overload or short circuit occurs on one leg of a 240V circuit, both poles for that specific circuit will trip simultaneously, leaving the other 40-amp circuit unaffected.

The terminals are rated for 8 to 6 AWG copper conductors or 8 to 4 AWG aluminum conductors. Ensure wires are stripped to the correct length and torqued to the specifications printed directly on the breaker label.

Modern Siemens panels are typically CTL-rated and require breakers with rejection clips, such as the standard Q24040CT2, in designated tandem slots. The Q24040CT2NC is specifically engineered for older panels that do not restrict tandem placement. Always verify the approved breaker types listed on your panel door label.