Siemens NSB-Q240 Miniature Circuit Breaker

Siemens NSB-Q240 Miniature Circuit Breaker is a 2-pole, 40 A plug-in breaker designed for residential and light-commercial panels, delivering 120/240 V AC service. Part of the Siemens QP family, the Q240 designation identifies a 40 A, two-pole unit with a standard-trip characteristic for reliable overcurrent protection in panelboards and load centers that accept QP/MP breakers. It carries a typical interrupting rating of 10 kA at 120/240 V, providing protection against short circuits in two-pole 240 V circuits. Use it to guard branch circuits feeding 240 V appliances or multiwire branch circuits in standard US electrical systems; its plug-in form factor simplifies installation in compatible Siemens panels and it is commonly listed for use with QP-type breakers in residential installations. The NSB-Q240 is designed for compatibility with Siemens' NSB/QP product line and common Siemens panels that accept QP breakers, offering a consistent protection scheme across Siemens low-voltage offerings while avoiding the need for non-standard devices. In short, this 40 A, 2-pole MCB provides dependable two-pole protection for 120/240 V circuits in homes and small businesses, enabling safe operation of 240 V loads such as water heaters, dryers, and air conditioning equipment when paired with the appropriate panel.