Review on ⚡️ High-Performance Siemens Q2020 120V Breakers by Andrew Spainhour

The QT2020 circuit breaker is a CTL (Full Circuit Restriction) circuit breaker and can only be mounted in specific locations on the circuit breaker panel - typically the bottom 4 slots in the cabinet. The bar at these lower locations has cutouts to accommodate a CTL switch (and a standard switch). These switches have "locking tabs" that prevent them from being installed elsewhere and thus limit the total number of circuits that can be installed in the panel. What really adds to the confusion is that there is a "NON-CTL" version of this switch (QT2020NC) without the "lockout" feature, and I've seen it at Lowes with the same barcode and part number. HODO stocks the QT2020NC and charges over $24 for it, compared to over $9 for the CTL version. See the images to show the difference between the CTL and non-CTL versions of this switch. The bottom line is that even if the label on your switch panel says it accepts QT switches, they only fit in a few specific slots. If these slots already have standard-width switches, you must shuffle the switches so that these switches can be placed in the CTL-style slot. This is not an issue with the QP or QT panel, just the location of the CTL or non-CTL slot within that panel.