Siemens Q1515 Twin 15-Amp Circuit Breaker — Type QT Tandem, 10 kAIC

The Siemens Q1515 twin circuit breaker fits two independent 15-amp circuits into the space of one, buying back panel slots in a load centre that's run out of room before it's run out of circuits. Type QT tandem construction stacks two single-pole 15-amp breakers in a single 1-inch footprint, so a finished basement or added lighting run doesn't force a subpanel just to land one more circuit. A calibrated thermal-magnetic mechanism handles both failure modes on each circuit: it rides out the slow heat of a sustained overload without nuisance tripping, then opens hard and fast on a dead short, with a 10 kAIC interrupting rating on a 120/240V service. The rejection feature seats it only in panel positions rated for tandem breakers — the physical guard that keeps a load centre inside its listed circuit count, rather than overfilled past what the panel label allows. CSA-certified and UL-listed, sourced through verified Siemens supply — not the refurbished or counterfeit stock that circulates on open marketplaces — it earns two circuits from a single slot and asks nothing further of it.