I wired the 02660 emergency light in the "emergency only" (SE) mode, but it only flashes twice and doesn't turn on in a power outage, why?

Check that the 2 switches in the battery compartment are set to ON. Selector 1: Enable the battery (battery ON = enabled, 1 = battery is not enabled). Selector 2: Set the lighting time during a power failure (ON=1 hour at 100% brightness, 1 = 3 hours at 30% brightness).