I don't think the lights actually dim that much! The arc flash is so bright that the camera doesn't even register that tiny wall light any more. That's a normal effect with automatic exposure controls.
The fuses are likely gL Diazed but without knowing how many amps it's pointless to speculate. What I can tell you is that gL and gG fuses are fairly slow. Depending on their size they're supposed to trip at 1.6 to 2.1x rated current within an hour! The overload factor is larger with smaller fuses, 1.6 is only from 20 A up I think.
