CheckSP Services supply problemYour internal wiring problem
Neighbours' lightsAlso off or also flickeringAll normal
HDB lift lobbyLights offLights on
Your corridor / street blockBlock darkBlock lit normally
Your main switch (the big one)Cannot be turned back on, or trips immediatelyTrips because of an internal overload, but a partial reset holds for a while
Time of failureOften affects many units at once, sometimes after a storm or an SP maintenance noticeJust your unit, no pattern with weather or SP works