Darkening or blinking lights are one sign of an electrical problem. Because light fixtures typically draw very little power, dimming or flickering is almost never caused by an issue with the lamp itself. The problem is more likely to be with your electrical wiring. A washing machine drawing current to heat water could cause dimming if it is on the same circuit. Consult an electrician if you want to move lights to different circuits or install dedicated lines for large appliances.
The presence of sparks from your outlets is never a positive sign and could indicate a problem with your wiring. Call an electrician immediately if a breaker panel, fuse box, or outlet starts sparking. A sparking appliance, on the other hand, may indicate that the fixture itself is damaged, in which case you should contact an appliance repairman.
Tripped breakers or blown fuses are another sign of wiring that requires professional attention. To prevent overloading, circuit breakers and fuses are built to trip. If a vacuum cleaner or hair dryer consistently trips a breaker no matter where you plug it in, the appliance is most likely to blame. However, if using a single outlet causes you to repeatedly blow the same fuse, the circuit is most likely overloaded. Speak with a professional about updating the circuit or installing a new line.