Thomas Edison invented the circuit breaker in 1879; although it did not come into widespread use in industrial applications until the 1920s, it is reasonable to assume that the Titanic had fuses, not circuit breakers (although if evidence of circuit breakers on the Titanic can be provided, I am willing to stand corrected). Having said that, water and electricity are an odd couple. Freshwater, although it does conduct electricity to a degree, is not as good a conductor as seawater due to the dissolved minerals in the water. With that in mind, even though the circuits would short out, lights would remain lit for a time until they came in contact with the seawater. At that point, the heat on the glass's inside and the 28-degree Fahrenheit seawater on the outside would make the bulbs break, and they would go out. Eventually, the fuses would blow, but even then, electricity would not be shut off because of the conductivity of the seawater. Also, the electricity will flow along the surface of the water, not to any great depth in the water.
There is an old saying among electricians (and among amateur radio operators when they repair or modify their equipment): "It's the volts that jolt and the mils that kill." In other words, the voltage will shock you, but the amperage determines if you get killed. Also, the electrical current will flow along the surface of the water, not under the water. This raises an interesting question, Why were there no reports of people standing in the water as the ship sank, getting shocked? IIRC, Titanic ran on 100 Volt DC current, but what was the amperage, or power, behind the current?
