When it comes to the mechanics of a house, especially the interaction of electricity, it is always best to turn off the main breaker switch which cuts off all electricity to the house. But that does not mean that the novice should tinker with anything, it just means you won't get electrocuted when the power is out.
In every breaker box, there are normally a larger double switch, or main switch, that shuts down power to the entire unit. If that main master switch is off, there will be no power to the entire unit it serves. That still does not mean you should do your own repair work. It only means you can prevent yourself from being killed if power goes out.
In every breaker box, there are normally a larger double switch, or main switch, that shuts down power to the entire unit. If that main master switch is off, there will be no power to the entire unit it serves. That still does not mean you should do your own repair work. It only means you can prevent yourself from being killed if power goes out.