Funny

American homes have a master circuit breaker (or fuse) which protects the entire house, and then individual circuit breakers for several circuits throughout the house, the exact configuration depends on the home, the era it was wired, etc. These only look at current. An American household 15 amp circuit breaker will happily electrocute a human if he only draws 10 amps. It doesn't care if the electricity is completing the circuit through ground, it's only job is to keep the wires in your walls from overheating and starting a fire.

Ground fault circuit interruptors (GFCIs) detect when current is completing the circuit through ground instead of neutral, which is what happens when you drop the proverbial toaster in the bathtub. Fresh water is an insulator but salty, soapy or acidic water is a conductor, and will conduct electricity into the pipes of the house, which are often used as the electrical system's ground. GFCIs are often installed in places where one might encounter the outdoors or plumbing, aka when there's a significant risk of a short to ground. A typical American duplex outlet costs a buck or two, a GFCI outlet costs upwards of $10, it's expensive to install a whole house with GFCIs.