Tom Bellemare said:
If I remember correctly, it takes less than a 1/4 amp to kill a human. The smallest breaker that is common is 15 amps.
It actually can be as low as 30 to 60 milli amps. Fuses that are rated at 15 amps are meant to prevent a short circuit (which can start fires), not an electrocution.
To prevent an electrocution you need a RCD or GFCI as it's named in North America. A fuse detects an amp overload, that's why it's rated at a certain threshold. An RCD detects a difference in the current that's send and the current that returns. When you get electrocuted, the return value is different from the sent value because of leakage to the ground (through you).
But it's not the current OR the voltage that kills, it's a combination of both. They are always connected to each other.