The green dashed line shows the normal path for current to flow. Notice the grounding electrodes for making an electrical connection with the earth ground. To use the US National Electrical Code ...

If there is a fault that causes the casing of the device to become live, a large current will flow through the low-resistance earth wire. This high current will cause the fuse to melt. Once the ...

Grounding is important to protect against electric shocks; the third line redirects electric current during ... and stopping the flow of electricity during a ground-fault condition.

This means that current can only flow in the other direction. This is the graph of current against voltage for a diode. Normally a diode will not conduct until a particular voltage is reached.