If you have ever stood on a wet basement floor and been jolted with a good, strong electrical shock, you have participated in a live demonstration of how electrical current seeks the shortest route to the ground.

At that moment you received the shock, the electrical current used you as the conductor; wire is much better choice.
When a short crops up in your wiring or in a device that is connected to it, your best bet is a properly grounded circuit.

There are several bits of background information you should know in order to minimize the chance of shock and electrical shock, and even damage from lightning.

First, let’s distinguish between two different kinds of grounding.
System grounding is the grounding of current carrying wires.
Equipment grounding is the grounding of non-current-carrying portions of your wiring installation, such as the frames of motors or appliances, as well as smaller metal items such as conduit, armored (BX) cable, and boxes for fixtures, switches, and receptacles.

Proper grounding begins in the service panel at the grounding bus bar, which is connected-literally-to earth by a cable known as a ground wire. This is fastened either to a metal rod driven into the earth outside your home or to your incoming water supply- line. The bus bar, in turn, has solderless connectors or screw terminals to which two other types of wires are connected-grounding wires and grounded wires.

Grounded wires are the white neutral wires that complete each of your circuits by returning current to its source, and in so doing, ground the system. (Also connected to the bus bar is the incoming neutral wire coming from the utility company.)

Grounding wires-usually bare, green, or green with yellow stripes- are the ones that ground the system.

One example will explain why it is so important to have an equipment ground. If a short circuit should crop up inside a motor, there is a chance that the motor would continue to run and that the fuse or breaker would not react. The frame of the motor could then become “live” and anyone touching the live frame could complete the circuit through his or her body into the ground. A properly installed grounding wire would have routed that errant current safely back through the bus bar and into the ground.

There are two basic ways to obtain a good equipment ground, depending on the type of wiring you have. For circuits with individual wires strung inside metal conduit or armored (BX) cable, the conduit or cable must be mechanically connected to each box and to the service panel. A tight connection ensures proper grounding. Where nonmetallic-sheathed cable is used, the cable must contain three wires-a hot, a neutral, and a bare grounding wire. The grounding wire must extend from the metal switch or outlet box to the bus bar. In many older homes, neither of these situations exists.