Grounding

Metal boxes: In this arrangement both the receptacle and metal box are grounded. Ground wires are spliced together and attached with a pigtail to the box and receptacle. The grounding wire nut shown has a hole in its top that makes installing a pigtail easier.

In a system with metal boxes, the pigtail method is considered the most secure. Other methods also work well if installed correctly; one such method is a grounding clip that clamps the ground wire to the box.

If a house is wired with armored cable or conduit, there often is no ground wire. The cable connector joins the metal sheathing or conduit to the box to provide the path for ground.

Plastic boxes: Where plastic boxes are used, a ground wire typically connects to the receptacle only. Here, where wiring runs through this box to another box, a grounding pigtail connects to the device.

Old fixtures: Many older ceiling fixtures are not grounded. Recent codes, however, call for grounding. Connect the fixture's ground lead (usually a stranded wire) to the strap on a metal box or to a ground wire.

Old switches: Most older switches are not grounded; many switches do not even have a ground screw. Recent codes call for switches to be grounded. Replace an older switch with a newer one that has a ground screw and connect it to a ground wire.