House Electrical Wiring: Importance Of Testing For Ground

If you are dealing with house electrical wiring and wish to check whether or not your home is properly grounded, begin by testing the receptacles.

Check whether they have two or three wires.

If a receptacle is missing a grounding terminal, it clearly is not grounded.

If a two- or three-wire plug adapter is employed, unless the house has armored cable and metal boxes, the appliance is probably still not grounded.

In this case, the receptacle won't be grounded unless it is an automatic grounding receptacle, which has a spring clip on one of its attachment screws.

This clip grounds the receptacle to any grounded metal electrical box.

Standard receptacles are not approved for such automatic grounding.

However, if the electrical box is grounded back to the main panel by means of armored cable, then you can install a standard three-pronged receptacle and connect its grounding terminal to the metal box.

A plug-in receptacle analyzer checks grounded outlets for correct/incorrect house electrical wiring.

Three neon bulbs light up in various combinations to indicate correct wiring, open ground, open neutral, open/hot, hot/ground reversed, or hot/neutral reversed.

To test whether an existing three-pronged terminal is grounded, use a plug-in circuit tester.

Never assume that a three-pronged receptacle is grounded.

If the ground is missing, the light sequence on the tester will indicate as much.

The ground may even be properly connected at the receptacle but disconnected farther down the line.

Common grounding problems that occur at or near the main electrical panel include grounding connections made to rusted rebar or pipe, cut or loose grounding wires, or improper connectors on a grounding rod.

Be sure that the clamp used on your rod is a listed (approved) connector, which must be cast bronze, brass, or plain or malleable iron.

A heat-welded connection is also acceptable (NEC Section 250.70).

The grounding rod itself, if iron or steel, must be at least 5 inch in diameter.

Stainless-steel and nonferrous metal rods must be at least 8 inch in diameter [Section 250.52(A)(5)].

The use of improper materials may lead to corrosion and result in a high-resistance connection.

A two or three-wire plug adapter cannot ground an appliance if there is no grounding path to the main panel; it merely permits the appliance to be plugged in.

A short to the appliance in your house electrical wiring may cause a severe shock or electrocution.

For more information about house electrical wiring visit ask the builder.com.

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