Electrical Grounding

Grounding is the connection of all parts of a wiring installation to the ________ or to other systems that are connected conductively to the earth.

Identify the colour wires used for electrical grounding

• Red

• Yellow

• Black

• Green

• Blue

Identify the two types of electrical grounding systems

• Receptacle grounding

• Appliance grounding

• Equipment grounding

• Device grounding

• System grounding

Look at the diagram. Why does the grounding wire protect him from a severs electric shock?

• Most of the dangerous current will travel through the wire because the resistance of the wire is more than the resistance of his body.

• Most of the dangerous current will travel through the wire because the resistance of the wire is less than the resistance of his body.

• The voltage in the circuit is large

• The voltage in the circuit is small

Identify all the three qualities of a good grounding system.

• It must be able to dissipate high fault current repeatedly

• It must be of a low electrical resistance

• The material used must be of a high resistance

• It must be of a good corrosion resistance

• The material used must be flexible

In system grounding The Service Entrance (neutral wire) is connected to the ground so that excessive voltage and accompanying overcurrent would be directed to ground.

• True

• False

The letter which shows system grounding is _____

Equipment grounding is Bonding the grounding conductor to equipment enclosures and metallic noncurrent-carrying equipment.

• True

• False

The colour wire used for equipment grounding is _____

Common methods of grounding an electrical system includes:

• Cables or wires (minimum 8AWG)

• Metal plate which are buried at least 30” below ground level

• Galvanized or copper rods driven 8’ into the ground for contact with the moist earth

• Reinforcing bars (structural steelwork buried into the ground)

• Metallic water piping system of 10’ or more in length (at least 30” below ground level)