grounding equipment and method

8/10/2019 Grounding Equipment and Method

1/23

GROUNDING EQUIPMENT

AND METHODS


2/23


3/23


4/23


5/23


6/23

Based on Dalziels Formula:

Human Fibrillation Threshold is: 164 mA or 0.164 Amps

So,


7/23


8/23


9/23


10/23

The best safety precaution

is to respect/consider that all

equipment as if it couldbecome energized.


11/23

1. Charges induced on the line by a neighboring energized line

Source of Hazards

2. A fault caused by an accidental contact on flashover between the

line and neighboring energized line.

3. Induced static charge due to atmospheric conditions.

4. An error in which the line is accidentally energized

5. A lightning strike to the line.


12/23

Protection to Personnel

The means of providing personnel protection

may take several forms. These may includethe insulation or isolation of workers,

provision of an equipotential zone around the

workers or provision of a low resistance path

to ground to induced charges or faultcurrents and limit touch and step voltages to

a safe level.


13/23


14/23


15/23


16/23


17/23


18/23


19/23

Electromagnetic

Induction

- Occurs when angrounded open

conductor picks up an

induced voltage from an

energized lineparalleling or

perpendicular to the

line.


20/23

Grounding Devices

All grounding devices must be sized to carry the largest fault current tobe encountered for a time period long enough to allow the line

protection system to operate.

Grounding devices include the following:

1. Personal grounds2. Master grounds

3. Structure base grounds

4. Running grounds

5. Grid grounds

6. Ground rods


21/23

Grounding System Considerations

1. Care of grounding equipment

inspection should be made prior touse grounding equipment to check for loose or dirty connections,

broken wire strands and seized clamps.

2. Grounding conditions the effectiveness of various ground sources

will vary depending on the equipment to be grounded. So, it mustbe determined first what particular ground to be implemented in a

certain area.

Warning guy wires should not be used as ground source.

3. Cleaning of Connections all surfaces to which a grounding clamp is tobe cleaned to ensure proper contact since grounding systems

depends on a low resistance path.


22/23

5. Ground Grid Application all grid conductors and ground rods mustbe interconnected and all equipment, structures, anchors, metallic

pulling lines, conductors and overhead ground wires within the area

should be bonded to the grid.

4. Grounding Application grounding cables must be connected to the

ground source first, then to the object being grounded. Whenremoving grounds, the ground must be removed from the grounded

object first and then from the ground source.


23/23

end

grounding equipment and method

Documents