Earthing Design

Earthing mats are more in line for reducing step potential but no so much for the actual earthing of the system.

There will be times when it is not possible to bury earthrods and as such earthmats can be used.

Is that what you are looking for a earthmat?

A ground (earth) mat or grounding (earthing) mat is a flat, flexible pad used for working on electrostatic sensitive devices. It is generally made of a conductive plastic or metal mesh covered substrate which is electrically attached to ground (earth). This helps discharge any static charge which a worker has built up, as well as any static charge on tools or exposed components laid on the mat. Application may fall into computer room or substation (where the grating is electrically connected to the equipment. This is to ensure that the feet and hand of operator have the same potential).

So, as you can see that the purpose of earth mat is to protect static discharge and reinforce the higher level of safety for people when working with high volatge in substation.

Earth rods are different kind of earthing (grounding) where multiple rods are buried in the ground and they are welded together to achieve the earthing (grounding) resitance requirement. It is the most common earthing in the world.

While the earth rods are required in all type of buildings or facilites. The factor may be the safety level and type of application (sensitive or high voltage equipments) that determine the type of earthing.

Hello Kebian,

My interpretation of your question and answer would be as follows :-

As 'Piefaces' reply states the use of either earthing rods or earth mats is determined to a large extent by where you wish to locate them - soil or rocky ground!

The depth to which you would drive a earthing rod or bury an earth mat also depends on the conductivity of the soil at that location.

The requirement for the choice between earth rods and mats is further determined by the conductivity of the soil plus the calculated fault current that you would expect the earthing system to carry.

The connection of multiple rods/mats can also also be arranged where they are connected in star or delta to improve the earthing reading in difficult areas or areas where greater protection is required such as fuel dumps etc.

Earthing remains a complex problem because too many installations are carried out where the bare minimum earthing is installed (cost considerations or lack of technical knowledge?) and my suggestion to you would be to source further information detailing the exact requirements and methods involved in earthing. Alternatively you could look at a specialist earthing design/installation company in your area that has the required engineering expertise and experience.

Please do not resort to what I have come across where the earthing rod is located beneath a dripping tap to overcome a poor earthing problem.

Hope this helps to answer some of your questions!

Wy don't you start with IEEE 80?

electricalexpert65:

Could you recheck my comment if it conform to IEEE 80? Because some of it are from Wiki...

You could be correct. Earth mats can also be used for Static Discharges. But, what the OP has asked for is about Earth Mats used in EHV Switchyards, to reduce the Step Potential & Touch Potential hazards. This is covered in IEEE 80.

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