Lightning Protection Systems (Part 3 of 3) - Earth Termination System by Kingsmill Earthing

By Chris Dodds on 18th December, 2014

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Lightning Protection Systems (Part 3 of 3) - Earth Termination System by Kingsmill Earthing

Basic Overview Of A Lightning Protection System

Part 3 of 3  - Earth Termination System

Kingsmill Guest Blog for T&D by Jason Leatherland, UK Sales & Business Development Manager.

Part 1 Air Termination System - Risk Assessment & Air Termination Components & Important Remarks

Part 2 Down Conductor System – Design, Uses, Clamps & Important Remarks

 

Earth Termination System

  • The Earth Termination Network is responsible of discharging the lightning current through the surrounding ground mass. Therefore the energy of the lightning is dissipated in the ground.
  • To have an effective earth termination network the resistance value should read 0

 

Pictured: Earth Termination System

Earth Termination System

Earth Termination System Material

 

​Copperbond Earth Rods

  • Made from a low carbon, high tensile strength (600n/mm² minimum) steel core with a coating of molecular bonded 99.9% pure electrolytic copper. 250microns : minimum.
  • Earth rods usually provide the most cost effective earthing system due to the steel core.
  • Available in 16mm and 20mm earth rod diameter.
  • Standards to BS EN 50164-2, BS7430.

Pictured: Copperbond Earth Rods

Copperbond Earth Rods

Solid Copper Earth Rods

  • Material is Solid Copper.
  • Solid Copper Rods are useful where soil conditions are more aggressive as they have a high resistance to corrosion.
  • These earth rods have a tapped hole at each end which allows them to be joined together by means of a coupling dowel.
  • Kingsmill Solid Copper Rods are available in 15mm, 16mm, 20mm and 25mm.
  • Standards to BS EN 50164-2, BS7430.

Pictured: Solid Copper Earth Rods

Solid Copper Earth Rods

Stainless Steel Earth Rods

  • Made from austenitic steel to British standards.
  • The stainless steel rod is similar to copper rods but are more anodic than copper and are useful where galvanic corrosion is possible.
  • The current carrying capacity of the stainless steel rod in relation to copper is poor.
  • These earth rods have a tapped hole at each end which allows them to be joined together by means of a coupling dowel.
  • Can be supplied in different grades if required.
  • Standards to BS EN 50164-2,BS 7430.

Pictured: Stainless Steel Earth Rods

Stainless Steel Earth Rods

Concrete/Plastic Inspection Pits

  • The inspection pit protects the earth rod connection and makes it available for inspection. The pit can have an earth bar fitted diagonally in slots provided for multiple connections.

Pictured: Concrete/Plastic Inspection Pits

Concrete/Plastic Inspection Pits

Earth Rod Seals

  • Earth rod seals are used in case earth rods should penetrate a water proof membrane, the seal prevents water from flowing up through the earth pit.
  • This applies when earth rods cannot be installed outside the structure where the only place to install is at the lowest basement level
  • Earth rod seals can be single flange type or double flange type depending on the thickness of the main slab

Pictured: Earth Rod Seals

Earth Rod Seals

 

Lattice Copper Earth Mats

  • Earth mats are used in harsh soil conditions where the soil resistivity is relatively high. It is also used in rocky soil where earth rods cannot penetrate the ground.
  • Earth mats are used in conjunction with soil conditioning agents such as Bentonite or Marconite where earth mats help in dispersing the lightning current in the ground while the soil conditioning agent preserve humidity for a long time to lower the soil resistivity.
  • Kingsmill Lattice Copper Earth Mats are available in the following dimensions; 
  • 600mm x 600mm x 3mm​
  • 900mm x 900mm x 3mm

​Pictured: Lattice Copper Earth Mats

Lattice Copper Earth Mats

Solid Copper Earth Plates

  • Kingsmill solid copper earth plates are used as part of an earthing network.
  • They provide a long lasting solution where earth rods are unsuitable.
  • Generally used as an electrode where significant amounts of fault current can be encountered

Pictured: Solid Copper Earth Plates

Solid Copper Earth Plates

Earth Termination System Important Remarks

  • Each down conductor must have its own earth electrode termination and the resistance to earth of the whole system must not be greater than 10 Ohms without taking into account bonding to other services. The most common terminations are rods driven into the ground. These should be a minimum of 9m for the whole system.
  • The individual earth electrodes are sometimes interconnected by a ‘ring conductor’ to help reduce the overall resistance. This should be at least 0.6m below ground level and preferably pass below incoming services. The ring conductor is made from copper tape or cable (aluminium is not permitted for use below ground) and also helps to provide potential equalisation at ground level, in addition to potential grading.
  • Aluminium material is not permitted for use below ground therefore is not used as part of the Earth Termination System



Category:  Earthing & Lightning Protection

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