FAQ - Earthing

1. According to DIN 18014, when does one need a ring earth electrode and when a foundation earth electrode?
Foundation earth electrode:
For all new buildings because a foundation earth electrode is required according to DIN 18015, the current technical connection conditions of the power supplier and the future connection rules AR4100.

Ring earth electrode:
When the earth electrode in the foundations (foundation earth electrode) does not have sufficient contact with the earth. As a rule this applies to building waterproofing, i.e. foundations with increased earth contact resistance like, e.g. a white tank, perimeter insulation, foam glass gravel

2. Why do the connection points on the ring earth electrode have to be wrapped in insulating tape if V4A material is used?
Connection points in the soil are generally a weak point - in terms of corrosion and when high quality material like V4A is used. This is why the standard (DIN 18014) says that these should be wrapped in insulating tape.

3. What is the right mesh size for ring and foundation earth electrodes?
The maximum mesh size for both foundation earth electrodes and ring earth electrodes is 20 m x 20 m.
However, in combination with a lightning protection system the mesh size for the ring earth electrode must be 10 m x 10 m. To keep your options open with regard to retrofitting a lightning protection system, it is advisable to opt for a mesh size of 10 x 10 m with ring earth electrodes.

4. Does one always need a ring earth electrode with a lighntning protection system?
No. According to DIN 18014, the earthing system required for a lightning protection system can consist of either a ring earth electrode or a foundation earth electrode. The lightning protection system must then be erected according to Part 3 for the EN 62305 lightning protection standard.

5. What are the distances from the ring earth electrode and foundation earth electrode to the edge of the building?
The gap required between the ring earth electrode and the building is at least 1 metre and it should be buried at least 0.8 m deep. The foundation earth electrode should be installed as a closed ring in the floor slab at the outside edge of the foundations sheathed in at least 5 cm of concrete.

6. What about buildings with individual foundations?
Individual foundations require an earth electrode of at least 2.5 m in length. The individual foundations must be interconnected using corrosion-resistant earthing materials V4A - preferably in direct contact with the earth. If waterproof concete is used in the individual foundations, a ring earth electrode must be fitted.

7. Is it always necessary to mount earth rods?
No earth rods are required for the standard configuation of the foundation or ring earth electrode. Earth rods should be used as an alternative measure if it is not possible to install an earthing system which conforms with DIN 18014.
In this case, earth rods with a length of at least 3 m can be installed round the building as an additional measure to the ring earth electrode. The best position for these is the corners of the building. The distance between the earth rods may not exceed 20 m if there is no lightning protection system and 10 m with a lightning protection system. The earth rods must be connected to the ring earth electrode.

8. Why does one need a functional bonding conductor and a ring earth electrode?
According to DIN 18014, a functional bonding conductor is required in the concrete foundations in addition to a ring earth electrode because it is here that the internal equipotential bonding of the building structure (reinforcements, metal constructions, etc.) is established. The functional bonding conducter should be connected to the reinforcements every 2 m and to the ring earth electrode every 20 m (if lighnting protection is required, every 10 m).

9. The customer has a mixture, e.g. white tank + individual foundations + floor slab (for example, a warehouse with part concrete floor slab and part paving).
How can one comply with the standard here?

As a general rule, the design chosen here is based on waterproof concrete. This means that a ring earth electrode must be installed under the floor slab and also under the white tank. This is connected to the functional bonding conductor of the floor slab and that of the white tank.

10. Semi-detached/terraced house with a "white tank" instead of a strip foundation. What does the earthing look like here?

DIN 18014 describes earthing systems for foundations with increased earth contact resistance. Here, one requires the configuration of the ring earth electrode with functional bonding conductor in the foundations with appropriate connections (see Lightning Protection Guide, page 132). In practice, a ring earth electrode with cross connections around the semi-detached houses has proven effective as the foundation slab is usually cast in one piece. The ring earth electrode should be connected to the functional equipotential bonding at the intersections.

A - Connection to the external lightning protection
B - Connection to the MEB
C - Funtional equipotential bonding
D - Ring earth electrode
E - Connection of ring earth electrode with the functional equipotential bonding

11. How often does the ring earth electrode have to be connected to the functional equipotential bonding. How often does a terminal lug need to be led to the surface?
If there is no lightning protection system a connection between the functional equipotential bonding and the ring conductor is required every 20 m (depending on the circumference of the building). If a lightning protection system exists, a connection is made with every down conductor. In our experience, the most favourable design comprises the connection of the functional equipotential bonding with the ring earth electrode and a terminal lug to the surface every 10 m. This makes retrofitting a lightning protection system (up to class of LPS II) a simple matter.

12. Waterproof concrete (white tank), what kind of wall bushings are required?
Pressure-tight earthing wall bushings, e.g. Part No. DEHN + SÖHNE 478530, tested with an air-pressure of 5 bar in compliance with DIN EN 62561-5. The pressure-tight wall bushing should lead into the service entrance room, to enable simple connection of the installation level.

13. Can the ring earth electrode be made of V2A?
No! The standard insists on the use of corrosion-resistant material, e.g. V4A, material number 1.4571 or, alternatively, copper wire for laying in the ground.

14. Why connect the ring earth electrode and the functional bonding conducter?
If there is a direct lightning strike nearby, there may be dangerous flashover, step voltages and electromagnetic interference. For this reason, the two systems need to be connected to one another. The reinforcements should be connected to the functional bonding conductor at least every 2 m.

15. Are the terminal lugs for external lightning protection systems also made of V4A?
As a basic rule, it is advisable for the terminal lugs in the external lightning protection system to be made of V4A. However, according to DIN EN 62305-3, it is also possible to use other materials like, for example, galvanised material with additional corrosion protection (in the transition are between the soil and a

16. From what depth does the soaked, frost-free area start for the ring earth electrode?
Earth electrodes should be laid at a depth of at least 0.8 m to guarantee the necessary soaking and, in winter, the corresponding frost depth.

17. How should functional equipotential bonding be established with a fibre concrete slab?
Fibre concrete is often used for the foundation slabs of industrial buildings. A mesh size of 10 x 10 m should be maintained for the ring earth electrode which is, in this case, in the soil below the fibre concrete floor slab or below the blinding layer. If extensive data and automation technology is employed in the building, the mesh size should be reduced to 5 m x 5 m.

18. How should a building with individual foundations, partial basement and foundations with a wooden construction be equipped according to DIN 18014?
Please refer to question no. 9

19. From which quality is concrete classified as waterproof?
Although waterproof concrete soaks up water, the water does not penetrate all the way through the concrete even after longer periods of time. This means that there is no damp on the inside of the wall. According to DIN EN 206-1/DIN 1045-2 a water penetration depth of 50 mm may not be exceeded for waterproof concrete. This is usually achieved for waterproof concrete at a minimum compression strength class of C25/30. At the same time, the water/cement ratio must be less than 0.6 and the minimum cement content greater than 280 kg/m³.

You could not find the answer to your question? E-mail our technical support.

Have you got any questions? Contact us.

Technical support

T. +49 9181 906 1750

Stuur een e-mail

Topic buildings

Results for products (0)

Results for content (0)

FAQ - Earthing

Have you got any questions? Contact us.