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IEC

Extract From: IEC  364ELECTRICAL  INSTALLATION  OF

BUILDINGS

CHAPTER 54 Earthing arrangement and protective Conductors542(1980)

542.2      Earth electrodes

542.2.1     The following types of earth electrodes may by used:

        –           earth rods or pipes:

        –          earth tapes or wires :

        –          earth  plates:

       –          earth electrodes embedded in foundations:

       –          metalllc reinforcement in foundations:

Note- special care should be exercised wbere the construction includes pro- stressed concrete.

     Metallic water- pipe systems under the conditions 0f Subclause542.25

Other suitable underground structures (see also Sub –clause 542.2.6).

     

    Extract From: IEC 1024 Protection of structures against lightning 

1-3 Renforced concrete struytures

      Neelwork within rcinforced concrete structures is considered to be electrically

Continuous provided that it fulfils the following conditions:

4P1– 4-3 (British Standard) BS

Extract from:BS Code of Practice 7430 (formerty CP1013) EARTHING

 

PRITISH  STANDARD                 bs7430:1991

Code of Practice for

Earthing 

(Formerly  CP1013: 1965)

11.Structural steelwork ready made and effective earth electrode .  The total electrode area formed by the underground metalwork of large structured can provide an earth resistance lower than that obtainable by other methods. Overall values well below 1 W are obtainable.

The resistance to earth of concrete encased steelwork or of conrete reinforcing bars will vary according to the type or soil and its moisture content and the design of the foundation.Concrets is hygroscopic and, except in dry locations.Can be of about 30 W m to 90 W m at normal temperatures , Which is lower than lower than that of some types of soil.

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