Reference norms


There are several IEC (Comitato Elettrotecnico Italiano) Standards and Guides that regulate earthing systems, depending on whether these are low voltage, high voltage, or lightning protection systems. The most important reference standards and laws are:

  • Standard IEC 64-8 ‘Electrical consumer systems with a rated voltage not exceeding 1000 V alternating current and 1500 V direct current’
  • Standard IEC 11-1 ‘Electrical installations with a voltage greater than 1 kV alternating current’
  • DM 22 January 2008, no. 37 ‘Reorganisation of the legislative provisions on the installation of electrical systems in buildings’
  • DPR 462/01 ‘Procedure for reporting installations and devices for protection against atmospheric discharges, earthing devices for electrical installations and hazardous electrical installations’
  • Law no. 81 of 9 April 2008 ‘Implementation of Article 1 of Law no. 123 of 3 August 2007 on the protection of health and safety in the workplace’
  • Guide IEC 64-12 ‘Guide for the execution of the earthing system in buildings for residential and tertiary use’
  • Guide IEC 11-37 ‘Guide for the execution of earthing systems in energy-using systems powered at a voltage greater than 1 kV’
  • Standard IEC 81-5 ‘Lightning protection components’

Components for LPS are also tested for resistance to environmental corrosion and subjected to an impulsive electrical test with a 10/350 μs waveform.

Two test classes are planned:

  • Class ‘H’ = 100 kA (10/350)
  • Class ‘N’ = 50 kA (10/350)

The components are chosen based on the level of protection and the expected lightning currents.


External lightning protection and LPS

The materials used for earth-termination systems subject only to the application of IEC 64-8; V2 differ due to the materials used in earth electrodes for LPS, as shown in the tables below. Terminals and conductors must comply with EN 50164 and be dimensioned in relation to the lightning currents expected from the level of protection at the point where they will be installed.

1. Table – Materials, configurations and minimum cross-sections of earth lead-in rods and down conductors

2. Table – Materials, configurations and minimum dimensions of earth electrode elements



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