Protective Measures Against Electrical Hazards

These measures are designed to protect individuals from electrical hazards. They can be implemented at the facility or personal level. Protection must be provided against direct contact (accessible parts or insulation failure) and indirect contact from arcing. Measures must also be taken to prevent power surges or over-current, high voltage drops, burns due to overloading, etc.

Protection Against Direct Electrical Contacts

These measures are designed to prevent the risk of contact with live parts (according to Standard 20460-4-41):

• Protection by insulation of live parts: This must be an insulator that can only be removed by destroying it; lacquer varnish is not sufficient.
• Protection by barriers or enclosures: All equipment and connections must be located in enclosures or behind barriers having a minimum degree of protection IP XXB, according to UNE 20324. This prevents people or animals from touching live parts.
• Protection through local obstacles: This is used in electrical service areas. The obstacles may be removable without tools or keys but should prevent inadvertent disassembly. They should prevent accidental contact but do not have to prevent intentional contact.
• Protection by placing out of reach: This is used in electrical service rooms where live parts are located outside the accessible volume of people (whose limits cannot be reached by hand without aids).
• Supplementary protection with residual current differential devices: This involves the installation of leakage protection devices (30 mA).

Protection Against Indirect Electrical Contacts

This protection is achieved by applying some of the following measures:

• Automatic power cut-off protection: Under the connection system, the facility produces cuts (TN or TT) using differential protection, or it is immune to the first cut (IT): TN system, TT system, IT system.
• Use of Class II equipment or equivalent insulation: Such protection is ensured by:
  • Using equipment with double or reinforced insulation (Class II).
  • Factory-built sets having equivalent insulation (double or reinforced).
  • Additional insulation assembled during the electrical system installation to isolate electrical equipment having only basic insulation.
  • Reinforced insulation mounted during the electrical system installation to isolate exposed live parts when it is not possible to use double insulation.
• Safety in non-conducting locations:

  The masses and the active parts must be located so that two different masses cannot be touched simultaneously, or a mass and any conductor. There is no provision for a protective conductor. The following should be observed:

  • • • Remoteness from the masses and the conductive elements.
      • Interposition of effective obstacles.
      • Isolation or isolated placement of the conductive elements.