Electrical installations include all electrical equipment used for the production, conversion, distribution or use of electrical energy.
Electrical installations are classified as follows, according to the highest of the nominal voltages, existing either between any two of their conductors, or between one of them and Earth:
1° Very low voltage area (abbreviated as VLV): installations in which the voltage does not exceed 50 volts in alternating current or 120 volts in smooth direct current;
2° Low voltage area (abbreviated as LV): installations in which the voltage exceeds 50 volts but does not exceed 1,000 volts alternating current or exceeds 120 volts but does not exceed 1,500 volts direct current;
3° High voltage area A (abbreviated as HTA): installations in which the voltage exceeds 1,000 volts without exceeding 50,000 volts in alternating current, or exceeds 1,500 volts without exceeding 75,000 volts in smooth direct current;
4° High voltage B range (abbreviated HTB): installations in which the voltage exceeds 50,000 volts in alternating current or exceeds 75,000 volts in smooth direct current.
For currents other than smooth direct currents, the voltage values given in the preceding paragraphs correspond to rms values.