High Voltage

The high voltage term refers to the electrical circuits wherein the voltage utilized is the cause of the specific insulation requirements and safety concerns.High voltage is utilized in the electrical power distribution, in the cathode ray tubes in order to produce particle beams and X- rays, for ignition, to demonstrate arcing, amplifier vacuum tubes and photomultiplier tubes and various other scientific and industrial applications. The mathematical or numerical definition of the high voltage   generally depends on the situation of the discussions.  The two factors considered in the categorization of the high voltage are the probability of causing the spark in air and the hazard of the electric shock by proximity and contact. The definitions might refer either to the voltage between the two conductors of a system, or between any ground and conductor.  In high voltage electric transmission engineering, the high voltage is generally considered by voltage more than 35,000 volts.  This is the classification which is based on the design of the insulation and apparatus.

The IEC (International Electrotechnical Commission) and its national counterparts (Institution of Engineering and Technology, Institute of Electrical and Electronics Engineers, VDE Association for Electrical, etc.)describe the high voltage circuits which has more than 1000 Volts for alternating current and no less than 1500 Volts for the direct current and differentiate it from the low voltage (120 to 1500 volts Direct current and 50 to1000 Volts Alternating Current) and extra low voltage or ELV (Lesser than 50 Volts Alternating Current or Lesser than 120 Volts Direct Current) circuits. This is in the framework of building wiring and the safety of the electrical apparatus.

Voltages m ore than 50 V  could generally cause hazardous or high amount of electricity or current to flow  via a human touching two points of the circuit, therefore safety standards usually are more restrictive where the probability of contact with such dangerous voltage circuits exists.

Questionnaire:

• What is high voltage?