1. The Necessity of Protective Measures against Hazardous Contact Voltage
The protection of human life, health and capacity for work is a
basic human concern. Therefore, in electrical plants with or without earthed net
point, it is necessary to take protective measures against hazardous contact
voltage if the conductor-earth voltage exceeds
- 50 V with alternating current or
- 120 V with
Accidents due to electricity are often caused by improper
installation or missing and/or defective protective measures.
Manufactures of electrical equipment are obliged to insulate
this equipment for the respective working voltage.
Why is it still necessary to take protective measures, even if
cables, electrical equipment and plants are sufficiently insulated?
The protection of man against hazardous contact voltage has
priority over function!