(introduction...)

These are subdivided in two groups.

Group 1: Protective measures preventing the development of hazardous contact voltage.

- protective insulation
- protective low voltage
- protective isolation
- protective conductor system

Group 2: Protective measures which prevent that hazardous contact voltage continue to exist.

- protective earthing
- connection to neutral
- fault-voltage protective system
- fault-current protective system
- isolating fault-current protective system

If the protective measures are categorized with respect to the presence of a protective conductor, the following subdivision results:

Protective measures "without" protective conductor

- protective insulation
- protective low voltage
- protective isolation

Protective measures "with" protective conductor

- protective conductor system
- protective earthing
- connection to neutral
- fault-voltage protective system
- fault-current protective system
- isolating fault-current protective system

Technical terms recurring with the individual protective measures have to be used according to Figure 3:

- contact voltage (1)
- fault-voltage (2)
- fault-current (3)
- body resistance between current entry and exit points (4)
- transition resistance of the station point (5)
- resistance of earth (ground) (6)
- resistance of earth bus (7)

Figure 3 - Fault-current circuit - 1 contact voltage, 2 fault voltage, 3 fault current, 4 body resistance between current entry and exit points, 5 transition resistance of station point, 6 resistance of the ground, 7 resistance of earth bus