3.6 Prospective touch and step voltages
3.6.1 Prospective touch voltages – special locations
3.6.2 Prospective touch voltages – frequented locations
3.6.3 Remote locations
3.6.4 Prospective step voltages
3.6.5 Testing and maintenance of earthing systems
3.6.1 Prospective touch voltages – special locations
Lines operating at voltages less than or equal to 66kV should comply with the requirements of curve A1 of Figure 2.
Lines operating at voltages greater than 66 kV should comply with the requirements of curve A2 of Figure 2.
3.6.2 Prospective touch voltages – frequented locations
Lines operating at voltages less than or equal to 66kV should comply with the requirements of curve B1of Figure 2.
Lines operating at voltages greater than 66 kV should comply with the requirements of curve B2 of Figure 2.
Figure 2: Touch Voltage versus Fault Duration
3.6.3 Remote locations
Aside from ensuring positive primary protection operation, it is not necessary to make specific provisions for limiting prospective touch and step voltages on exposed conductive parts. However, in the case of However, in the case of pole-mounted equipment that may be operated from the ground in remote locations, you should consider limiting step and touch voltages to the levels recommended for frequented locations.
To protect workers working near exposed conductive parts in remote locations, special operating procedures such as temporary earth rods or portable equipotential mats and gloves may be used.
3.6.4 Prospective step voltages
Prospective step voltages should not exceed twice the value of the prospective touch voltage determined for the corresponding location as outlined in the sections, Prospective touch voltages – special locations and Prospective touch voltages – frequented locations.
3.6.5 Testing and maintenance of earthing systems
All earthing systems should be tested periodically to ensure the earthing system integrity.
Adequate records of all earthing system tests should be maintained.
Last updated July 22, 2005
Other languages