6
TN-C-S system: one part the system neutral and protective function are combined a
single conductor, another part the system there are separate neutral and protective
conductors.s.
Figure 5.
.c.2., r.c.2.
b) Conventional voltage limit
The conventional voltage limit equal a. 120 ripple-free d.FUNDAMENTAL RULES FOR PROTECTION AGAINST ELECTRIC SHOCK 41
L1, L2, Phase conductors 1,2,3
or Line conductors 1,2,3
PE Protective conductor;
N Neutral conductor;
PEN PEN conductor.
Symbols for conductors according IEC 617 (1983):
protecctive conductor (PE)
neutral conductor (N)
PEN conductor (PEN)
5.2 Measures for protection automatic disconnection supply
For all types systems earthing following fundamental principles shall applied:
a) Earthing
Exposed conductive parts shall connected the earth means protective conductor. the
maximum prospective touch voltage which can occur exposed conductive parts under usual
conditions for indefinite time.m.2
