|
− First letter: relationship of the power distribution system to earth;
: v" p' {3 |+ nT means direct connection of one pole to earth,/ G2 \- J) [4 ^! U
I means system isolated from earth, or one point connected to earth through an) I+ r) }$ ]3 d i/ G
impedance.
. S7 D! b1 M3 F7 n0 y8 b− Second letter: earthing of the equipment;
7 O0 l: N# o+ QT means direct electrical connection of the equipment to earth, independently of the) q0 W- s' G0 o2 Y% P8 K ^1 ~9 J n V
earthing of any point of the power distribution system,
# B; r& b1 j) h5 A: a* aN means direct electrical connection of the equipment to the earthed point of the power
( o7 C# `1 h" M/ x mdistribution system (in a.c. systems, the earthed point of the power distribution system
% M6 I2 I5 F* _* H. ?* P* ^5 {3 Iis normally the neutral point or, if a neutral point is not available, a phase conductor).
8 D E7 {% _3 z# I− Subsequent letters if any: arrangement of neutral and protective conductors;+ X* `" I ~0 h3 ^# y* U
S means the protective function is provided by a conductor separate from the neutral or
1 w \ w3 n5 `4 xfrom the earthed line (or in a.c. systems, earthed phase) conductor,4 E: _% ]$ O) U! _$ p/ _
C means the neutral and protective functions are combined in a single conductor3 M$ b8 y6 K9 w* u3 |
(PEN conductor).$ w* h. W7 F' _8 u0 x% h* u, V
--`,,`````,,,````,,`,,,``,,,,,`-`-`,,`,,`,`,,`--- |
|