|
− First letter: relationship of the power distribution system to earth;
: H" z: E& V) A: ?/ q; ?T means direct connection of one pole to earth,8 E4 w7 X1 v! ~8 Z; e% i0 X- n$ `
I means system isolated from earth, or one point connected to earth through an" c1 H6 k) B7 b( q0 F
impedance.3 g7 P4 m+ V& i# f/ J+ \
− Second letter: earthing of the equipment;
; O; z. x$ h, S7 ET means direct electrical connection of the equipment to earth, independently of the! L. N% E7 B9 c5 c" A7 e+ A
earthing of any point of the power distribution system,
) [( g6 T4 ^: bN means direct electrical connection of the equipment to the earthed point of the power6 [8 \2 Q5 l* k4 A; l
distribution system (in a.c. systems, the earthed point of the power distribution system# Q- A T- R. g( s" ~& F
is normally the neutral point or, if a neutral point is not available, a phase conductor).
0 X/ Q! d; I' | P2 @% J1 w5 ?− Subsequent letters if any: arrangement of neutral and protective conductors;
% Q1 K$ k' p# i2 R' DS means the protective function is provided by a conductor separate from the neutral or- J1 \# V; s( i; t$ O
from the earthed line (or in a.c. systems, earthed phase) conductor,
& B4 t1 [2 p( F& T0 u9 vC means the neutral and protective functions are combined in a single conductor
! ?* k" T$ ]3 y. }8 ]+ P(PEN conductor).
C ^! H, `* C, ]& D' d--`,,`````,,,````,,`,,,``,,,,,`-`-`,,`,,`,`,,`--- |
|