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− First letter: relationship of the power distribution system to earth;
# n2 ]1 @1 @# v- U% L6 mT means direct connection of one pole to earth,
( m- m: ~, ?* n0 @ M1 rI means system isolated from earth, or one point connected to earth through an1 C7 A# C) }% q8 K* {
impedance.* Q+ ~" }0 e+ I4 S2 b
− Second letter: earthing of the equipment;
1 L/ Y8 I/ ?, ?) G6 u) A' o0 C3 `T means direct electrical connection of the equipment to earth, independently of the
. }) c$ p+ N- v$ Cearthing of any point of the power distribution system,
+ a& S8 z' L& ~& u( `N means direct electrical connection of the equipment to the earthed point of the power& V0 k0 M6 A9 Y0 z
distribution system (in a.c. systems, the earthed point of the power distribution system
1 C, w3 \( f# q1 i' [8 @' xis normally the neutral point or, if a neutral point is not available, a phase conductor).
3 e+ v* F: B1 k5 F, m4 O0 \: ?3 g− Subsequent letters if any: arrangement of neutral and protective conductors;
! x# O \6 ]' eS means the protective function is provided by a conductor separate from the neutral or
t D$ Y4 X) G6 Q& _8 a- Z* n$ Mfrom the earthed line (or in a.c. systems, earthed phase) conductor,
9 |- w8 s9 t5 Z+ X) R# x/ `* g9 I& _C means the neutral and protective functions are combined in a single conductor/ [; e; ^' E q+ d; B0 W% E2 x
(PEN conductor).
& Y- D6 c. j ^" I9 `( }--`,,`````,,,````,,`,,,``,,,,,`-`-`,,`,,`,`,,`--- |
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