|
− First letter: relationship of the power distribution system to earth; X. \4 _, i" a8 e" O
T means direct connection of one pole to earth,
9 ?: N, i. v+ [6 ^7 j9 }! OI means system isolated from earth, or one point connected to earth through an- ^( q3 q. C( h- u1 ]1 B7 j8 M) |
impedance.
8 M0 f7 J) j M# L. e− Second letter: earthing of the equipment;
$ ]. K7 R( [. K9 U" wT means direct electrical connection of the equipment to earth, independently of the# K# x" [8 s, h% {9 Q
earthing of any point of the power distribution system,
, ^$ c" r4 G) G3 JN means direct electrical connection of the equipment to the earthed point of the power
3 H% U) E, g% ^9 i. t- w0 ~: P3 jdistribution system (in a.c. systems, the earthed point of the power distribution system4 l+ _) b( A0 R* e! a3 c. T
is normally the neutral point or, if a neutral point is not available, a phase conductor).! n# Y1 h9 s* j$ b6 a' r! \- H
− Subsequent letters if any: arrangement of neutral and protective conductors;
- ^( T0 C" X/ n& ]6 `; w( k: j; VS means the protective function is provided by a conductor separate from the neutral or
6 V6 Y' Z$ J9 J/ ?2 bfrom the earthed line (or in a.c. systems, earthed phase) conductor,
0 q3 \2 ^3 P; j+ D- xC means the neutral and protective functions are combined in a single conductor' e$ {' s1 @) H4 ]- I. G. A
(PEN conductor).
9 r8 | p! n, f9 D( K7 }* S J1 ^ S" W! n--`,,`````,,,````,,`,,,``,,,,,`-`-`,,`,,`,`,,`--- |
|