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|  DSH 4328 e" h3 T4 a$ q' q
r4 a" H3 r' F4 ?* @+ n% `! i
| Protective Impedance versus no-load voltage
% b0 [- ^1 z: `4 ?0 k. l: W | 18f)
& s9 `3 W+ { e* P6 Y7 t3 I | 60601-1(ed.2);am1;am2
9 M* f( K$ r8 Z |
1 j' H) n& B0 _, a1 X! z& u aStandard(s)- (year and edition):
7 c0 f" V* E( P9 C( BIEC 60601-1:1988 Ed.2 Am1+Am2/ {* M$ Q& b; s/ s0 B6 o
Sub clause(s): 18f)! ~, C' ^% t. j) _
Sheet n°: DSH-432
, i* G& K: D6 [Subject: Protective Impedance versus noload voltage
4 T0 g' A) J$ x) o2 H( h/ @Key words: Protective, impedance, earth, connection, no-load
7 c; b) m/ _% @3 J% GConfirmed by CTL at its 39th meeting, in Cologne1 e) B8 n0 Z; D4 U, g
Question:" @" e& ]# G3 n( u, I
EQUIPMENT for example having a rated current of 30 A require a test current of 1.5 times 30 A.: f+ q8 m7 F3 W) T! o
With a maximum impedance of 0.2 W the voltage drop has to be 9 V (0.2 W * 45 A = 9 V). This is
7 W: i3 v! }( E/ o% A' X2 c/ Bin contradiction to the required no-load voltage of 6 V maximum.7 I' {0 u, w$ c) q
Decision:# E m( X5 \5 H, K9 x0 Q' y
Measuring the protective earth connection has in fact two reasons. It is to determine impedance( q2 R2 a( O5 z
and cross-sectional area of protective earth connections. For a measuring current of 25 A both
K. c& s1 r# scan be done with one measurement. Requiring a measuring current of more than 25 A it shall be
3 `' S8 \0 h3 k* c7 rsplitted up into two measurements. In this case, the impedance shall be determined first, using a
1 N1 r( I, ~7 R5 Ovoltage not exceeding 6 V.
, E r( i8 X& b) a' G4 JIf cross-sectional area of the protective earth connections cannot be determined as equal to the2 v; \# X* \8 ^" X# M
one for the phase by measurement of the area, then measurement with current shall be from a x$ I. v5 t% }* ?2 h
source with a higher voltage than 6 V., X2 h- R, r( R
4 a; v$ u9 @) A" y1 y( p( t. N* x- N7 ~ z7 ^5 T8 `: ?
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