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|  DSH 432
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# U0 V) K1 J! T2 I! o: D( L& Z | Protective Impedance versus no-load voltage% }: v! X O. s$ c' m" n7 ^4 K
| 18f)
8 g+ w4 L7 x3 j3 B. A) _9 `3 I' X: ?9 ` | 60601-1(ed.2);am1;am2
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# b6 q9 m3 P! eStandard(s)- (year and edition):
. M" H" F" f" L' e8 n3 Y) @" MIEC 60601-1:1988 Ed.2 Am1+Am2
, S2 }; U' m! ^, _- FSub clause(s): 18f)
/ G' l- k5 u3 N& e- S3 ]6 wSheet n°: DSH-4320 L r( o) R j t
Subject: Protective Impedance versus noload voltage! G7 I, j. Q9 w y
Key words: Protective, impedance, earth, connection, no-load0 x- s; [6 F( h
Confirmed by CTL at its 39th meeting, in Cologne8 ?' X# e. Z4 B; J
Question:
, e! V* P' S; z M7 D, J$ }/ BEQUIPMENT for example having a rated current of 30 A require a test current of 1.5 times 30 A.
8 }/ n. l. R; C, U, _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: G: B# p+ C! B* I3 Q) m) g/ N3 B
in contradiction to the required no-load voltage of 6 V maximum.' f. f- f2 q7 | A& p
Decision:
1 F0 q1 e; |! b: A `8 D2 H2 uMeasuring the protective earth connection has in fact two reasons. It is to determine impedance
+ l! O! \0 i' z1 B5 f8 m- y; Pand cross-sectional area of protective earth connections. For a measuring current of 25 A both! X' M7 `: Y, Y, h/ W
can be done with one measurement. Requiring a measuring current of more than 25 A it shall be6 @( P$ x* j( U# k. T
splitted up into two measurements. In this case, the impedance shall be determined first, using a
' E; ?, {/ k4 t8 P1 G% i( Jvoltage not exceeding 6 V.
% p2 N9 e- I; Y6 i) T* T6 _If cross-sectional area of the protective earth connections cannot be determined as equal to the m3 Q3 Z0 x' a# w5 @
one for the phase by measurement of the area, then measurement with current shall be from a
5 U# e7 K5 J% W y1 `: Xsource with a higher voltage than 6 V.
; u1 U9 w, q- E0 O' x# g+ j! p. L# k
7 e, U/ P% x ]& _/ O2 Y8 D T t( l2 G3 o1 B: b
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