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| DSH 394A5 @/ @: X( c2 b- v$ a
9 X: w7 k/ f! q+ h( I; k9 G2 ]
0 p6 l+ D/ K4 W+ _2 O( h+ S+ J0 [ | Touch current for equipment having multiple supplies supplying power simultaneously- Y( o% B' a6 y. `' m6 l- B
| 5.1.2, last paragraph / 5.13 b4 p D& Y$ b. M; \
| 60950-1(ed.1) & 60950(ed.3)
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Standard(s):; E U; Q6 M/ T
IEC 60950 (1999) 3rd Ed." R8 x3 \7 C6 {$ }
IEC 60950-1 (2001) 1st ed.( n J @# M0 }: [, T8 }: d
Sub clause(s):( I9 {0 ?. r5 ]" \! u: W
5.1.2, last paragraph
7 \2 ^3 D0 r# Z7 k) ~5.1
0 Z/ k" q) H' iSheet n°: 394A
- d' f0 B [) c) c! E6 mSubject:
$ _ ~( T+ J- jTOUCH CURRENT for equipment
T, b0 s) g! ?% x0 [1 }having multiple supplies supplying
: u" J2 A+ x" @5 S f" Xpower simultaneously
0 v5 q4 p/ d) s+ MKey words:2 c. p4 C o2 |& X7 I0 u3 }
- TOUCH CURRENT for equipment
* ^0 }; \/ r5 b7 b0 @; G; lwith multiple supplies8 E5 o' O0 w5 _
Decision taken at the 41st
1 i7 S# Y' `- I- D$ s: MCTL meeting 2004. This& H. A5 L" K q% U3 V g! _
decision replaces n. 3947 z9 f) e0 p; Z+ f3 H" i: A6 }
taken at the 39th CTL0 b; E: q1 s5 k" q* x
meeting 2002
0 [& r* J- E; Z8 d+ r fQuestion:2 w1 M: M6 K# X8 G
1. Should the TOUCH CURRENT be measured for each individual supply source to determine if the3 C4 d5 x6 U$ m) R5 y% T* A- h2 h
PROTECTIVE CONDUCTOR CURRENT exceeds 3.5 mA and if it does exceed, then require PERMANENT
8 {3 }0 t# I9 ^5 O4 f4 a4 Oor PLUGGABLE TYPE B connection to the supply and meet 5.1.7?) X0 p# E0 Y& R
2. Should the cumulative TOUCH CURRENT be measured to determine if the total TOUCH CURRENT
. @; @+ K, @- q* h# zexceeds 3.5 mA? If the total TOUCH CURRENT does exceed 3.5 mA then require that AC MAINS3 ]5 q$ Z/ g$ e7 }8 ^: |! l: j
SUPPLY to be connected to separate AC MAINS SUPPLY circuits with at least one source having a
7 U8 l7 [7 {! { qreliable connection to PROTECTIVE EARTH (e.g. be PLUGGABLE TYPE B or PERMANENTLY
. [ d; G7 ~) g: _6 C+ }connected EUT?
' @( h9 x/ U2 R, Q) D1 s8 RRationale:
8 v; b4 [9 k. a. j- vPLUGGABLE EQUIPMENT TYPE A does not have a reliable connection to building PROTECTIVE EARTH. Therefore, if
, W, g7 ^, t% Wthe TOUCH CURRENT measurement exceeds 3.5 mA, then that particular source needs to be PERMANENTLY
% c3 h* R8 o# \, u; {- h, dconnected or have a PLUGGABLE TYPE B connection to PROTECTIVE EARTH. In older buildings, EARTH may
2 e: ]( w- _, G0 P* h# K6 ~6 @not be present on the PLUGGABLE TYPE A socket outlets on the wall. The multiple connection does not help, as all
+ Q9 [; ~# D' y d: ]; ]such socket outlets may not have EARTH connection. Therefore, if the individual or cumulative PROTECTIVE+ n7 F9 K/ d8 }0 Y+ O( E& H
CONDUCTOR CURRENT exceeds 3.5 mA, then at least one of the sources needs to be PERMANENTLY connected or
9 p, L. u1 O% {# ehave a PLUGGABLE TYPE B connection to PROTECTIVE EARTH. If one of the sources is required to be1 h( A5 Z* u9 {7 z8 v
PERMANENTLY connected or have a PLUGGABLE TYPE B connection to PROTECTIVE EARTH in order to
- p/ e: X6 m8 r. a7 F0 R M7 jcomply with the TOUCH CURRENT requirements, the equipment shall be provided with both a marking on the equipment
6 R v- a1 y4 `$ R$ Dand a statement in the installation instructions, specifying that the USER is to disconnect all power sources connection
$ a6 u3 g& W u1 P# [% Mbefore disconnecting the PERMANENT connection or the PLUGGABLE TYPE B connection+ M2 d- y0 M- F% ^' X; f
Decision:: r* y- K' H8 d/ @
See copy of the CDV for IEC 60950-1 2nd edition on Page 2# Q& v1 L2 ]8 K' A5 {
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