标题: OSMEE 14-2 [打印本页] 作者: chinatown 时间: 2017-1-8 17:32 标题: OSMEE 14-2 本帖最后由 chinatown 于 2017-1-8 17:36 编辑 w+ E: b b* {1 {: b( p G* x. S7 ^/ g/ ~. _" q6 b
Standard:1 h/ X8 u: A: v7 U* Q
EN 60950-1:2005+A1+A11+A12+A21 \! |1 e) [7 U, g
$ K- w. Y4 w0 h+ \Question:7 y9 m' y9 I0 l( Z2 G# i
1. Should a SELV-supplied equipment generating hazardous voltage inside the enclosure, not accessible to the operator, be classified as Class III?. Q: S. j% H- z5 f" Q( O8 z1 H9 V
2. What kind of equipment can be unclassified?3 ~) c! e# i8 E! i! {
3. Can unclassified subassemblies be used in class III equipment?4 e4 V3 q, H* V1 d8 C- G
Proposal for Decision: OSM EE conclusion: decision only in the minutes 3 c1 u* R& `3 H" L0 v, C j1. No, Class III shall not contain hazardous voltages irrespective of safety measures or means provided to prevent access.8 e, P4 q& }( R- T5 X2 h+ O# J
2. Only Class ll equipment needs to be identified as such. Any other equipment needs no classification. Subassemblies need not be classified. # U- T# ^, w) O3. A class III equipment can contain unclassified subassemblies, provided that they do not generate hazardous voltages in the particular application. ; ^0 V6 n; t8 k! g+ rExplanatory notes:' a8 T. B; V; F6 _
1. See “Class III equipment” and “Hazardous voltage” definitions below:4 n0 A- T. d. P- G( k. e, `
1.2.4.3 3 G2 ~7 v: u) `# bCLASS III EQUIPMENT . r; w) F7 S( x; `( X6 P1 aequipment in which protection against electric shock relies upon supply from SELV CIRCUITS + J4 K! r* |* k2 B3 Tand in which HAZARDOUS VOLTAGES are not generated8 S/ E5 D$ ?) |* W& L, s
NOTE For CLASS III EQUIPMENT, although there is no requirement for protection against electric shock, all other # i" T. b! O- E, W% T; \6 urequirements of the standard apply. " y9 h* c3 z( A! j2 o7 X1.2.8.6" @0 T8 Y Y" `9 s' @' T
HAZARDOUS VOLTAGE / x i$ M( a4 C( r" xvoltage exceeding 42,4 V peak, or 60 V d.c., existing in a circuit that does not meet the 4 A4 Q4 W- K; n% Crequirements for either a LIMITED CURRENT CIRCUIT or a TNV CIRCUIT, M7 m9 e8 K& n: @
2. Some equipment used for telecommunication, example radio base stations, are supplied by batteries or power supplies supplying non hazardous voltages. However they do generate hazardous voltages inside. If the equipment fulfill all requirements in the standard but does not fit in any class it can be unclassified./ [* O& y; T' A: ^5 x, R* V. N/ [
Comments from TC108 MT2 meeting in Stuttgart November 2013: + e$ g3 a% n: I, `- gQ1: agree . `! L$ n% q, D) Q9 i6 l4 \+ bQ2: only Class ll equipment needs to be identified as such. Any other equipment needs no classification. Subassemblies need not be classified." \% Q' q9 S$ e; g% ?
Q3: OK Refer also decision 91/17[attach]110507[/attach] 4 ~ @+ p" c! y: E0 e# W5 H: [$ ~+ t* i; _1 x
[attach]110507[/attach]6 Z. J& |: g4 ~. ?; k9 m/ j0 i