|
|
|  DSH 492
% W) c) K& D" \, ]
& Q. c- n' A+ l. m2 q2 t2 ` | Protection against access to live parts
$ C1 Y, C) n5 X5 C1 d | 8.1.4
3 j( N% a, j5 S" g% v$ c3 Z/ T( S | 60335-1(ed.3), ?6 P* @, \' g7 L: b
|
$ `/ s( G l$ S! C; W2 D2 Y+ w
Standard: IEC 60335-1:1991, 3rd Ed.& O* S; I1 v0 Y' q. u0 c9 O/ o
Sub clause: 8.1.41 D5 I0 F/ F- w0 h* w' R
Sheet No. DSH-492
; ?/ C7 o9 s; v+ E- W5 oSubject: Protection against access to live parts2 h! W4 r( H% r0 n0 ^( [$ [
Key words: - Functional earthing
; g5 u0 s$ u% a' Q6 i, pDecision taken at 40th CTL meeting 20039 B8 F- z5 f# ?' S- {6 o3 Q
Question: h3 C( F" H' S( Y
Is functional earthing for the secondary circuit of SELV transformers permitted?
; p9 q6 Y, U! G+ ARationale:- Z% ~) \# _# O; [
See question.7 x! ~9 q8 I6 g( K+ Y& V/ \' |
Decision:
2 N0 t' x- {. R. o( a" X8 k1) Earthing of secondary circuits of SELV transformers (PELV circuits) is acceptable in* j: `; q3 ]3 m1 d5 |+ p6 |
general except when SELV is specifically required by the standard for a specific circuit (for) s' [1 m, P, p+ F* Q: J
example in whirlpool baths), in which case earthing of the secondary circuits are acceptable
; b/ i7 v) Z4 \. a9 ?if:
! i2 L9 _- C; f, O9 ca) the accessible parts of the secondary circuits are separated from the protective earthing0 I, ^1 m- {, w% |) y2 s4 B
circuit by at least protective impedance, or4 w8 t* e8 { u1 @# H) l
b) the accessible parts of the secondary circuits are either directly connected to the protective
( d1 e) m: |. Q) J0 h5 R- Bearthing circuit or are protected against accidental contact by insulation as specified for Class
: C1 B$ p( A5 M& l* ^III appliances or constructions, in particular the insulation shall be capable of withstanding a& D- _0 i% H* r+ `' ]8 J1 Q m* W
test voltage of 500 V AC for 1 min.. t, P X# L% h) u( Z9 E
Accessible parts directly connected to the protective earthing circuit shall comply with the: S. V' _4 r: O# F8 Q) d
requirements for protective earthing (see sub-clause 27.5) or shall be separated from live
: K: u9 b3 n& R! |( Z/ Cparts of the supply with insulation as specified for Class II construction.& X5 @- V/ H$ g- F- ^& J
2. See also the following figure.8 v4 x! F/ C& S E* u
8 L" }! @$ [- b7 l0 d3 ~' o5 {7 Q" Q* U1 a; m' ^) T! g
4 ?) h2 r" t" e0 A) r7 _, a/ Q6 B$ r6 \; }4 s2 N; a0 k0 d
|
本帖子中包含更多资源
您需要 登录 才可以下载或查看，没有账号？注册安规
x
|
1/2 
|关于安规|小黑屋|安规QQ群|Archiver|手机版|安规网
( 粤ICP13023453-10 ) 
窥视卡
雷达卡
发表于 2012-9-11 11:56
提升卡
置顶卡
沉默卡
喧嚣卡
变色卡
抢沙发
千斤顶
显身卡