PDSH 992 Extra safety circuit equivalent to SELV or double/reinforced insulation

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PDSH 992 / P; V# I+ |- F7 j5 M# I4 v $ z0 e  N7 z' u

Extra safety circuit equivalent to SELV or double/reinforced insulation " P& W- ^4 K) u3 J

12 # [$ n9 z, u8 Z/ H- i& E

60570(ed.3);am1;am2 & 60570(ed.4) " C1 m8 c' H* k

' H  i2 @: {+ P6 c1 n2 {( F( _Standard(s):
* C7 l3 S7 d2 E* S: L0 u  [! \  uIEC 60570 All editions
5 y( e5 @# C  ^0 y6 c7 ZSubclause(s): 12
6 N! [! Y6 d7 ]# O& C3 T% i9 b+ {No. Year PDSH 0992 2010
Category: LITE Developed by: ETF5 OSM/LUM
: z% U5 T7 a5 U3 Y) w" G' T3 QSubject:
# v8 H' p: S2 n4 r2 A- f1 e  D- ?Extra safety circuit equivalent to SELV or double/reinforced insulation
Key words:
; d& l- N1 _+ d; Z# v. Q3 n- SELV condition
- Electronic means
- IEC 60364-4-41 / IEC 61140
+ }9 |8 z% G; \6 V& O1 B5 a! }To be approved at the 49th CTL Plenary Meeting, in 2012
Question:
A client wants to combine a 230 V track system (according to IEC 60570) with a bus track system, which
! Q; I0 }: q- o# g, @9 Ptracks are accessible. Consequently the bus-tracks may be supplied by a SELV source only, or connected to
  v- ?4 a( U$ p2 Pcircuits, which are insulated from live parts by double or reinforced insulation. Due to the fact that both
DALI systems (or similar systems) and control systems of electronic ballasts do not comply with the
requirements of double insulation, our client created an additional safety circuit between the bus-track and
7 O. e' B9 K1 JDALI system/electronic ballast. The extra safety circuit consists of six zener diodes (>50 V) and four
/ v# D7 |5 `" e' t; pfuses (250 mA). The diodes guard the system to voltage higher than 50 V and the fuses protect the system
4 I5 V( r' D& ~' _, P" X* Tagainst high currents. In this way SELV conditions are guaranteed.
# J0 v0 p2 b8 k- qDecision:
6 A+ m& c7 N2 z9 Q" @In principle the SELV condition can be reached by electronic means at least according to the standards
3 G3 w% `, ?) S( Q" `; F4 m/ a. ?IEC 60364-4-41 and IEC 61140.

  T7 {, ^3 w1 Z, V/ ?2 u