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http://bbs.angui.org/thread-104454-1-1.html
/ j0 C5 ^0 _8 G4 D! J' gVaristors (VDR’s) across the mains2 i1 i2 z0 p) x5 J/ |2 K: @: l* H
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Question:9 q) S& L$ x2 B1 t! F- g
Reports from different Testing Laboratories and clients expose essential differences in interpretation and testing practice between laboratories and/or Certification Bodies.
( g. Z4 }& I( k) ]/ i0 a: z& J9 C, j7 ?6 TActually, the practice of one Certification Body is now being a market factor.% l) B2 B8 \+ t
Based on above concerns we ask for clarification:8 T$ \6 V- x* M' ], K& v
1: Shall Cl. 19.11 be strictly followed or can solutions given under 2. be accepted./ ?" V6 m1 }) E; c' x# i2 A
2: Can any of the decisions (made by OSM/EE) be accepted?0 k0 B& `! {( p! R
- A: VDR’s across the mains are accepted if the VDR is separately certified according to IEC 61051-1 or according to CECC 42200.
7 J9 i8 `& r$ W, Y8 W$ J2 t" K- B: VDR across the mains with a protective device to guard against short-circuit is acceptable.
$ A8 C5 B, M* d/ M M/ d- C: If A and B are acceptable, should, because of the fact that VDR’s may burn or burst during life-time due to an increasing temperature stress caused by increase of leakage current with a number of switching cycles in the VDR, a thermal interrupting device on the VDR connected in series with the VDR be required." |6 _4 m( \/ X0 Y! r) m0 |- ~; H
Decision:; x& v4 h5 p; E' d8 n5 \' r
1. VDR’s are not short-circuited if they are used within their manufacturer’s declared specification, when tested according to Sub-clause 19.11.2 of IEC60335-1(1991)./ K4 w, S: z+ H u# w. o3 ?/ m
2. VDR’s are short-circuited regardless of compliance with IEC61051-1, when tested according to Subclause 19.11.2 of IEC60335-1(2001).) W: i/ b" o4 ^2 O1 X& d
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