DSH 568 Varistors (VDR’s) across the mains

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广东安规检测
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DSH 568 5 C$ ?8 P5 e" Q- v. f4 x/ ?2 c

Varistors (VDR’s) across the mains . R# c0 q2 I* g. F$ Y  J( R

19.11

60335-1(ed.4) 6 e+ g# j* i: n; h2 R

2 ?4 x' Y7 U/ m3 v( D1 F) ?% @Question:
0 `! u" |. Q% [Reports from different Testing Laboratories and clients expose essential differences in interpretation and testing practice between laboratories and/or Certification Bodies.
Actually, the practice of one Certification Body is now being a market factor.
3 n9 X) g$ i) t0 UBased on above concerns we ask for clarification:
8 G  H% C' C2 |  z' c# p2 Y1: Shall Cl. 19.11 be strictly followed or can solutions given under 2. be accepted.
2: Can any of the decisions (made by OSM/EE) be accepted?
- A: VDR’s across the mains are accepted if the VDR is separately certified according to IEC 61051-1 or according to CECC 42200.
- B: VDR across the mains with a protective device to guard against short-circuit is acceptable.
- 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.
& b# Q  k8 Z  X* @Decision:
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).
2. VDR’s are short-circuited regardless of compliance with IEC61051-1, when tested according to Subclause 19.11.2 of IEC60335-1(2001).


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