DSH 568 Varistors (VDR’s) across the mains
http://decisions.iecee.org/icons/ecblank.gif DSH 568
Varistors (VDR’s) across the mains
19.11
60335-1(ed.4)
Question:
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.
Based on above concerns we ask for clarification:
1: 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.
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).
页:
[1]
