In clause 13.2, it is specified that 2N for internal parts and 30N for the outside are applied simultaneously while taking measurement of clearance. However, it is not specified that forces are applied to internal parts while taking measurements between two internal parts, ex. primary circuit component and secondary circuit component.
Which is the appropriate method to measure clearance between two internal parts ?
a) 2N forces are applied to the both parts simultaneously.
b) First, a 2N force is applied to one part and removed. And then a 2N is applied to the other one.
c) Other opinion
The standard does not specify a transformer overload test, as there is, , for example, in IEC 60950.
If it is obvious, based on engineering judgment of the technical design of the product, that due to a single fault condition (e.g. component failures, short circuit of functional insulation) an overload situation on a transformer is likely to occur, which approach should be followed?
1) The actual overload on the transformer shall be performed, taking into account the 'characteristics' of eventual protective devices.
2) All possible single fault conditions shall be performed. For those situations where the protective device reacts, the current through the protector shall be measured and the characteristic of the protector shall be taken into account.
3) No overload condition shall be created, since the standard does not specify this in wording.
4) Other possibilities.
Various IEC standards require that specific tests be performed in a humidity chamber. The specification of the relative humidity is in several formats. How should the tolerance on the relative humidity specification be interpreted?
(1) Unless clearly noted otherwise, the tolerance specified for humidity is considered to be in percent relative humidity, % RH.
(2) It is intended that the set point of the humidity chamber controller be set within the specified range and that the humidity remains within the specified range.
(3) Confirmation that humidity is within the specified range shall be made by a humidity measuring instrument according to CTL DSH 251A.
（3）湿度在规定范围内，由湿度测量仪根据CTL DSH 251A进行确认。