A question about clause 21.1 and detachable parts
21.1 Appliances shall have adequate mechanical strength and be constructed to withstand such rough handling that may be expected in normal use.
Compliance is checked by applying blows to the appliance in accordance with test Ehb of
IEC 60068-2-75, the spring hammer test.
The appliance is rigidly supported and three blows, having an impact energy of 0,5 J, are applied to every point of the enclosure that is likely to be weak.
After the test, the appliance shall show no damage that could impair compliance with this standard and compliance with 8.1, 15.1 and Clause 29 shall not be impaired. In case of doubt, supplementary insulation and reinforced insulation are subjected to the electric strength test of 16.3.
As shown in the figure, the pressure cooker uses a flexible PVC film as the operating panel, on which the function indication marks of each switch button are silk-screened. It is fixed to the appliance housing behind it by glue. The PVC was removed when subjected to clause 22.11. Obviously, the operating panel made of this PVC film is a detachable part.
When the PVC is in place, the impact test of clause 21.1 is pass, and the test cannot damage the flexible PVC film and the plastic housing behind it. If the PVC film is removed, the impact test is directly applied to the plastic housing behind the PVC film, the plastic housing breaks, and the test finger can touch the live parts inside.
Do we need to remove the PVC before testing in clause 21.1?
In my opinion, we don’t need to remove the PVC film. Because clause 21.1 does not require removal, and clause 21.1 requires testing under “normal use” conditions. If the PVC film is removed, it is obviously not in normal use.
Then the question is, should the detachable parts be removed before testing in clause 21.1? The standard does not say, so I think we should base it on the characteristics of the product. In the example above, it does not need to be removed. If it is an air purifier as shown in the figure below, after its user-replaceable filter is removed, the internal fan blade guard needs to be tested in clause 21.1, because I think the state of removing the guard is normal and is also a common normal usage state.
