14.3 Tools shall be proof against humid conditions which may occur in normal use.
Compliance is checked by the following humidity test.
Cable entries, if any, are left open; if knock-outs are provided, one of them is opened.
Electrical components, covers, and other parts which can be removed without the aid of a tool are
removed and subjected, if necessary, to the humidity test with the main part.
The humidity treatment is carried out in a humidity cabinet containing air with a relative humidity of (93
±
2) %, obtained e.g. by placing in the humidity cabinet a saturated solution of Na
2
SO
4
or KNO
3
in water,
having a sufficiently large contact surface with the air. The temperature of the air, at all places where
samples can be located, is maintained within 1 K of any convenient value t between 20 °C and 30 °C. In
order to achieve the specified conditions within the cabinet, it is necessary to ensure constant circulation
of the air within and, in general, to use a cabinet which is thermally insulated.
Before being placed in the humidity cabinet, the sample is brought to a temperature between t and (t + 4)
°C. The tool is considered to be brought to the specified temperature by keeping it at this temperature for
at least 4 h before the humidity treatment.
The tool is kept in the cabinet for 48 h.
Immediately after this test, the tool shall withstand the tests of clause 13 at rated voltage or the mean of
the rated voltage range with the tool switch in the
″
on
″
position and under the following conditions:
For single-phase tools and for three-phase tools to be tested as single-phase tools: S1 of Figure 3 in the
″
off
″
position.
For three-phase tools not suitable for single-phase supply: a in Figure 4 in the
″
on
″
position, b and c in
″
off
″
position.
Then the tool shall withstand the test of clause 15 in the humidity cabinet, or in the room in which the tool
was brought to the prescribed temperature after reassembly of those parts which may have been
removed.
The leakage current limit values specified in the test of clause 13 are doubled if all controls have an
off-position in all poles.
They are also doubled if:
– the tool has no control other than a thermal cut-out; or
– all thermostats and energy regulators do not have an off position; or
– the tool has radio interference filters. In that case, the leakage current with the filter
disconnected shall not exceed the limits specified.
However, for class II tools, doubling of the value of 0,25 mA is only allowed if all controls have an
″
off
″
position.
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