Different parts of an appliance that can move relative to each other in normal use or during user maintenance shall not cause undue stress to electrical connections and internal conductors, including those providing earthing continuity. Flexible metallic tubes shall not cause damage to the insulation of the conductors contained within them. Open-coil springs shall not be used to protect the wiring. If a coiled spring, the turns of which touch one another,is used for this purpose, there shall be an adequate insulating lining in addition to the insulation of the conductors.NOTE 1 The sheath of a flexible cord complying with IEC 60227 or IEC 60245 is regarded as an adequate insulating lining.Compliance is checked by inspection and by the following test.If flexing occurs in normal use, the appliance is placed in the normal position of use and is supplied at rated voltage and operated under normal operation.The movable part is moved backwards and forwards, so that the conductor is flexed through the largest angle allowed by the construction, the rate of flexing being 30 per minute. The number of flexings is− 10 000, for conductors flexed during normal use;− 100, for conductors flexed during user maintenance.NOTE 2 A flexing is one movement, either backwards or forwards.The appliance shall not be damaged to the extent that compliance with this standard is impaired and it shall be fit for further use. In particular, the wiring and its connections shall withstand the electric strength test of 16.3, the test voltage being reduced to 1 000 V and applied between live parts and accessible metal parts only. In addition, not more than 10 % of the strands of any conductor of the internal wiring between the main part of the applianceand the movable part shall be broken. However, if the wiring supplies circuits that consume no more than 15 W, then no more than 30 % of the strands shall be broken.