IEC 60974-11-2021 pdf Arc welding equipment – Part 11: Electrode holders

8 Protection against electric shock Protection against direct contact 8.1 An ELECTRODE HOLDER without an electrode, fitted with a welding supply cable of minimum cross- sectional area as specified by the manufacturer, shall be protected against unintentional contact with live parts. In the case of CATEGORY A ELECTRODE HOLDERS , this requirement is also valid for the part of the electrode inserted into the ELECTRODE HOLDER . Electrodes having the minimum and maximum diameter as specified by the manufacturer shall be tested. Conformity shall be checked by: a) an access probe according to Table 6 of IEC 60529:1989 in the case of ELECTRODE HOLDERS of: 1) CATEGORY A , and 2) CATEGORY B with the exception of the HEAD ; b) a sphere in the case of the HEAD of CATEGORY B ELECTRODE HOLDERS with: 1) a metal sphere of 12,5 mm diameter according to IEC 60529 for electrodes up to 6,3 mm diameter, or 2) a metal sphere of d 0+0,05 mm diameter for electrodes thicker than 6,3 mm diameter where the value of d is twice the maximum diameter of the electrode as specified by the manufacturer. The sphere is to be applied to the opening with a force of 30 N ± 10 %. The springs not designed for carrying the welding current shall be insulated from other metal parts of the ELECTRODE HOLDER . Conformity shall be checked by visual inspection. 8.2 Insulation resistance The insulation resistance shall, after the humidity treatment, be not less than 1 M Ω. Conformity shall be checked by the following test : a) Humidity treatment A humidity cabinet is maintained at a temperature t between 20 °C and 30 °C to within ±1 K and a relative humidity between 91 % and 95 %. The ELECTRODE HOLDER without a cable fitted is brought to a temperature between t and (t + 4) °C and is then placed for 48 h in the humidity cabinet. b) Insulation resistance measurement Immediately after the humidity treatment, the ELECTRODE HOLDER is wiped clean and tightly wrapped in metal foil, covering the external surface of the insulation.