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

IEC 60974-11 pdf – Arc welding equipment – Part 11: Electrode holders
8Protection against electric shock
8.1 Protection against direct contact
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 contactwith live parts.
ln the case of cATEGORY A ELECTRODE HOLDERs , this requirement is also valid for the part of theelectrode inserted into the ELECTRODE HOLDER . Electrodes having the minimum and maximumdiameter as specified by the manufacturer shall be tested.
Conformity shall be checked by:
a) an access probe according to Table 6 of lEC 60529:1989 in the case of
ELECTRODE HOLDERS
of:
1)cATEGORY A, and
2CATEGORY B with the exception of the HEAD;
b) a sphere in the case of the HEAD of cATEGORY BELECTRODE 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 don0,05 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 themanufacturer.
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 metalparts of the ELECTRODE HOLDER –
Conformity shall be checked by visual inspection.
8.2Insulation resistance
The insulation resistance shall, after the humidity treatment, be not less than 1 M
Q.
Conformity shaM be checkedby the following test :
a) Humidity treatment
A humidity cabinet is maintained at a temperature t between 20 °C and 30 “℃ to within ±1 K anda relative humidity between 91 %and 95%.
The ELECTRODE HOLDER without a cable fitted is brought to a temperature between : and(t+4) “C and is then placed for 48 h in the humidity cabinet.
b)lnsulation resistance measurement
lmmediately after the humidity treatment,the ELECTRODE HOLDER is wiped clean and tightlywrapped in metal foil, covering the external surface of the insulation.
The insulation resistance is measured by application of a DC voltage of 500 v between the liveparts and the metal foil, the reading being made after stabilization of the measurement.
8.3Dielectric strength
The insulation shall withstand an AC test voltage of 1000 V r.m.s. without flashover orbreakdown.Any discharges unaccompanied by a voltage drop are disregarded.
Conformity shall be checkedby the following test :
A dry and clean ELECTRODE HOLDER is tightly wrapped in metal foil, covering the external surfaceof the insulation.
The AC test voltage shall be of an appropriate sine wave-form with a peak value not exceeding
1,45 times the r.m.s. value,having a frequency of 50 Hz or 60 Hz, applied for 1 min betweenthe live parts and the metal foil.
Alternative test: A DC test voltage of 1,4 times the r.m.s. test voltage may be used.
Thermal rating
9.1Temperature rise
The temperature rise caused by the RATED CURRENT passing through the ELECTRODE HOLDER,fitted with an untinned copper welding cable or maximum cross-sectional area and a rod with
the maximum electrode diameter as given in Table 1, shall not exceed 40 K at the hottest spotof the external surface of the HANDLE .
Conformity shall be checkedby the following test (see Figure 1).