AS 60974.11 pdf download – Arc welding equipment Part 11: Electrode holders
8.1 Protection against direct contact
An electrode holder without an electrode, fitted with a welding cable of minimum cross-sectional area as specified by the manufacturer, shall be protected against unintentionalcontact with live parts.
ln the case of type 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) a standard test finger according to lEC 60529 in the case of electrode holders of
1)type A, and
2)type B with the exception of the head;
a sphere in case of the head of type B electrode holders with
1) a metal sphere of 12;005mm diameter according to lEC 60529 for electrodes up to
6,3 mm diameter, or
a metal sphere of d;005 mm diameter for electrodes thicker than 6,3 mm diameterwhere the value of d is twice the maximum diameter of the electrode as specifiedby 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 metalparts of the electrode holder.
Conformity shall be checked by visual inspection.
The insulation resistance shall,after the humidity treatment, be not less than 1 MQ.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)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 d.c. voltage of 500 v betweenthe live parts and the metal foil， the ‘reading being made after stabilization of themeasurement.
The insulation shall withstand an a.c. test voltage of 1 000 v r.m.s. without flashover orbreakdown.Any discharges unaccompanied by a voltage drop are disregarded.
The a.c. test voltage shall be of an appropriate sine waveform 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 between the live parts and the metal foil.
9 Thermal rating
9.1 Temperature rise
The temperature rise caused by the rated current passing through the electrode holder, fitted with an untinned copper welding cable of 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 spot of the external surface of the handle.
Conformity shall be checked by the following test (see Figure 1).