BS EN IEC 60974-2:2019 pdf free download – Arc welding equipment
6.5 Leakage current between welding circuit and protective earth
With the cooling system filled with the cooling liquid specified by the manufacturer (see 1 2.1 e)), the leakage current from the torch to the protective earth connection of the cooling system shall not exceed 1 0 mA DC. Conformity shall be checked by applying a DC voltage of 500 V at room temperature between the protective earth connection and a copper pipe to simulate the torch connected to the outlet of the cooling system by a hose with a maximum length of 0,5 m as shown in Figure 1 . The minimum inner diameter of the hose shall be 5 mm. The minimum length of the copper pipe shall be 10 cm with a minimum internal diameter of 5 mm. The cooling system and the simulated torch are filled with liquid for the test. The pump is operating.
7.2 Cooling liquid overflow
When filling the cooling system in accordance with the manufacturer’s instructions, overflow or spillage shall not result in electric shock. Conformity shall be checked by the following treatment and test. The liquid container is completely filled. A further quantity of liquid equal to 15 % of the capacity of the container or 0,25 l, whichever is the greater, is then poured in steadily over a period not to exceed 60 s. Immediately after this treatment, the equipment shall pass the dielectric strength test of 6.1.5 between input circuits and exposed conductive parts.
7.3 Hose coupling devices and hose connections
If hose coupling devices or hose connections, which often have to be undone, are placed above or near to live parts, these live parts shall be protected from cooling liquid by splash proof enclosures, with drains or other appropriate measures. An exception is made for live parts of the welding circuit.
9.1 General requirements
A cooling system shall not break down and increase the risk of electric shock or fire under the conditions of operation of 9.2. These tests are conducted without regard to temperature attained on any part, or the continued proper functioning of the cooling system. The only criterion is that the cooling system does not become unsafe. These tests may be conducted on any cooling system that functions correctly. The cooling system, protected internally by, for example, a circuit-breaker or thermal protection, meets this requirement if the protection device operates before an unsafe condition occurs.
Conformity shall be checked by the following tests.
a) A layer of dry absorbent surgical type cotton is placed under the cooling system,extending beyond each side for a distance of 1 50 mm.
b) Starting from the cold state, the cooling system is operated in accordance with 9.2.
c) During the test, the cooling system shall not emit flames, molten metal or other materials that ignite the cotton indicator.
d) Following the test and within 5 min, the cooling system shall be capable of withstanding a dielectric test in accordance with 6.1 .5 b) of IEC 60974-1 :2017.