Earth leakage

[Electrix]

Hi All

I would just like some clarity on installing an earth leakage for welding plugs. Most manufacturers only make 2 pole and 4 pole earth leakages so how would a 3phase plus earth welding socket need to be connected as there is no neutral

[AndyD]

You can usually use a 4-pole earth leakage breaker on a 3 phase circuit that has no neutral. One issue may be that the test button is using the neutral to create the imbalance to trip when it's pressed in which case it's not a suitable.

Just as a side note, RCD's and welders are a notoriously problematic and can result in bad nuisance tripping due to the type of load a welder presents to the supply with harmonics , high inrush currents and spikes. What do the manufacturers instructions say about the supply requirements? Sometimes they recommend that no RCD is fitted. Can the circuit be installed without an RCD and still meet compliance requirements? If it can ie dedicated sockets etc I'd suggest a risk assessment and see if the RCD is necessary.