Tripping RCD when using welding equipment.

[BigJonesy]

Hi all, this is an odd one but I just want to check out that my suspicions are correct. I've been asked to look at the electrics at a garage unit, but the only thing that is tripping the RCD is this particular industrial welding equipment. To my mind, this suggests that the equipment is faulty and probably needs PAT testing. Would you think the same thing? I could obviously get there and do a ramp test etc. but I think that would be a waste of time as the only time it trips is with this particular equipment. It's 3 phase, using B type MCBs too. They don't trip, just the RCD. Otherwise I'd have said change the breakers to C type. I could be wrong of course and would appreciate your opinions. Thanks.

 

[bignod]

On site with me all weldind sets are pluged into dedicated welding sockets and they are all rcd protected with pilot earth protection as well so to protect the cable going to the sets,the sockets are normally either 80 or 100A rated