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Hi All

Just wondering what needs to be done to use an AC 250A vintage welder with UK domestic AC socket.
The spec. says, that it needs to be plugged into 32 Amp AC 230V socket.
But UK domestic AC sockets are usually installed with 13 Amp trip switches.

Should we install 32 AMP trip switch to into our Mains AC Meter? Would it be a DIYer job? Or needs some
qualified electrical must do it?

Failing that, could we just use the welder with about half of its amp rating at say 100 Amp, without tripping the fuse in the house?

Thanks

Your PLUG will have a 13A fuse - the socket may (or may not) be on a 32A ring main but this isn't good enough.

No. You need a new cable running from a 32A breaker - the connection would be one of those 'blue' industrial sockets (can't recall the name).

If you used a 13A plug (socket) you'd blow the fuse every time you tried to use it - the surge current would be enough to do that. I've seen this happen on welders that are meant for use with a 16A circuit (running on a 13A plug) so a 32A welder has no chance at all.

Thank you for your info. I think we need qualified electrician to sort it out for us, or just pass this old vintage AC welder for sale locally in cheap price. I have no idea if the house is in 32A ring or not. I don't think it is. I recall even a Bosch Power Wash used to trip the fuse.

Will need to just go for a new inverter welder Made in China.

You need a dedicated circuit and the actual breaker type needs careful consideration as start up currents often trip MCBs

Best you get a local spark to spec and install

In general the voltage is 24 volt plus 1 volt for every 25 amp, so 250 amp would need around 34 volt so watts is volts times amps, = approx 8.5 kW at 230 volt that is 37 amp and that is without considering in rush or losses.

At that output I would have expected split or two phases to be used, can't use 3 phase with a AC machine, and yes a 32 amp supply with a 400 volt input would seem about right.

It depends how the output is controlled, with a moveable iron core as long as started fully out it would likely work, likely need a C or D type MCB not the normal B type.

There were a load of oil filled welding sets, these have two major problems, one the oil had PCB's (Polychlorinated biphenyls not Terry Pratchett particular crunchy bits) and the other was if dropped the uninsulated bars or wires inside could bend, and cause the in coming voltage to connect to out going earth clamp or stick. So they needed to be earthed, however the earth needed to be able to carry 200 odd amps, and it was common to find earth wires melted. Where I worked the welder was only used in one area and the earth wires in that area were at least 35 mm² where in a normal house the incoming earth is often only 16 mm².

Most firms got rid, and some times rather sneaky as they would give them away with of course paperwork to show no longer theirs, and the buyer now had the problem of getting rid of the PCB oil. We have known about the problem since late 70's, so finding oil filled welders today is rare, but I know the PCB oil has cost the heritage railway where I work a lot of money to dispose of equipment.

Today we tend to use DC welders, with AC 50% heat goes to stick and 50% to work, with DC the split is 25/75% which way depending if neg or pos earth, and TIG and MIG welders need DC, also they use a switch mode principle even when using AC, the supply is turned to DC then back to AC at a high frequency resulting in a smoother weld and also much reduced inrush and spikes on the supply.

Many DNO's require notification if doing any welding, as the spikes can cause electronic equipment to fail, fitting SPD may help, but in the main welding is not officially permitted on a domestic supply.

Clearly have to catch you first, and if using a inverter welder it is unlikely any one will complain. It is only the old welders that were a problem.

However to pay out for a 63 amp plug and socket and a 45 amp type D MCB, SPD etc etc and then be stopped is not funny, so before paying out I would check permitted. An inverter welder at 200 amp DC I have seen as cheap as £140, these will work on a 32 amp supply, and are unlikely to draw attention to them selves due to spikes on line or dipping of supply volts, once caught then too late.