I think you need to share more info Stewart...
I'm not an electrician.
I do have a MIG welder with max output at 135 amps which works very happily from my domestic supply with a 13 a fused plug. It's good for steel up to 5mm thick max (although I've not welded 5mm thickness so far usually around 4mm max)

Output current on a welder is NOT equal to the input current.
A simple transformer-style welding unit converts the input voltage and current electricity into a high current and low voltage supply.

Just in simple terms remember that Power(Watts) = Current(Amps) x Voltage(Volts).

It's important to check the output ratings for different duty cycles and rest times. Just as example 60% means welding time is 6 minutes and rest time is 4 minutes.

Do you have a MIG welder or Stick (Arc) welder?
MIG welders don't generally draw as much power as most Arcs welders.

Here in UK that 135 amps is just about on the limit for plugging into domestic supply.

Just trying to help......