The no load voltage at the origin of the circuit is 242V and the no load voltage at the outlet where the welder is connected is 241V. With a total circuit load of 32 amps (26A for the welder plus another couple of small appliances at 6A) the voltage under load at the origin of the circuit is 237V and at the outlet where the welder is connected the under load voltage is 208V.
As you said that the voltage at the circuit’s origin with ” 32A ” is ” 237V ” ( the circuit origin is the place where the cable 2.5mm² is connected ), and at the connection points of the welder is ” 208V “, that means the voltage drop is caused by this cable, so :
– The distance is ” 50m “.
– The total load current is ” 32A ” where the welder current is ” 26A “.
As the welder current contains a lot of Harmonics that can’t be measured by the standard equipment, the real welder’s current is bigger than ” 26A “. For this case it’s better to use a cable’s section around ” 6mm² ” where the method of installation of this cable should be taken into consideration.