Voltage drop

Feb 06, 2013 2 Replies

Currently have my welder (Shopmaster 300) behind the house and keep it covered with a tarp when not in use. Not ideal - but was OK back during the summer when it was hot and seldom rained. Not worth a durn now... Want 'real' electricity in my workshop, however the local power co wants *two grand* to hook it up because it is not a dwelling. Would only be $200 if it was a house as no line extensions are involved. Intermediary pole on the line to our house is literally 30 feet from the corner of my shop.



Can get enough #2 aluminum URD for about $400 (if the county will let me switch gears since I already permitted this.) Have checked my welder with a clamp on amp meter and welding what I currently need to weld again was pulling 38 amps. #2 aluminum is rated 75 amps and according to an on-line calculator at 240 volts, 350 feet and 40 amps the voltage drop would be 8.2 volts or 3.43%.



Does this sound reasonable for an old transformer style machine?


I am not familiar with the Shopmaster 300, but 38A sounds low for what sounds like a 250 - 300A transformer welder. I had a Miller Dialarc

250HF that was rated at about 75A max at 240V in. Your mileage may vary.

BobH

Multi-process machine, Ernie says it is a dinosaur:-( 38 amps was with aluminum MIG and .035 wire. I'm sure it would pull more if I set it up for .047 wire. And likely a bunch more in TIG, at least the old 330 A/BP I had back in the early 80s would...

More concerned with the voltage drop of what I currently need to do, not what the future holds. Little bit of Googling I did suggests that inverter based welders are much more sensitive to voltage drop than transformer ones. As long as the cooling fan still runs!

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