Originally Posted by 12husky
I have a Lincoln Square Wave 355 TIG I am wiring into my new shop. When I had it in my garage it was on a 50 amp breaker, but will be putting it on a 125 amp breaker now. I would like to be able to roll it around the shop so am looking to put about 50' of cord onto it hardwired into my breaker box.
How do you guys recommend setting it up?
Flex conduit with THNN
This is something you need to be careful with, because your options are somewhat limited to be compliant with electrical code. If you are subject to inspection, you need to do things strictly to code, and even if you're not going to be inspected, following code is a good idea because it was written primarily for safety reasons.
I have a slightly smaller machine (Precision TIG 275). Lincoln specifically calls out in the manual a 100 amp breaker and #4 copper wire. The trouble comes in if you want the machine to be moveable, there are only a couple ways to do this and be code legal.
1. Use flexible conduit and make a continuous run of wire through it back to the breaker.
2. Use the correct size of SOOW cord, with a plug/receptacle that is appropriate for the current that will be carried by the cord.
I wound up doing #1 because of cost. I have my machine located close to a box on the wall where the flexible conduit is anchored. I have some excess to allow the machine to pull away from the wall for cleaning and changing cylinders, but nowhere close to 50 feet. I bought "extra flexible" 1" liquid tight conduit from McMaster-Carr with the correct connectors, and it's not all that flexible with three #4 conductors in it. I can't imagine 50' of this in a coil, especially when you take into account that the ends have to be fixed...you can't unplug it to roll it up.
Per code, if you go the cord route, it has to have a plug/receptacle to allow it to be unplugged. The other thing with cord is you might have to go larger than what's specified in the manual because wires in cord have smaller allowable ampacity than wire in conduit because they're tightly bunched together and get hotter. The plug/receptacle is where things get stupid expensive once you go above 50 amps. I checked, and I was going to have several hundred dollars wrapped up in the plug/receptacle rated for 100 amps to match the breaker, not to mention what I would have in the cord.
Here's an example of a 100 amp plug/receptacle combo:
Good luck! Every once in a while I look on Ebay for a plug/receptacle combo, but I haven't stumbled onto one yet. I would like to have my welder on a cord for convenience, but I haven't come up with the hardware to do it right yet.