Wiring Question.

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Hello,I read as much as I could on this question before I posted.  I think I am on the right track but am looking for confirmation.I have a 120v AC stick welder.  I have been practicing quite a bit.  I am ready for something bigger. I am on a tight budget, so I am looking for a used AC-225 or possibly an AC/DC-225 if I can find one in my price range.I had enough room in my breaker box, so I ran a dedicated 240v line to the garage.  I used #8 copper wire (3 conductor + ground) because I had some left over from a previous project.  I would have preferred to use #6 wire, but it costs a small fortune and I had the #8.  The length of wire installed is about 45 feet to receptacle. I had planned on using a 40-amp ciruit breaker.  From what I read this is what's recommended for #8 wire.  According to Lincoln, the AC-225 requires a 50-amp input.My question is, will I be ok if I increase the breaker to 50 amp?  Should I stick with a 40 amp breaker?  According to the info below, it would seem that I would be ok with a 50 amp breaker with #8 wire?  Is this safe?  I won't be running anything other than a welder off this circuit.Thank you very much. As per AC-225 manual:Using the following instructions, have a qualified electricianconnect this receptacle (NEMA 6-50R Type) to the powerlines at the fuse box. Three #10 or larger copper wires arerequired if conduit is used. For long cable runs over100'(31m), #8 or larger wire in conduit will be needed to preventexcessive voltage drops. Fuse the two hot lines with 50ampere super lag type fuses as shown in the following diagram.The center contact in the receptacle is for the groundingconnection. A green wire in the input cable connects thiscontact to the frame of the welder. This insures propergrounding of the welder frame when the welder plug is insertedinto the receptacle. If a separate disconnect switch isused, it should have two poles for the two hot lines and bothshould be fused for 50 amperes.Last edited by Grump99; 04-13-2011 at 08:07 PM.
Reply:Lots of guys run those stick machines off 30 amp dryer outlets. You are just limited on how much output you will get before the breaker trips. A 40 amp breaker would get you more output. I can't say as far as running a 50 amp breaker on 8ga wire. The codes do allow for running lighter wires for dedicated welder outlets, but I'm not up on the exact numbers..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I wouldn't do it. #8 wire should be protected at 40 amps. The sole purpose of the breaker is to protect the wire from overheating. I would run it with the 40 amp breaker, it should be fine except at the highest settings on the welder. If you absolutely need the 50 amp breaker you need to up the wire to #6. The NEC is in place for your protection.
Reply:Thanks for the help.  I will stick with the 40 amp.
Reply:Grump,You can run the 50amp CB on the #8 and you can even use #10 as the manual states up to 100'Greg,The NEC allows for using a smaller wire with a larger CB for dedicated circuits for Welders. Art 630Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:GUMP99    You are to be congradulated for having done your homework.  If your 8 guage circuit to your garage is a dedicated welder circuit you may certainly install a 50 amp breaker.  There is an exception to the code rules for ampacity and breaker sizes for dedicated welder circuits, because welder loads are not constant loads.  If the 8 guage were feeeding a steady constant load it would be rated at 40 amps to keep the wire from heating up.  Welding loads are not constant, every time you change to a new rod, stop and chip slag, or like me you unstick a stuck rob, the wire gets to cool off.Enjoy your new welder in good health.Last edited by nadogail; 04-14-2011 at 10:40 AM.Reason: I spell like I weld, not real goodI offer three choices: Good, Fast, & Cheap. You may pick two.Hobart AC/DC StikMate LXHarbor Freight AD HoodHarbor Freight Industrial Chop SawDeVilbis 20 Gallon, 5 HP Compressor
Reply:Thanks so much for the info everyone!  I will pick up a 50 amp breaker and start looking for a welder.Thanks again!
Reply:Ampacity on #8 THHN is 55 amps. 50 amp breaker should be fine. You generally need a GFI breaker for the garage, and the breaker needs to be approved for the brand and model panel you have.
Reply:55 amps on #8 is correct if the CB you are using is rated at 90 degrees C.  More than likely the CB is rated at 60 degrees C which puts the rating of the wire at 40 amps. (table 310-16) in the NEC.  According to section 630 in the NEC it allows you to derate the feeder size and the breaker based on the duty cycle of the welder being used.  The welder you purchase should have this info on the nameplate.  A GFCI is not required on a 240 volt circuit nor on a 120 volt dedicated circuit, so that should not be an issue.  If it were me I would install #6 THHN on a 50 amp breaker just so you have the overhead should you decide that you wanted to upgrade your welder in the future.  The difference in the cost of the wire will not be much and the 50A CB should cost the same as a 40.Last edited by Sparky0908; 04-15-2011 at 02:38 PM.
Reply:Just wanted to chime in with a quick update.I found a never-used Hobart Stick-Mate AC/DC for $250 on Craigslist.  Hooked it up and it works great with electrical service.Thanks again!
Reply:Interesting.  tag.Lincoln Power Mig 216Lincoln AC/DC-225/125Miller  625 X-Treme PlasmaMiller 211 Forney 95FI-A 301HF 91110Victor Journeyman O/PMilwaukee DaytonMakita  Baileigh NRA Life Member