Adequate wiring for welders?

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I have three 240v welders, a Lincoln Invertec V250-s, Square Wave 175 TIG, and Power MIG 255.  I've been running them for the last few years on dedicated 40-50 amp circuits in my shop, using 8w3 and 6w3 wire.  The 255 calls for a 60a fuse, 80a on the Invertec, and 125a for the Square Wave.  Now, I have never tripped a breaker using any of the machines, but I will admit I am more of a hobbyist (and have never approached max output).I'm in the process of completing my latest shop build, which is separate of the current shop and will have its own power feed and panel box.  I'm wiring in four dedicated 240v plugs for my welders and plasma torch, three of which will be on the same wall as the panel box, and one on the other side of the shop.  Now, the three on the same wall are all within 20-24' of the panel box, and are being fed by 8w3 Romex cable with 40a breakers.  The 4th plug will be approximately 50' from the panel box, so I will be using 6w3 Romex on a 50a breaker.  My question is, does the wiring sound like it will be adequate for the machines I am using?  I recently learned that wire sizes for welding machines can be smaller due to duty cycles, but I am more concerned with tripping breakers in the panel box.
Reply:My suggestion is if you're starting from scratch give the welders what they want. You never know when you will need/want to crank the machine up for some reason. One thing with the bigger breakers is that once you get above 50 amps the plugs get really expensive so it is best to hard wire the machines. I did that with my Ideal Arc 250 with a 90 amp breaker. I never thought I would need to crank it up all they way until I learned about the joy of air arc gouging. Now I'm glad I did.My "collection":Homemade Stick WelderVictor O/A TorchAC 225Ideal Arc 250HF 90 Amp Flux CoreHF Mig 170Solar 2020 Plasma CutterPower i-Mig 140EHarris O/A torchHF Dual Mig 131140STAlpha Tig 200x
Reply:Are these the only welders you'll ever own? What is the route of the power supply after it leaves the utility transformer? The NEC chart addresses the risk of overheating the circuit. It does not address voltage loss. Each section of supply from the transformer will lose some voltage. Preserving voltage is important to welder performance. The formula is simple, it must be applied to each section of the supply, not the last branch circuit.Code limits breaker size to 15 amp for #14, 20 amp for #12, and 30 amp for #10. Beyond that, size your conductors for heat, or voltage loss, whichever is larger, then, if needed you can up the breaker rating up to 200% of rated primary amperage. This is seldom necessary.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:NEC allows you to de-rate the wire size based on the welder duty cycle. This can save you quite a bit in wire cost for low duty cycle machines. The breaker remains the recommended and the circuit must be labeled WELDER ONLY. See NEC 630 (Diagram 630.31(A) (2)). On your Square Wave because it's a 100% duty cycle you likely can't de-rate. I normally wire my welder drops according to the manual which takes into account loss and de-rating allowances. Generally you don't need to adjust for wire loss until you exceed 100'. Generally anything over 50 amps is hard wired with a disconnect. In some cases you can forgo the disconnect if the panel is within sight.De-rating has been discussed in the past:http://weldingweb.com/vbb/showthread.php...t-has-20a-plugNow you can likely get away with the method you've been using. It's not code, and it's not ideal. I use my Sycrowave at the farm sometimes on their 50A circuit... works fine until I near the duty cycle... then I'm tripping it all the time.
Reply:Thanks for the information.  I doubt I will be changing welders anytime soon, as they cover just about every welding need I have.  The only potential change I can see is possibly upgrading to a larger A/C TIG machine, but seeing how I do very little aluminum welding, I think I am OK right now.  Hard wiring the machines really isn't an option, as I have two different shops I will be using the welders in.  The two shops are less than 100' between one another, but are on different panels and each has its own feeder power wire from the meter.  Even with 8w3 and 6w3, I am covered for all the machines, but I may have to change breakers.  Of course, that would only be necessary if I actually start tripping the 40 & 50a breakers in the panel now.  Regardless, I am going to label each outlet with wire and breaker size.
Reply:125 amp input for a 175?
Reply:Originally Posted by Sharon Needles125 amp input for a 175?
Reply:Something is wrong with those numbers for the Lincoln. I run my syncrowave 250 on a 100 amp breaker and 6 gauge wire.Miller Multimatic 255
Reply:I use a single "extension cord" between all my machines. I like the setup quite allot really.  I can use any of my machines anywhere in the shop or out the door. None of them are stuck in their spot because "that is where the plug is".I have a very very short run (2 feet) of hard wire from the box to the plug from where the 25' extension cord gets plugged in. I forget what the cord is size wise right now. It runs both my 250MM and 250SW as well as my plasma cutter, oven, anything 220v.12v battery, jumper cables, and a 6013.I only have a facebook page. https://www.facebook.com/pages/VPT/244788508917829
Reply:Yeah those numbers appear to be based on the 200% rule. I normally setup my transformer machines based on 125% just like a motor or resistance load. NEC requires 125% but no more than 200% on these type of loads. Using 125% would put you at an 81.25 amps (65*1.25=81.25) so round up to 85 or 90, or fudge and call it 80.  For comparison, my Syncrowave manual suggests 150% on normal acting fuses/breaker. A lot of guys use the nameplate amperage and while it doesn't meet code they never have any issues because they aren't pushing the duty cycle and they aren't inspected connections because they are using a plug/outlet. Technically code ends at the plug... so do what you want... but if you use a hard wired disconnect you cannot fudge the hookup because it now extends to the machine. This is a snippet from the manual posted above for reference.
Reply:Originally Posted by Louie1961Something is wrong with those numbers for the Lincoln. I run my syncrowave 250 on a 100 amp breaker and 6 gauge wire.
Reply:The thing to ask yourself is, whats going to be more cost effective in the long run. Getting the appropriate power installed once, or having to buy machines over the long term to suit your power restrictions. It depends on your needs, I know down here in New Zealand if you can make sure you have enough power at the wall then the door opens for all kinds of incredible machines on the used market. Where as to buy machines that are rated for conservative power supplies tends to be quite expensive as the used market down here is mostly industrial stuff and to buy lower volt single phase gear that has high output you basically have to buy brand new as they have not flowed onto the used market yet.Gear: Esab power compact 205 with tbi industries torch         BOC Smootharc 185dc tig         Miller Syncrowave 350LX
Reply:The thing to ask yourself is, whats going to be more cost effective in the long run. Getting the appropriate power installed once, or having to buy machines over the long term to suit your power restrictions
Reply:Originally Posted by Jason280I'll have enough power, and the wiring will be correct...the only issue I may encounter is simply undersized breakers in the panel box.  Of course, that's an easy fix.  Either way, I'm going to have all the plugs clearly labeled to prevent any potential problems down the road.
Reply:Originally Posted by Broccoli1Those Lincoln 175 are power hogs
Reply:Originally Posted by Jason280That's what the manual calls for, at least for A/C TIG welding at 150 amps....http://www.lincolnelectric.com/asset...oln3/im687.pdf
Reply:Thanks for all the information.I finished pulling all my wire today, only thing left to do is get it hooked up in the panel box (and get power to the panel).  I ran a metric ***-load of plugs, wire, and boxes for lights/ceiling fans, so it will be fun getting it all situated at the box.  I ended up with 4x 240v plugs for the welders (all 40-50a), 3x 30a 240v plugs for my lift and compressor (with 1x "extra"), and 35-40x 120v plugs.  3x of the 120v plugs were run with 10/2, which may be overkill, but I had some extra wire.  All the other 120's are on 12/2, so I should be good for 20a on all the plugs.  I was a little conservative on running the plugs, and no more than 4-5 are on one breaker.  I actually got a little nervous that I would run out of breaker space!
Reply:Jason, sounds like you did what I did on my garage addition. Three 20 Amp circuits in three rooms above.  Two 20A circuits with multiple outlets in the two car car garage below, plus several 15 Amp circuits for lighting, garage door openers and a beer fridge.  Then there's the 30 and 50 amp circuits for welders.  Never ran the final 70 A circuit for the Synchrowave buts it's hanging off the panel. I can't count the number of duplex outlets I installed, but maybe 25-30, so double that. I just about wore out a ladder pulling wire. Then there were the outside security and door lights.  Fun stuff.Edit:  I mostly used Pass & Seymore outlets from an electrical distributor.  Sub panel was Cutler-Hammer with CH breakers.Last edited by Oldendum; 09-21-2015 at 10:15 PM."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:I just about wore out a ladder pulling wire.