Welder Circuit

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Hi all;I just purchased my first mig welder, a Lincon Weld Pak 175HD. The operating manual states that the wedler requires a #8 conductor circuit protected by a 40amp breaker. It further states that the circuit must be comprised of 2 hot's and a ground (neutral not needed). The question is, can the ground be connected to the neutral bus? The breaker panel does not have a ground bus in it.
Reply:Hey Softail,Yes, your ground can be connected to the neutral bus, as most panels have the neutral/ground interconnected. My panel has a #10 copper ground to the waterpipe and is tied in to the neutral bus inside the panel. It should work fine....DennyComplete Welding/Machine/Fab. ShopMobile UnitFinally retired*Moderator*"A man's word is his honor...without honor there is nothing.""Words are like bullets.... Once they leave your muzzle, you cannot get them back."
Reply:If you don't have a ground you should do what yorkie did, and make an improvised ground and splice it into the neutral bus in the main panel.
Reply:Yorkie, 65535 - Thanks for the advice, I will check to ensure a ground exists for this panel. Just a few questions concerning theory, in a 110 volt circuit power is supplied via the black wire, when a load is plugged in and turned on that power drives the load and continues through to the neutral and out to the local street grid. Is this accurate? If it is, isn't there voltage potential on the neutral? would this condition (having voltage at the ground stab of the welder plug) be undesirable for the welder?
Reply:I don't think Yorkie was saying the he did an improvised ground, I think he was just describing how the neutral is bonded to an earth ground in his panel, as it is in all main service entrance panels.The ground you need to connect your welder circuit to is the buss in the panel, not to an earth ground or bonding "splice."  In the main panel, the neutral buss and ground buss are bonded together and indeed might just be a common buss.  They will be separate busses in subpanels within the same building.Also, FYI, Lincoln is EXTREMELY conservative with their electrical "requirements," far more stringent than the National Electric Code, just to cover their butts.  They aren't the ones shelling out the money for the copper and splicing it in the boxes.Feel free to use #10 wire for that machine, and even #12 if you would like to take advantage of the provisions that the NEC makes specifically for welding machines that have a low duty cycle like yours.In the US, the 120V potential is supplied by the hot (usually black) wire, yes, and the neutral should be at ground potential, though it carries current in normal circumstances, and the ground does not carry current in normal circumstances, which is why they should not be bonded together anywhere except the main service entrance.
Reply:One of my machines is a small 140 amp unit that's 50' from the panel and #12 didn't work well. I had to increase to #10.You always have the option of using aluminum #8 or #6. It will be cheaper than smaller copper and handle almost every bit of the current of equal sized copper. Just make sure to use "no-ox" compound on all connections. Don't let anyone tell you that aluminum is not safe. It is. There were problems with it many years ago due to the plain lack of knowledge of its use. It will work just fine and it's probably what the power company even feeds your house with.
Reply:Aluminum is certainly safe when terminated properly.  Using NoAlOx, like you say, well as making sure the actual devices are designed for aluminum, marked Cu7Al, or Cu9Al, usually.As a general rule on these wire sizes, you go one size larger for aluminum.  Instead of #12 copper, use #10 aluminum, etc.How in the world was 50' of #12 insufficient for a 120V welder on a dedicated circuit?  That should handle a 100% duty cycle application.  Were you just tripping the breaker?
Reply:too much voltage drop. The arc was unstable and inconsistant. This was determined simply by plugging a shop light into that receptacle and seeing how much it dimmed when welding. I then used the DVOM and saw approx an 8-10V drop (on low peak) when the machine was run to the limit. Switching to #10 solved all problems.
Reply:Yeah, classic signs of voltage drop, and proper solution, too, but an odd situation that I wouldn't have expected in my experience or in the numbers.  Glad you got it taken care of!
Reply:I've always been a firm believer in using one size larger (sometimes, 2) on all of our vehicles that we produce and we have a zero failure rate by doing so.Of course, when its our own, we always try to be a little cheaper and this is what happens! Voltage drop is something that many overlook and don't understand, but it really is simple to figure out. It's the cause of many problems on our "competitor's" products.