Powermig 350mp

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Hello, allI recently bought a Lincoln POWERMIG 300MP, set up for SINGLE PHASE 60 HZ  230V.Reading the instructions in the manual under installation, its say RECOMMENDED INPUT WIRE AND FUSES-SINGLE PHASEIt say to use #6 AWG wire, I have done that.Under Wire or Breaker Size, it say to use 80A Breaker, So I have put in a 80A Breaker in the 200A main panel. I am using a 50A 250V Receptacle to plug the welder in. Lincoln says to fuse the two hot lines with super lag type fuses. The super lag type fuses will be in the 100A Safety Switch Disconnect  Box that sits empty right now. The question is what size should the super lag fuses be? 80 AMP? 50 AMP? I really don't want to burn the house down. Thanks,
Reply:At least 80A fuses to match the breaker.  You are getting by with #6 wire and a 50A receptacle because of the non-100% duty cycle of the machine at its higher outputs.  Since the breaker is protecting the wire from short-circuits and overloads, you can (and I would) use 100A fuses in the disconnect.  It's just for insurance, really, and 100A protection is plenty close enough for auxiliary short-circuit protection.  This makes sense to me as an electrician.  Specific rules of your authority having jurisdiction may vary.Nice machine, enjoy!Last edited by MAC702; 07-28-2006 at 04:27 AM.
Reply:Mac,I just picked up a PM215, and I am wiring up the circuit in the garage now. Reading the owners manual, it tells me to use #10 AWG on a 60 amp breaker for a run of less than 100' (which mine is). It also mentions these superlag fuses. What is the point of these fuses, and what size do I need to install?Thanks,Mike
Reply:100A super lag fuses? Dosen't the super lag fuses have to be the same amperage or lower than the80A Breaker in the main 200A panel for protection? How can it be a higher than 80A, down the line with 100A super lag fuses in the safety disconect switch. Wouldn't the 80A Breaker now be over protectected and not trip OFF?I'm not electrician so I want to make sure. Thanks
Reply:Originally Posted by candyapple_redDon't the super lag fuses have to be the same amperage or lower than the80A Breaker in the main 200A panel for protection? How can it be a higher than 80A, down the line with 100A super lag fuses in the safety disconect switch. Wouldn't the 80A Breaker now be over protected and not trip OFF?
Reply:Originally Posted by WannabeMac,I just picked up a PM215, and I am wiring up the circuit in the garage now. Reading the owners manual, it tells me to use #10 AWG on a 60 amp breaker for a run of less than 100' (which mine is). It also mentions these superlag fuses. What is the point of these fuses, and what size do I need to install?Thanks,Mike
Reply:Hmmm, thanks for your help. Thinking back,I had an electrician wire my DeVilbiss 5hp compressor in the late 80's and at the 200A main panel he put 40A Breaker and at the Safety Disconnect Box he put in 60A Super Lag fuses. He did what you have suggested having the super lag fuses in the Safety Disconnect Box at a higher AMP than the breaker.When I bought the Safety Disconnect Box for my welder at the Electrical Wholesaler he sold me two 80A superlag for box. Looks like he wants me to come back to by more fuses. I will go with two 100A Super Lag fuses as: Two Electricians are better than one Electrical Sales Man.Thanks, again to MAC702 Ok, now I feel comfortable about pluging her in and firing up BIG RED!  Great FourmLast edited by candyapple_red; 07-28-2006 at 01:37 PM.
Reply:Not to confuse the issue here but I have a different point of view.First if you have a 50 amp receptical wire it up for that.    That would be atleast #6 wire depending on the distance covered.     Then install the proper branch circuit protection for that wire and outlet.    Follow the NEC guidlines.Sure exceptions can be made for welders that is codified in the guidlines but the problem as i see it is the temptation to use that outlet for other devices that may presnt a different load to the branch circuit.    Plasma cutters and battery chargers come to mind right away.As t the Fusing I think Lincoln is being smart with their reccomendations.     Breakers aren't always that reliable and the curves defining how the devices trip can vary widlely from breaker to fuse.     Besides that I've seem some nasty things happen when only breakers are used in industrial settings.One of these interesting things was the failure of a 30 Horsepower compressor.     Apparently the pump rotor locked up and stalled the motor.     Niether the motor stater nore the breaker in the local panel box reacted fast enough.     The rotor in the motor literally melted (aluminum) further locking the machine up, the motor starter in a very literal sense blew up (or of the compressors panel), the wireing from the local sub panel to the compressor melted down and finally a 500 amp breaker in the main panel tripped.     This all happend real fast and fortunately the wiring was contained in conduit and the room was concrete.    The wiring feeding the compressor panel was rated for the 100 amp branch circuit breaker but that didn't keep if from burning up when the breaker failed to trip.The point of this editorial is that if circuit protection fails to work your short circuit currents are huge.    Failure of a overload device can lead to melted wire, flying particles of former electrical components and a general mess.   A few caveats here.    The short circuit potential in a home service is dramtiacally different than in a large 460 plant service.     If you have an industrial service it pays to contact the local utility and ask about short cricuit currents and devices with the proper ratings.     The wrong breaker or fuse may do nothing at all to open large short circuit currents.IU geuss breaker sizing is a pet peave of mind after working on problems like described above and others where more attention should have been paid to the overload protection and correct installation of the branch circuit.   In other words loo for the safe solution.Dave
Reply:Hmmm, food for thought:confusedYears ago, when had my Devilbiss 5hp compressor wired in at the 200A panel it had 40A 2-Pole Breaker in the main panel with the Super Lag 60A fuses in the Safety Disconnect Box.It only blew the Super Lag 60A fuses once, and 40A Breaker never fliped off.Shouldn't the 40A Breaker have fliped off first? Strange, unless the Super Lag 60A are more sensitive even with the higher rating, is my guess.
Reply:I bet the MAC  can set us STRAIGHT. I was TOLD that a reg. breaker will go 65%  higher than rated,before tripping . IF that's true, a 40 amp breaker might NOT trip untill  about 66 amps.[SIZE="5"Yardbird"
Reply:There are a lot of factors to take in, not counting the tolerances to which the devices are made.Time-delay circuit breakers (like most) are thermal-magnetic.  They magnetically trip immediately in short-circuit high-amperage conditions.  They trip thermally in an overload.  The amount of overload and the time it is under overload, as well as the ambient temperature, and the operating temperature of nearby breakers ALL affect the time it takes to trip the breaker.Which is fine because the overheating of the wire is what they are protecting and time as well as current work the exact same way here, which is why smaller CAN be used in lower duty-cycle applications, when cost makes a difference)The simple fact of all the variables may be why Lincoln recommends the fuses.  Strange, though.  They give a recommended breaker size, and not a fuse SIZE?  (referring back to post #1)
Reply:I checked over the Installation manual again and it says for 230/60V Input Voltage:Wire Fuse or Breaker size 80AIn the diagram it just shows the two super lag no rating.By Wire Fuse do they mean, Super Lag?
Reply:Maybe they left out all the commas and want 80A wire, 80A fuses, and 80A breaker?
Reply:So I am confused now after reading everyone's posts. My PM215 manual tells me to use #10 AWG for up to 100' run, and a 60 Amp breaker. Then wizard posts that I should have used #6 for a 50 AMP circuit. I wired it up per the Lincoln manual, with a 60 Amp breaker and #10 wire. I did not install a disconnect box or lag fuses. Do I need to install a disconnect and fuses? The outlet that matches the plug on the welder is 50 Amps.I don't want to burn down the house.Thanks,Mike
Reply:Wannabe, I am an electrician AND a weldor.  You wired yours the exact same way I would have wired mine.  Read Article 630 in the National Electic Code and it explains why a #10 wire is more than sufficient for your machine.Now, it is too small for a bigger machine that might use that same breaker, though, so label the receptacle well, and change the breaker to a 30A if you move out so nobody else does something stupid.
Reply:Your manual says the same as mine and says to use two super lag fuses and even shows the same schematic as mine on page A-3 of your manual. Can't be any clear than that. Plus if you don't follow the manufacturers installations and they found out you didn't hook it up as the manual says, you can be damn sure there goes your 2 yr Warranty on your machine if something fails on it.That's why I will hook it up as directed, no loop holes for them to say, well sorry.....your not covered. Plus having those super lag are recommended for a reason and I would't leave them out, they worked on my compressor and my have stop a fire.  Food for thought
Reply:MAC,Thanks for the info, but what about the fuses? Page A1 of the manual has a table with recommended input wire and fuse sizes. One column is titled "Fuse or Breaker Size (Super Lag)" and list 60 amps. Page A3 states "Fuse the two hot lines with super lag types fuses as shown in the following diagram". So I take it I need to install a disconnect box and fuses similar to what Candyapple did above. What size fuses should I install, 80 amps?Thanks,Mike
Reply:Okay, I just read through the electrical input section of the PowerMig 350 manual.They say fuses instead of breakers throughout.  Looks to me as if you are using a breaker you don't need the fuses.  They keep talking about fuseboxes as if this was 80 years ago.I have to leave for a while, but I read it some more later.Keep in mind that Lincoln is weird with their electrical advice.  I found it funny that they recommend to follow the NEC and then you look at their manual for the SP-175 and compare it with the manual for the Miller MM175, exact same class of machine, and yet Lincoln recommends #8 wire and the Miller says you can use #14.
Reply:Thanks for the help MAC. As an electrician, I am going to follow your advice and leave things as they are for now. If after you look into it a little more, and decide I need to install a disconnect and fuses, then I will do that.Thanks,Mike
Reply:PowerMIG 350:  I just reread its electrical section of the manual, including the specifications sheet.  I see nothing that shows needing breakers AND fuses.  Am I missing something?
Reply:PowerMIG 215:  I just read its manual's electrical input and specifications section.  It clearly says fuse OR breaker size of 60A with #10 wire for less than 100' and #8 wire for more than 100'.  Here, too, I don't see anything that insinuates fuses in addition to a circuit breaker.
Reply:Oh, and "Super-Lag" is just a marketing tool.  They must have some affiliation or paid promotion to put that in there.  "Super-Lag" is a brand-type of fuse by the Bussman Fuse Company, their brand of time-delay, apparently.
Reply:Hi MACI haven't done electrical work in years but I do have my copy of the 2002 NEC in front of me.   I understand what they are getting at as far as derating the conductors to a welder based on its duty cycle.    That is all well in good.I do have problems with this in a non industrial setting.    First safety should be paramount and I would be very concerned about what happens when the dwelling changes hands.    Signs are nice and you certainly should change the breaker back to the correct size, but signs get torn down and breakers forgotten thus leading to potential problems.    It simply is not something I'm comfortable with, even if the NEC does not want to distinguish between dwellings and commercial buildings.    The other issue that bothers me is that there are other devices that can be plugged into these outlets that may impact the safety of the circuit.    Plasma torches come to mind.   It is also very possible that in a home environment the outlet may eventually have two different welder plugged into it from time to time.    A Mig and a buzz box being a common combination.In any event the length of the runs in a home are not normally that long.   So there really isn't a huge cost difference between running cable rated for 50 amps and some rated for 30 amps.    It is simpler in my mind to wire the outlet for its rating.Now as to the overload devices that is another issue all together.    According to the NEC the conductors supplying a welder shall be protected by devices rate at not more that 200 percent of their ampacity.    Then the NEC goes into protection of the welder.    If you have your supply conductors protected at less the 200 percent of the max current of the welders primary then you do not need separate protection for the welder.    In any event the welder can not be protected by an over current device that is rated at more that 200 percent of the max current the welder can draw.     There is actually more to it than that, people should consult the NEC when concerned about a proper installation.In any event you can now see where Lincolns recommendations come from.   Take a SP175 for example.    Since this is a 20 amp primary machine Lincoln recommends a 40 amp breaker.   This takes care of requirements for protection of the welder according the the NEC.   Protection of the wiring is another matter and could potentially result in a different overload sizing for the conductors.    That is if the conductors are undersized relative to the overload protection for the welder.     All in all a bit confusing.   The goal is to require separate conductor protection, at 200% of the conductors rating, in the case of wiring that is undersized relative to the welder protection.In the end if you put in a 40 amp breaker I do not see where there should be a big problem with running wire sized for that breaker.   This eliminates the potential for things to be forgotten or the overloading of the circuit with other devices.   Sure in an industrial setting the cost of the wiring can quickly exceed the cost of everything else, justifying the adjustments to conductor sizes.    This isn't likely to happen in most home situations where the cost of all the other components required to install the branch circuit are likely to exceed the cost of the wire.As to Lincolns use of fuses, properly sized they are very reliable.    Can't say much more than that. ThanksDave Originally Posted by MAC702Wannabe, I am an electrician AND a weldor.  You wired yours the exact same way I would have wired mine.  Read Article 630 in the National Electic Code and it explains why a #10 wire is more than sufficient for your machine.Now, it is too small for a bigger machine that might use that same breaker, though, so label the receptacle well, and change the breaker to a 30A if you move out so nobody else does something stupid.
Reply:Originally Posted by WannabeSo I am confused now after reading everyone's posts. My PM215 manual tells me to use #10 AWG for up to 100' run, and a 60 Amp breaker. Then wizard posts that I should have used #6 for a 50 AMP circuit.
Reply:Or....you could avoid any confusion and run the installation like I did. I used 4 AWG wire, and an 80 amp circuit breaker for my Thermal Dynamics Cutmaster 101 Plasma Cutter. It called for an 80amp breaker but was using a 50amp plug. As far as I could grasp in my 2002 copy of the NEC, there is no problem with over-sizing your wiring and discarding the ability to de-rate the circuit. But the reason I did that is because I like to use simple logic. How in the heck would I know now if down the road if I was going to change plasma cutters? or use a welder in that circuit? And what if you sized it for a 40% duty cycle, but your buddy used your welder for 100% duty cycle and somehow, the welder didn't fail, but the wiring was now melted? screw that. It's easier to have a huge safety margin if you ask me. For that short run of cable it wasn't much more for the larger size copper. There....did I beat that dead horse back to life?Lincoln Power Mig 210MP MIGLincoln Power Mig 350MP - MIG and Push-PullLincoln TIG 300-300Lincoln Hobby-Weld 110v  Thanks JLAMESCK TIG TORCH, gas diffuser, pyrex cupThermal Dynamics Cutmaster 101My brain