[OP]
Member
I am moving into a new garage w/ 220 items. The welder is a HF (Don't judge me) vulcan 220. I have included what the specs say. My confusion is the manual also says that a 20A breaker is acceptable. Perhaps I am mis-interpreting current input as output as required current capacity?
1. The compressor says max current draw is 24A, why does it require a 40A breaker?
2. Am I mis-interpreting the current input as output data and is the 20A breaker ok for the welder?
Thanks much guys
Dave
Member
Every 220 series class welder I have used all had at least a 40 amp and many times a 50 amp circuit. What ga power cord is on it? You can dial the welder way down output amp wise but the circuit should be designed to handle max amp requirements.
Guest
Your load isn't supposed to be more than 80% out the circuit I believe.
Member
Power Input 120 VAC / 60 Hz 240 VAC / 60 Hz
Current Input at Output 20.8 A at 100 A 25.5 A at 200 A
Welding Current Range 30 –140 A 30 –220 A
Rated Duty Cycles 40% @ 100 A
100% @ 75 A
25% @ 200 A
100% @ 115 A
Maximum OCV 78 VDC
Weldable Materials Mild Steel, Stainless Steel
Aluminum (with optional Spool Gun)
Welding Wire Capacity Solid Core: 0.025"/0.030"/0.035"
Flux Cored: 0.030"/0.035"/0.045"
Wire Speed 50 – 500 IPM
Wire Spool Capacity Up to 12 lb spool
TIg
Power Input 120 VAC / 60 Hz 240 VAC / 60 Hz
Current Input at Output 20.6 A at 125 A 15.6 A at 175 A
Welding Current Range 10 A –125 A 10 A –175 A
Rated Duty Cycles 40% @ 125 A
100% @ 90 A
30% @ 175 A
100% @ 105 A
Maximum OCV 78VDC
Weldable Materials Mild Steel, Stainless Steel, Chrome Moly
Stick
Power Input 120 VAC / 60 Hz 240 VAC / 60 Hz
Current Input at Output 19.5 A at 80 A 23.7 A at 175 A
Welding Current Range 10 A – 80 A 10 A –175 A
Rated Duty Cycles 40% @ 80 A
100% @ 60 A
25% @ 175 A
100% @ 100 A
[OP]
Member
Isn't that pic I posted? I am trying to interpret what the manual says and the possible contradictions.. I do not have the welder yet.
Member
I dont see a contradiction. Welders are transformers that switch voltage to deliver more amps to the work. The conductors they use will consume wattage so its not a perfect watt=amp*volt. Wire and circuit size and voltage limit the "transformation" options you can select. So the more amps you can supply at a higher voltage will allow you to select a lot higher amps at the lower voltage to tranforms too. Heat and its dissipation is a size of circuit and wire size as well and both play into the duty cycle which is the number of minutes you can run the machine before it must reat.
Its s nice welder btw. Dont downplay it. You will enjoy it!
Contributor
Stick welder outlets have their own NEC rules. Yours needs at least 30 amps/240 volts which is a dryer outlet. personally I would supply it with at least #8 and 50 amps. Better would be #6 and 50 amps so you can upgrade to mig or tig which follow standard NEC amp load rules. I would also throw in a neutral just in case.
NEC breakers are rated to be 100% duty at 80% load. But stick welders are rated as 50% duty cycle. I have no idea if inverter welders are rated any different per the NEC.
Bill D.
Contributor
The compressor requires a 40 amp breaker because of the starting surge. Motor draws much higher current for a short while when first starting, and would pop a smaller breaker at startup. So you need a 40 amp breaker and that means a minimum of #8 ga wire.
The welder draws 25.5 amps at 220 volts when the welding current is 200 amps. A 40 amp breaker and #8 wire would work for that as well, but as others have suggested, going to 50 amps and #6 wire is little extra cost and may be worth it should you upgrade down the road.
Those wire gauges are for fairly short runs. If runs will be more than 30 or 40 feet I would go to next larger wire (smaller number). Hope this helps.
[OP]
Member
The contradiction I am referring to is where it says to plug it into a 20A 110/220 breaker (For the welder, and then later it says it draws a max of 25.5A @200A in TIG) which seems to be the highest current consumption listed.. I included that screen shot. Paul, where did you find the startup current spike? Or do you just calculate it based on an equation of some sort? Also I'm curious as to why it says in the attached image that it just has to be connected to a 25A current supply and it stated a full load of 25A, they wouldn't take into considering this start spike? Isn't that the purpose of a start capacitor to help w/ this current spike? Just trying to understand what all of this means. The biggest issue I have here is I have finished walls in this garage and I don't think I can fit 8AWG into it w/ the other outlet circuit 12AWG wires feeding other outlets in there as well.
Last edited by Dave Brunner; 04-30-2018 at 12:40 AM.
Contributor
Welders have their own specific section in the NEC, Article 630. Wire and breaker sizing for general purpose circuits don't apply to welding equipment.Originally Posted by Dave Brunner
Moderator
Dave,
From your first message it appears that you have both a big air compressor and a welder to connect, right? On two different breakers?
I just checked my shop. It looks like I ran #6 cable from a 50 amp breaker to a 50 amp receptacles in my little welding room in my shop and another #6 from a separate 50 amp breaker for my 5 hp air compressor, both over 40' from the panel. It might be more than needed for many welding operations but all my welders and the plasma cutter have 50 amp plugs so that made things easy and gave plenty of capacity for the future. (I have MIG, TIG, and stick welders)
If confused about the requirements, maybe visit the store and look on the electrical plates/labels on the devices, if possible. Some manuals are horrible, outdated, and inconsistent.
Also, the 120/240v confusion might have another reason. My Miller MIG and TIG welding machines are dual-voltage and each came with two electrical plugs, 15 amp 120 and 50 amp 240. The quick-connect plugs on the end of the power cords can be swapped to operate on house current if needed, great for using somewhere that doesn't have a 50 amp receptacle. Both simply operate at a reduced capacity when run at the lower voltage. (The plasma cutter and stick welder are 240 only.)
I think finished walls are a bummer in a shop. I paneled my shop with 1/2" plywood held with screws so I could access the insides of the walls if needed. If you have sheet rock perhaps you could cut out a strip around the shop, wire as needed, then replace it with removable sections.
JKJ
Contributor
That welder will run on 120 or 240. If you run it on 120 it will max out at about 80-120 amps welding current, depending on mode. I assumed you would want to run it on 220 to get the full welding current capability. The 25.5 A input with 200 amps output is definitely running at 220. The Harbor Freight specs on the web page show the max welding current available for both 120 and 240.
It's true that NEC allows factoring in duty cycle when calculating the wire gauge and breaker rating for a welder. If this circuit will only be used for the welder, you could save a few bucks on wire. IIWM, I'd assume I'm going to want to plug some other 240 volt thing in there eventually, so I'd just size it like a standard 240 volt circuit.
As far as the compressor, No, starting surge is not usually factored in on the nameplate ratings. The starting capacitor provides more torque for starting; it's not there to reduce the starting surge. The reason the surge exists is simple physics....it takes more power to accelerate a load than it does to keep it moving at speed. That extra power need creates the surge. Because breakers don't trip instantly when current goes above rating, they usually don't trip on the surge, provided you use the breaker size recommended by the vendor.
Contributor
Bingo.
The circuit design will be based upon the machines current rating AND duty cycle. The NEC has specific rules for welders.
I'm in Canada, my home welder is installed with a 50 amp breaker, 50 ampere receptacle and #10 AWG wire as the welder is a 20% duty cycle rated machine.
Check with your local inspection agency for information on your location..........Rod.
Member
No comment on the welder...
As others said, the compressor might have start up current that will trip a 30a. My cyclone is 22a and Grizzly recommended a 40a. I ran it for a while on a 30a before putting in permanent wiring. It was fine on 30a. That was 5 years ago and it has never tripped the 30a. So I didn't need a 40a, you might. I "think" I didn't want to use 8awg wire; the breaker didn't really matter.
Contributor
For the welder I would be asking "do I want to future proof myself"? The answer is most likely yes. I would install a 50 amp circuit now and then if you want bigger you're all set. As for the compressor, go the 40 amp. There's more than just the current that will trip the breaker at play. Not all breakers are what's listed on them. It's confusing but it has to do with the code and the load. There's bot a continuous and non continuous load so it's possible that a 30 amp breaker will trip at a lower current so by stating 40 amps they are including some headroom. Often you'll find 120v tools that draw 13 amps but not many that will draw 15 amps. That's because 13 amps will work in any 15 amp circuit.
I made the mistake of wiring it for what it needed. It's a single stage 5hp Speedair but it has a small 5hp motor and it only needed a 30 amp circuit. Sooner or later I'm going to upgrade to a 2 stage compressor (either 7.5hp or maybe even 10hp). When I do all the wire will need to get removed and new larger gauge installed. When I installed the compressor there was nothing in my garage so it was pretty easy. Now, not a couple years later, it's going to be a pain. If you are sure that you will not go bigger then I would go the 40 amp.
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