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dieselscout80
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Welder / Wiring for Small Garage
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OP
dieselscout80
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MAX-24-Dean
Veteran Member
Will a 30 amp circuit with 8/3 work? yes, but if inspected it may get a correction notice.
MVP 210 gives a minimum conductor size as #14 copper (see note 4 on sheet). Edit: text moved from here to below.
HOB Multi-Handler gives a minimum conductor size of #12 copper (See note 5 on sheet) Or MC cable concealed in a wall if exposed to damage.
Edit in bold to indicate text moved to correct location: but must be rated for 75 degree C. Which would limit you to individual conductors in conduit. Or MC cable concealed in a wall if it is exposed to physical damage.
This will get you by an inspector if this is being inspected.
Personally, I would use the 240 volt option with #12 thhn in conduit with a 30 amp breaker for the Multi handler. Your mileage may vary?
Same for the MVP 210, but use a 25 amp breaker. Again, your mileage may vary?
Up the breaker size to the next size if they trip.
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OP
dieselscout80
Veteran Member
Pardon me not understanding your first comment.
Why would larger cable be cause for a correction notice?
Note the wires are being run inside the walls.
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MAX-24-Dean
Veteran Member
Why would larger cable be cause for a correction notice? Because it is rated for 60 degree C per Art 334.80.
Sorry about not being clear, Some inspectors just don't like seeing romex on a welding circuit.
See note 5 from the multi handler sheet about 75 degree C conductors.
Copied and pasted below for clarity.
5. Raceway conductor data in this section specifies conductor size (excluding flexible cord or cable) between the panelboard and the equipment per NEC Table 310.15(B)(16) and is based on allowable ampacities of insulated copper conductors having a temperature rating of 75°C (167°F) with not more than three single current−carrying conductors in a raceway.
If you look closely at the sheets from the manuals in my previous post, you will see that I messed up, as only the multi handler has the 75 degree C note for copper conductors. My error.
But in general, manufacturers instructions usually include verbage about the 75 degree C conductor between the panel board and the equipment. As in the note 5 above.
WranglerX
Super Member
Also NATIONAL ELECTRIC CODE (NEC) has special section for welding circuits that differ from your electric stove, air compressor, electric drier, well pump circuits.... Hard to believe a inspector would ding a installation for over sized wire....
D
Deleted member 371759
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Not how to do it, but how I did it. 30 amp breaker #10 Romex to 50 amp generic plug. I made a 20Ft extension cord from 10/3 from home depot. My welder draws 26 amps full out. Never popped a breaker, nothing has went up in flames yet, and I burn through 125cu/ft tank of argon every 25 or so days.
MAX-24-Dean
Veteran Member
There not looking at the oversized wire, but the 60 degree C rating for the wire. When a lot of welder manufacturers specify 75 degree C (or higher rating) wire for branch and feeder circuits to welders as the only wiring method allowed.
Manufacturers written installation instructions supercede the NEC.
I had more inconsistent dealings with inspectors (in different juridictions) concerning welders than any other install I did.
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30 amps will work fine on 8/3 even on 10/3, but if you are running 240v use 8/2 or 10/2 either with ground, we never count the ground in the conductor count, also voltage drop won't need to be considered until over 125', and at 240v 8/2 with ground would take VD off the problem. Was electrical contractor for over 40 yrs in rule rich CA.
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dieselscout80
Veteran Member
I had 8/3 wire (3 insulated wires & a ground) and I have a Hobart plug adapter to go from a 4 prong (dryer type) plug to a 3 prong plug.
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