Should I install an electrical sub panel or expand my existing?

I am planning on #6/3 from the supply box to sub panel but was thinking I only needed #8 from the sub panel to the welder outlet.

I haven't bought a welder yet which is why I'm only pretty sure about that outlet I listed above. I guess I didn't post it but I'm planning to buy a Hobart 190 (specs) and didn't see any mention of plug style on their site.

Gonna use copper wire so no need to use any oxidation goo.
 
#8 is fine for the welder.
National electric code allows you to de-rate the wire ampacity by the duty cycle of the welder.
My MM252 draws 48A from a 200v supply at full rated output (300A). The duty cycle at 300A is 25% so in theory I could use 14Ga wire (good for 15A) on a very short run (to avoid too much voltage drop). I used 8ga THHN wire (typical for 40A) and it all works fine.
I also surface mounted my 100A panel and ran all the wiring (outlets, fan, welder, compressor) in conduit.

edit: to prevent flaming from the sparkies I'll amend this post to state that since this is wired to an outlet and not hardwired to the machine it may not meet code but will be perfectly fine to run your welder. The difference being that with an outlet, someone could plug in something that draws 50A with a 100% duty cycle and overheat the 8ga wire. I know I will never overload my outlet and if/when I sell the house I'll pull all the wiring.
 
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I cut out the sheetrock for the panel but am going to do the wiring for the outlets via conduit.

I'm going to put the 220 outlet pretty close to the sub to help keep the $$ low on the more expensive copper.
 
The main supply wire is going behind sheetrock to the new sub panel which will be flush mounted. All the wires leaving the new sub will be surface mounted in conduit.
 
now I get it. Just the way I installed mine.
For stuff on other walls, I ran a 1.5" conduit up to the ceiling with all the wires and came back down in several places with smaller conduit for the outlets. Attic space above my garage.
 
I looked at the home depot wire by the foot... copper 6/3 is 2.79 a foot while 2/2/4 aluminum is 1.26 a foot. To me I would rather go with the bigger wire (for less money) and be safe then spend more and have to worry about causing a fire that might kill someone, or damage thousands of dollars in property....

Your call on the this but my advise would be to go with the aluminum 2/2/4 and be safe....
 
frieed said:
now I get it. Just the way I installed mine.
For stuff on other walls, I ran a 1.5" conduit up to the ceiling with all the wires and came back down in several places with smaller conduit for the outlets. Attic space above my garage.
Click to expand...

Actually I didn't read correctly.

getting conduit out of the wall cavity will be a total pain. Put a piece of plywood over the hole and mount the panel on the ply. Bring in the feed from the back. Conduit will terminate into the sides/top/bottom of the panel. Much, much easier to do.

Come look at how I installed mine and discuss if you wish.
 
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I picked up the 2/2/4 aluminum wire for the sub and 6/2 copper for the 220 outlet. I was trying to find a cable clamp (I think that is what they are called) for the aluminum wire but wasn't sure if I bought the correct one. The thing I was looking for was what you lug on to the side of the panel to protect the cable as it enters/exits it. I bought a bigger one for "nm" wire thinking it might work. Is there something better to use for this?

I'm still trying to decide whether to leave the panel flush mounted or not. I'll decide that when I go start running the wire I guess.
 
Here is mine
_MG_3329_zpsd9293463.jpg


Surface mounting makes running conduit simple...
 
Great I got the one on the left. Good to know it will work. I was going to work on get things run today but got distracted. It's going to be a bit until I can come up with the money for a welder anyway so I'm not in a huge hurry.
 
Got some more progress on this and with that I have a few more questions. I'm sure they are pretty simple.

Here is the new box installed on the outside of the drywall. I used alum 2/2/4 from the supply panel to the new box. I haven't made the connections on the supply side yet. On the 4 sub connections I applied the anti corrosion goo before inserting the ends into the blocks then tightened them down. On the ground strip there was only one large block so I bought an extra one at lowes so I could get the white and the bare wires tightened down.

7ibrDlEl.jpg

Here is a look with 6/3 copper wires connected to a 50 amp breaker for the welder outlet.

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And here is a look down the conduit to where the outlet will be roughly 5' down the wall. You can also see the two other holes I cut to install this behind the drywall that I'll be filling back in. I forgot a couple of the transition pieces to go from the conduit to the box so I'll be picking those up tomorrow to finish up the outlet wiring.

Z7pYDERl.jpg

Questions:

1- On the breaker wiring, does it matter which color wire goes on what side? Where I have the black wire it says "common trip."
2- I'm going to add a regular 4 outlet box right below the panel. What size cable should this be? I was going to use the 6/3 but didn't have enough extra. The sub came with (5) 20 amp breakers and I'll be using one for this.
3- Does anything here look not great?

Thanks.
 
1. Doesn't matter. Common trip means if one leg is overloaded they will both trip.
2. 12ga wire will be fine for a 20a circuit.
3. White wire in the sub panel should be on the other side from the ground (right side). One buss for ground, one buss for neutral. On the 50a breaker for the welder and inside the welding receptacle you should tape the white wire another color, red would probably be best. That will indicate that it is a hot lead but not the same phase as the black wire. White is generally used for neutral.

Otherwise it it all looks great! Sufficient power in the garage is a must.
 
Thanks for the info. I ended using 10 gauge for the 20a breaker. I'll move over one of the wires to separate the ground and neutral.

Where do I find a ground block that will accept the large alum wires? The existing block is full and Lowes only had the small opening blocks.
 
on your panel. usually the black goes first then the red. but really doesn;t matter seeing they both are hots.
and the white and ground need to be on different sides like someone else already listed.

You can go to codale but they are expensive.. home depot is way cheaper... and instead of getting a lug to screw into the other side you can get a ground block that is like the strip but what you do is just bolt it to the bottom of the panel with a screw and then the box actually becomes grounded to all the conduit you run as an additional safety measure.
 
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