Subpanel and conduit question

[stimpee]

Ok, since I just scored a used Hunter alignment rack/lift for cheap on Craigslist (thread to follow in General section soon), I now have a need to run a subpanel up to my attached garage. I have been going back and forth between putting in a 100A panel vs 60A, but I think I have talked myself into 60, since I think 100A in an attached garage would be un-justifiable overkill.

I have 2 200A panels fed from the meter on the far side of my basement. I plan to run conduit from the panel will less stuff/load to the rim joist in the basement that adjoins the garage. If I poke a hole in that rim joist, it will come out within about 8-10" of the garage floor. The wall cavity above the location where I plan to run the conduit across the basement is an insulated, shared cavity between my dining room and the garage. If I go forward one wall cavity from that, it then becomes a garage/outside wall cavity, as the garage protrudes forward 6' from the front of the house.

So, my question is as follows: Should I bring the conduit out thru the rim joist, surface mount up the wall, and surface mount the electrical subpanel in the garage on the wall? Or should I go thru the sill plate from the basement and into the aforementioned "shared" wall cavity, then drill thru the stud into the forward wall cavity so I am on the outside wall of the garage and then go up inside the wall cavity and recess the subpanel?

I would much prefer the panel to be recessed, since I think it will annoy me to have it "sticking out" and bonking me in the arm, head, etc when I am working on the car on that side of the lift. I am not so concerned about getting the feed into the subpanel with it recessed. However all of my wiring that I plan to add in the garage will end up being surface mounted and wiring will be in surface mounted conduit as well due to current finish level of garage. I already have a good number of outlets on all garage walls, so the purpose of the subpanel is primarily to power the lift, provide a 240V socket for my welder, eventually supply a 240V compressor (currently will be supplying a 120V portable), adding some lighting, and probably supplying power to a new jackshaft opener and maybe a few electrical cord "reels" hanging from the ceiling. So there wont be many boxes on the walls.

My main concern is how do I then get the power OUT of the box in conduit and onto the surface of the wall? Do I need to make "S-bends" in the conduit and penetrate the wall, and then just make an effort to seal the drywall around the conduit? Is there a better way to do this?

Or should I just surface mount the subpanel and be done with it?

My subpanel is approx a 50' run from the basement panel. I am planning to use 6AWG individual conductors fed from a 60A breaker. I know I can use a smaller bare ground wire, but where do I find a 10AWG bare ground? Or should I get a spool of green #10 and use that for the ground?

Thanks for any help!!

 

[dragginbalz]

I have a similar situation and hope someone else chimes in.

I believe you can set the sub-panel recessed and bend some conduit (behind the wall) and enter a junction box (or a few) that are surface mounted, right by the panel. That will give you a place to make your connections on the surface and also a place to start running your surface mounted conduit.

Now I am not 100% you can do this, but I thought I remembered reading that somewhere once.

As I mentioned, I hope someone with more knowledge, chimes in.

Thanks

t

 

[sberry]

There is no reason not to add a 100A panel, most of them are that anyway, especially if you are piping it. I like to use a 90 or 100A wire if there is any distance even if I breaker it at 60 in the main, leaves an option should it be needed.

 

[mrb]

dont bend conduit to come through the drywall and into a surface mount box. Looks sloppy and is difficult to patch the drywall around. Run conduit behind the drywall from the panel into 4in square boxes mounted flush with the drywall. Then install 4in square box extenders on top of those with your surface mounted conduit running into them.

 

[rockwithjason]

I usually mount a 12x12x6 jbox half in and half out of the wall in situations like this. i run several conduit ******* from the panel into the box inside the wall and outside the wall i can run conduit how ever l like to the exposed area of the jbox. it would be much easier to use 6/3 romex cable in the shared wall cavity as it already has the ground wire integrated with the cable and is much simpler to install. use insulated 10awg wire for the ground if you go with conduit and individual conductors. you can use a 100a panel and breaker it at 60a. it provides much more room to work.

 

[dragginbalz]

I usually mount a 12x12x6 jbox half in and half out of the wall in situations like this. i run several conduit ******* from the panel into the box inside the wall and outside the wall i can run conduit how ever l like to the exposed area of the jbox. it would be much easier to use 6/3 romex cable in the shared wall cavity as it already has the ground wire integrated with the cable and is much simpler to install. use insulated 10awg wire for the ground if you go with conduit and individual conductors. you can use a 100a panel and breaker it at 60a. it provides much more room to work.

I like this idea (half in half out).

I have a dumb question. Will any metal box work as a junction box? Or are they all UL approved or something?

The reason why I ask is that I have a bunch of 16 gauge steel sheet metal and a box and pan brake. If I can bend up a box rather than purchase one for $50 (or whatever they are) I would like to do so.

I am not trying to be a cheapskate, I just like the idea of being able to make a box to my specific specs rather than purchase one pre-made, plus it won't cost me anything. IF it is not acceptable, I am perfectly fine with that, it doesn't hurt to ask though, right?


Sorry if I am hijacking your thread.

t

 

[mrb]

nope, cant make your own box -theyre UL approved.

I agree a half in half out pullbox is better, I posted my suggestion of 4S boxes and extension rings based on cost and the fact that the big box stores only carry one or two pullboxes and dont have any with no knockouts.

 

[dragginbalz]

I was just going to remove my post. I assumed they would have to be, but just thought I would ask.

I was just checking McMaster Carr for ideas. Something like this would be acceptable, right?

8X8X6


http://www.mcmaster.com/#7561k115/=2x257y

Thanks

t

 

[mrb]

yes, but mcmaster is not where you want to be buying stuff like that. I recently bought some 12x12x4 and paid $15ea.

 

[stimpee]

Wow, you guys are geniuses!

Seriously, thanks for the help with the stacked 4" box ideas or the larger Jbox. This solves my concerns over recessing the box but using surface mount conduit. On the box shown in that picture, are there knockouts that would also be outside the wall if you mount it half in, half out?

Also, for the suggestion to use 6/3 romex, I thought about doing that, but I still really want to put the run in conduit across the basement, and am not really interested in trying to pull romex thru the conduit.

I am planning to use either a 125A main lug box with 12 spaces, or may even just put a 100A main breaker panel in. The 100A panel will run me another $30-$40 over the main lug panel but will give me 20 spaces to work with, which is probably overkill for my needs.

The main differences other than the "which panel to buy" question above, is still between 60A and 100A. The difference in wire cost is nearly $3 per foot between #6 conductors and #10 ground, vs #2 conductors and #6 solid ground. So, $150 for that, and then the main breaker to put in my basement panel is less than $10 for the 60A, but nearly $40 for the 100A. So, I am just trying to decide whether the 100A panel is worth the extra $150-$200 for something that I likely don't really "need".

Another thing to add is that in a "perfect world", I will be building a detached garage/shop within the next 2-4 years that will be 1200-2400 sqft and will need more power due to size, HVAC, and a potentially finished second floor...

Keep the ideas coming! You guys have already helped immensely.

 

[mrb]

None of the smaller boxes are going to have knockouts arranged such that 1/2in-1/2out is going to work. That is why I suggested the 4S boxes. The steel pull boxes eat hole saws for lunch, unless you are only making 1-2 holes you really need to punch them or use a tungsten carbide hole cutter.

For the panel, get a main lug panel, you should be able to find a 125 with far more than 12 spaces...

 

[stimpee]

Ok, perhaps I will check the local electrical supply house vs the big box store...

Any recommendations or thoughts on the 60A vs 100?