*** Garage Sub Panel Question

[mp333]

OK. I have updated my original post. It was late last night when I posted....

Hope the layout pic and the pdf for panel's break down is help full. I also have two other sub panels. One next to the main panel and the one for the pool #2 is on the opposite end of the house.

I am looking to install a 80A sub panel in the attached 3 car garage to power a 240v Heater, Compressor, 110VAC lift, EV charger and couple 20A outlets.

The Panel would be fed from the main panel with Copper Romex NM AWG-4/3 & AWG-8 ground cable.

I have couple questions that I am not finding answers to....

The sub panel is going in the finished attached garage. Above the garage is the master bedroom. I have no access above the garage. I am looking to surface mount the sub panel for obvious reasons. I do not want to cut the dry wall as the branch circuit will be going across three bays.
The two studs are just for illustration in the pic.

Do I need to mount a plywood behind the panel? If yes, does it need to be painted?
If I mount on to plywood (orange) the sub panel outlined in yellow would be mounted in the center.

If I do not need the plywood. I can only get the right side of the (gray) sub panel screwed on to the stud#2 as shown in the pic. The left side would not have any stud to secure. How do you secure the left side of the panel? Can you the butterfly bolt anchor type on the left side of the panel. The panel would be secure with two butterfly bolt anchor and the two screws into the stud on the right side.

Also what is the minimum distance you can have between the edge of the panel and window. What is the code?

Also the generator feed is not wired in. I have a spot for it on the main panel. I plan to do that with an interlock switch.

Thank you

 

[matt_i]

I believe the panel must be mounted "securely". If you don't like plywood then you could use strut channel (unistrut) and spring nuts and screw the back side of the channel to the studs, although that's 1-5/8" thick vs 3/4" thick for the plywood...

One practical problem is that the mounting holes in most panels are not in the middle, they are near the outside 4 corners.

 

[tyme2par4]

If you don't want to use plywood, you could simply use a couple 2x4s run horizontally between the 2 studs and securely nailed on each end.
As matt_i said, it has to be securely mounted, and 2 screws on 1 side won't cut it.

edit: Re-read and noticed it's finished. In that case, A heavy duty drywall anchor on one side may be adequate if you hit the stud on the other.

 

[CNGsaves]

Need MORE Information . . .
. . . . Attached or Detached garage ??
. . . . What size wire you plan to use for 80A subpanel ??
. . . . Where is power coming from ??

GJ Sparky's will give you all the details once the whole picture is clear.

Also . . . . no such thing as 110/220 . . . . standard is 120/240v !!

 

[tyme2par4]

Need MORE Information . . .
. . . . Attached or Detached garage ??
. . . . What size wire you plan to use for 80A subpanel ??
. . . . Where is power coming from ??

GJ Sparky's will give you all the details once the whole picture is clear.

Also . . . . no such thing as 110/220 . . . . standard is 120/240v !!

I'm not sure if any of those details are pertinent to the questions he's asking...

 

[Smoker]

I just flush mounted mine between 2 wall studs. The sub panels are designed to fit into the space between wall studs framed 16" on center. I wouldn't mess about with ply or such. Flush mounting the box all the wires are tucked in between the studs nicely too.

 

[mm08822]

I would cleanly open up the existing stud bay and put a new stud in at 16" oc. This way you can secure both sides of the panel properly. Also put a 2x4 or 2x6 about 10" above panel (in stud cavity)flat against the sheathing to act as a nailer for cable staples. Maybe even same for below panel.
When you replace the drywall add nailers to the inside edge of the existing studs so you can secure the cut out drywall.
If you choose to tape and finish the drywall joints, consider an access panel above/below for future needs.
This method will let you hide cables for a neater look than surface mounting.

 

[matt_i]

If you "bury" the panel, then connecting to surface-mounted conduits is going to be more detailed work down inside the cavity.

If expansion or full-er utilization of the panel is eventually going to take place its going to look very cobbled or have lots of junction boxes required to connect additional surface mounted conduits. Or simply strip off the drywall and run conductors within the wall and replace the drywall.

If it were me I'd surface mount the panel, the plywood is a very small effort compared to the ease of bending EMT or gluing up PVC that can all take place on the surface thereafter.

An alternative which I have used is to go straight up from the breaker panel with conduit into the attic area, and then come straight down to where receptacles are needed, again all running on the surface. There's sort of a "trunk line" conduit in the attic with Ts glued in appropriate places. But all horizontal runs are done out of sight, slightly more visually pleasing. I rotate/orient the PVC so the lettering is against the wall and just the grey pipe is exposed. Working in the attic is never a pleasant temp, so there is also that "cost" to be considered.

 

[Cmreschke]

I'm not sure if any of those details are pertinent to the questions he's asking...

They sure are, if your nosey with nothing to add.

 

[CNGsaves]

They sure are, if your nosey with nothing to add.

^ ^ ^ Well it does if OP is installing in finished garage, and doesn't appear to want any holes what-so-ever in sheetrock. However, that is inevitable and his overall location may not even be a good one next to window. If all his wiring will be surface-mounted in conduit, lots of things to consider beyond just attaching to the wall. Often it's beneficial to cut strip out of sheetrock around the garage to add circuits, etc.

Overall, might be better to move subpanel to different location due to ground rods that may need added (ie detached garage) outside on exterior wall - - may not apply as looks like OP is indicating it's attached garage.

Also, benches are often put in front of windows, so OP may have problem with obstructing the panel, along with problem of it being in the corner. Often best spot for panel is next to door so it's readily accessible and won't get covered up.

GJ Sparky's will provide guidance once the whole picture is clear.

 

[mp333]

I have updated my original post with pics and panel's layout... Hope this helps. Thank you all.