Normal placement of your new sub panel will be down in the basement directly beside the existing electric panel.
Mounting a sub panel to a concrete basement wall.
If it s my choice i ll mount a panel directly to a concrete or block wall.
I usually use tapcons.
Since the sub panel is only 14 wide i will still have at least 3 of space between it and the main panel as well as between it and the adjacent wall.
As stated above most if not all panels have dimples in the back of the can to provide a bit of space from the wall.
If the back of the panel was flat i d definitely use plywood.
Very low water table area.
This just makes sense because you connecting the sub panel directly into the existing panel.
Just a drill and a piece of wood will.
Then remove the tape.
The basement is finished but foundation walls are bare concrete electrical stuff is surface ac cable when it needs to provide outlets and devices on foundation wall.
Tape a one foot by one foot square of plastic sheeting plastic kitchen wrap will do to the concrete wall in your basement with duct tape and leave it in place for 24 hours.
I am showing a cheap trick when you don t want to spend the money on expensive dowels or specialized mounting devices.
And the shorter distance between the two panel means a cheaper installation.