Strictly speaking, that round metal mounting bracket on the back of the fixture is supposed to be secured to an electrical box.
It can be a shallow box, but it's supposed to be a box. You must protect the wires. You want that new garage to still be there 10 years from now.
I can't really tell from the photo, but the right shallow metal box should fit within that recess on the back of the fixture without you needing to cut a hole in the siding. But if you have to cut a hole, then you have to cut a hole (if you do, rent, borrow or buy a holesaw for your drill big enough for the box).
You could attach the box through to the OSB with screws, although personally, I'd lay a 2x4 flat side against the OSB inside the garage, toenail it into the studs on both sides, and screw the box directly through the OSB into that 2x4. So a stiff breeze or errant basketball doesn't knock your light fixture off the wall. :-)
Drill a hole through the OSB and the 2x4 big enough to feed the cable and to accommodate the clamp that holds the cable in the box. The cable has to be clamped into the box.
Then attach the round mounting bracket that came with the fixture to that box, wire everything up, attach the light fixture to the bracket that you attached to the box. That's the way it's designed.
If it's a metal box, it has to be grounded (screwing the grounded mounting bracket to it will accomplish this).
You also have to secure the cable inside the garage as dictated by your local electrical code.
Finally, I'd use a dose of waterproof silicone or caulk around the box, and then again around the fixture itself after it's mounted, to make sure water doesn't seep inside.
Good luck!
Simply move it further towards the right on the wall (closer to the door) so that it clears the meter and you're good.
The clear space required is...
- Depth: 36" [NEC 2014 110.26(A)(1)]
In front of the box. As long as you're over to the right far enough that the meter isn't directly in front of the left corner of the transfer enclosure, you're clear.
- Width: 30" [NEC 2014 110.26(A)(2)]
Beside the box. This can be measured from the center or either edge of the box. You'd want to measure from the left edge of the box towards the door for your clearance. It also requires clearance enough for the door on the box to open to 90° (which it seems there is)
- Height: Not an issue [NEC 2014 110.26(A)(3) (Exception 1)]
Normally your clearance zone is from the floor/grade to 6-1/2' (or to the top of the equipment being installed, whichever is higher). I believe the eave there might not be tall enough, but exception 1 allows service equipment (less than 200A) to be installed at existing dwelling units with less than the required height. Although this could be up to interpretation and could pose issues with [NEC 2014 110.26(E)(2)(a)]
Also, per the wires and conduit, they are allowed to enter the clearance up to 6" in front of the box - which they appear that they would not. So they're also fine. [NEC 2014 110.26(A)(3)]
Best Answer
Get something installed to protect these conductors, before your car becomes permanently attached to your electrical service!
Considering that I spy an exposed SE cable below the meter pan, well in harm's way from errant cars and with only the utility's fuses protecting it from faults, I'd flag this installation as a violation of 338.12(A) point 1:
and 230.50(B)(1):
So, you'll either need to have this service-entrance re-run with a conduit, or see if you can get your local electrical inspectors to sign off on using bollards (i.e. concrete-filled metal poles) to protect the meter pan and service cabling as Machavity suggests. Or you could do both, if you feel like taking a belt-and-suspenders approach to keeping your electric meter from being a hit-and-run victim.