Is it permissable to knock out a 2" hole near the top side of a outdoor panel?Plans are to knock out a 2" hole about 4" down from top on the left hand side and also knock a hole in the meter can to match so they will be even(appearance)Co-worker says no but we can`t find in nec.And also can I use pvc nipple or would it have to be water tight hub?

There is a product on the market refered to as a "myers hub" or possibly a sealing type locknut

check this site out also http://www.electrician.com/articles/myers.htm
http://www.electricaldeals.com/html/search.php3?column=AllenNum&search=MYER&source=ovr this site has an illistration of a hub

If you install two one on the meter and the other at the panel I don't see a proble interconnecting with PVC (two male adapters and a nipple to fit)

charlie P

312.2 Damp, Wet, or Hazardous (Classified) Locations.
(A) Damp and Wet Locations. In damp or wet locations, surface-type enclosures within the scope of this article shall be placed or equipped so as to prevent moisture or water from entering and accumulating within the cabinet or cutout box, and shall be mounted so there is at least 6 mm (¼ in.) airspace between the enclosure and the wall or other supporting surface. Enclosures installed in wet locations shall be weatherproof.
Exception: Nonmetallic enclosures shall be permitted to be installed without the airspace on a concrete, masonry, tile, or similar surface.

If a field-cut KO in a NEMA-3R enclosure wall is partially or completely above the elevation of factory KOs, a hub is most often in order.

The other concern is preservation of wire-bending space.

You can also use a sealing locknut and do what you are talking about doing.