Re: Article 406.8-b
If you are reading the 2002 NEC, notice that 406(B)(2) only applies to recetpacles that are NOT 15 or 20A, 125 or 250 volt (pretty uncommon).
OUtlets under a covered porch would fall under 406.8(A) for a damp location. These would not require in use covers.
So basically: all 15 & 20A, 125 or 250V receptacles in a wet location do need in-use covers.
Steve