On Mon, 19 Sep 2011 06:47:01 -0700 (PDT), DerbyDad03
wrote:

I am in the process of wiring an 8 x 10 storage shed for a light
fixture and an external AC receptacle. The receptacle will be for the
occasional power tool, radio, etc. No table saws or anything like
that, just small tools and other electrical devices that might be used
in the back yard.

Here's my plan and questions:

I currently have a 20A circuit that provides power to a GFCI outlet
and 2 light fixtures on my deck, all wired with 12G wire.

The shed is about 15' from the deck.

I plan to run individual 12G wires (Black, White, Green) from the load
side of the GFCI to the shed thtough Schedule 40 PVC buried 24"
underground.

From there I'll come up through the floor of the shed to a STDP switch
which will act as my disconnect. Following the disconnect, I'll go
through the wall to a receptacle mounted in a weather proof box under
the soffit. I'll mount it high for extra protection from the weather
and to keep it out of the snow.

I'll also have a motion sensing switch inside the shed for one, maybe
two, light fixtures that will be inside the shed.

Questions:

1 - Does it matter where I put the disconnect switch? Does it have to
be within a certain distance from the door or floor? (Obviously I'll
put it where it won't get buried behind what's stored in the shed.)

2 - Once the wires come up into the shed through the PVC, can I
transition to Romex? If so, at what point?

Thanks!
The disconnect MUST be reachable from the open door, and you can
transition to Romex from any junction box, which must be left
accessible, providing the romex is protected according to code.
Myself? I'd bring the conduit right up to the disconnect box.