DIY lighting safety hazards?

I've been putting together a T-8 lighting system inside a store bought wooden
hood for my 55 gallon tank (I've already posted 2 questions about it). I'm
almost through getting all the materials I need and about halfway through
installing everything. The reason for this post is that I've become
increasingly concerned about the possible dangers associated with this sort
of thing. I know very little about electronics and lighting, and have had to
ask the people at Home Depot for a lot of assistance. Overall they've been
helpful, but they really don't seem to be able to understand what it is that
I'm doing. They have a lot of trouble imagining endcaps, wiring, and ballasts
that are not all completely enclosed in a metal box (as they would be in a
fixture or shoplight). I have heard the words "fire" and "dangerous" from
them more than once. I don't think anyone on the list has ever mentioned
having their DIY lighting cause a fire, and what I'm doing doesn't seem too
different from the systems people have described. So let me give a
description of specifically what it is I'm doing, and perhaps someone can
tell me if something's not right. I have a wooden hood (around 50" x 14",
pine painted with a walnut stain) with 4 sides and a one-piece lid. On each
14" end of the inside of the lid, I have screwed in a strip of wood (cut down
from a 2x4). Screwed into the bottom of each strip are 5 endcaps, lined up in
a row. They are positioned so that when the bulbs are placed in them and the
lid is closed, the bulbs will be just above the glass cover on the tank. I
have two electronic ballasts (that each run 2 or 3 bulbs). I am planning on
screwing them into the underside of the lid as opposed to having them located
in a remote location, like the stand or the floor. One will be close to the
right row of endcaps, one close to the left row of endcaps. I'm doing this in
order to minimize the amount of wire needed. They will be in direct contact
with the wood, so will heat generation to the point of fire hazard be a
potential problem? Something else? In between the ballasts will be a metal
gounding box, also screwed into the lid, in witch as many of the wire
connections (with wire nuts) as possible will be. I was told that all wire
connections needed to be inside a grounded metal box (although it is not
possible to do this with the endcap connections, is this a real problem?).
 Out of this box will come the electrical cord or cords that will plug into
the wall socket. The Home Depot guy said I should get a three-pronged
extension cord and just cut it and connect the appropriate ballast wires to
it. Since I have two ballasts I assume I'll need 2 cords, Yes? I will get
some kind of material to act as a reflector. It will go above the bank of
lights obviously, but will be below (hiding) the ballasts and gounding box.
Another thing they seemed real spooked about was "bare" wires. The wiring of
course has colored plastic or rubber coating on it, but they seemed to think
that they should all be in a plastic conduit for additional safety, although
once again this is not possible with the endcap wiring. Any comments?

											Thanks for any help,