If there is absoluely no way to run the lines without having to make any
joints in them, then silver solder is a must. If you use anything else,
including flare fttings, you are just begging for trouble. Pressure test
the lines afterwards just to be safe, so just in case there is a leak at
a joint, it can be located and repaired while still accessable. Also, in
pulling the lines, be sure to carefully unroll the lines. DO NOT try to
pull them off from the edge of the roll, like stretching a coil spring.
You are guaranteed to kink them if you do. I have had more than one
helper do that, when I told them to feed me the lines as I pulled them
into the attic. I could have strangled them. Best bet-- do not try to
run them by yourself, and get a good dependable helper. You are not
real clear as to the electrical you are talking about running. Is this
for a gas furnace in the attic? If so, a 20 amp circuit with #12 should
be fine. Or are you talking about a line for the outside unit? If so, do
yourself a favor and run at least #10. Good luck Larry