Hi,
Just a small point, which I'm sure has been covered elsewhere in this site - in fact I'm pretty sure I found out about it here!
As the above poster quite correctly points out, fused wiring is really expensive. However, there IS a cheap(ish) way to aquire it, and increase your engineering skill as you do it!
Simply build Target Dummies, or Advanced Target Dummies if you feel like it. Set them off - next to the forge is fine, although you get some funny looks!
When they expire, you will be able to loot the wreckage for mats - which includes fused wiring if you are really lucky. The wool usually turns into linen, which is odd, but overall the loss is minimal. You will easily recoup your losses if you sell the wiring. As a bonus, if you do this while dummies are orange or yellow on your log, you will gain skill points for each dummy made.
I did exactly this on 03 Jan 07, post patch, and got 2 fused wires from 13 dummies. There are rumours that allowing high level mobs to attack the dummy increases the chance of a wire dropping, but I can't corroborate them. I got 1/7 from allowing the dummy to expire in the forge, and 1/6 from allowing a lvl28 spider to attack it, so no real difference for me. Maybe they have to be REALLY high level.
Hope this helps.