Usually the main issue for "Cables not working!" is actually a lot easier than it seems. Make sure you're not pointing the cable into the Output of the batbox. This can be known by the little "Dot."
Use a wrench (wiki It, if you don't know it.) and right click on the batbox somewhere else so the dot points to an open area\or to an area where you want to power something. the "Dot" represents the output. Here's an example: --- represents a cable. < represents output. > represents input. = Represents the power source. Here's what you're trying to do, most likely. =---<.
Another common issuee: the power in a cable drains over time. For example: I made a cable 20 long using a glass fibre cable. Because of it's efficiency, it doesn't lose any power but 1 EU. If I make a cable 20 long using Copper cable, it will lose 4 EU, 1 per every 5 blocks\units of cable.
Hopefully, this has resolved your issue. The cabling is very confusing at first, but it gets easier later on.