ok, so i set up a nuclear reactor at halfway to bedrock a bit under and to the side of my house, how am i soposed to move all that energy without most of the electrisity being lost..... ALSO, i sont understand the reactors output, how does it evaporate some cables the more uranium you put in it if its only increasing EU/T, i thought EUP is what evaporated things....
The way I see it, you are asking two questions. How to transfer energy over long distances efficiently, and why some cables evaporate when hooked up to a reactor, over other cables in relation to configurations of the uranium cells.
1. How do you transfer energy over long distances efficiently?
Short answer: Use Glass Fibre cable, or set up High Voltage transformers and run EV cable.
Long answer: EU loss is measured in the packet over a given distance.
Fibre cable is able to handle High Voltage (512 EU/t) and it has the least resistance/power loss of all the cables. But it is fairly costly to produce this cable. A somewhat cheaper method is to use a High Voltage transformer ( 
) that can handle EV on each side and throw down some 3x Insulated EV cable. While this cable has ridiculously high resistance ( 0.8 ), it is able to transport energy ticks of 2048. So if you want.. say.. an efficiency of >90%, you can have your reactor a little over 250 blocks away.
If you wish to look up various grades of wires, check here: ( Link Provided )
2. How is it some cables evaporate when you put more uranium in a reactor, over other cables?
To answer why cables evaporate, I would like to confirm that it's EU/t, and not EUP. Think of it this way.. Copper cables can handle packet sizes up to 32 EU. This means they can handle an infinite amount of packets at a time, provided that each packet is, at maximum, 32 EU. As soon as you throw an MFE or MFSU into the mix (128 or 512 EU packet), the copper cable will evaporate, as it can not handle the higher EU packet. You will need gold (128 EU) or Fibre/HV cable (512/2048 EU)
Now, to the reactor. From a reactor, the size of the EU packets it generates is determined by two factors: How many cells you use, and the configuration of the cells within the reactor. Let's say, for example.. you hook up a copper cable to the reactor. The cable is able to transmit packets of maximum 32 EU. This means you can have, at most, 3 isolated uranium cells (30 EU). I suggest using either gold, or fibre cable when generating energy from a reactor, as they allow for a greater range of safe-ish designs. And as a reminder, please plan your reactor design as it will save you many, many headaches! Here's a planner that I personally use for every single one of my reactors ( Link Provided ). I do not own this, but it has saved mine and many of my friends asses.
If you wish to look this up further, Look under "nuclear reactor" in the wiki ( Link provided )
Phew, long time answering this. If I missed anything, let me know!