OK going off the top of my head here so I might be off a bit.
So you need to think of EU as packets of energy, same with torque (RU) actually,
You generate them in sized packets depending on your generation method, 16EU 48EU 64EU that kind of stuff, they travel to a device that uses them on wires, or you can put the device directly next to the generator for no power loss, 64EU out, 64EU in.
Evey block they pass through that isn’t using the energy you will lose EU, dictated by the wire and if its insulated in rubber I believe.
Now packets of EU, or RU can be combined into bigger packets. so with a transformer if you attach two batteries to two of its input sides, it’ll combine the two EU packets into a bigger packet that comes out of its output side, that means devices will receive the bigger packet all at once if you put it next to the transformer, or, you can run wire and will have a packet of EU that can travel longer distances before running out.
RU uses gearboxes rather than transformers but the concept is similar.
You can also reverse this and split larger packets of EU into smaller packets, think of it as a bus of people and they come out in little equal groups.