Kinesis Pipe

Conductive Pipes are a class of pipes from BuildCraft that transport BuildCraft's energy, the Minecraft Joule (MJ). They are created by combining the original Transport Pipe with Redstone. Note that if more power is trying to go through a pipe, a bottleneck will form and the energy "wire" inside the pipe will become red to indicate it.

Older Versions
Before 3.70, the only Conductive Pipes were Wooden, Stone and Gold ones. Max MJ Traversing on Conductive Pipes was technically 9,999 MJ/t, because upon reaching 10,000 MJ stored, the pipes would explode. It was very hard to reach this limit, though.