Not sure if this is a issue fixed in the Minecraft 1.6 version but I am currently playing on the DireWolf20 1.5 v2 v1.1.3 pack and have noticed that the Power Switch Pipes wont let power through until there is a block update next to them. Easily dealt with by setting up a piston next to it but because I can't find any information on the issue I thought I would bring it to your attention just in case you were unaware.

yes thats fixed, Power switch pipe is fixed in Flow86/Additional-Buildcraft-Objects-Mod#43 (since its an ABO pipe)