Cables don't connect. GalactiCraft 1.7.10 by Rockmacaca (https://github.com/rockmacaca/Galacticraft/tree/1.7.10) and recommanded Mekanism build 75. GalactiCraft is generating a config option for "Mekanism Power Ratio" though..

Update: Ok, so when I install BuildCraft, GC connects, but BC still doesn't.

Update2: I suppose it's a GC issue.