Depends what pack you're playing, on infinity evolved for example there is immersive engineering hv connectors and wire which can convert rf to eu, but some other packs don't have any way to convert rf to eu.
That has powerconverters mod which easily converts back and forth.. I literally just typed "tekkit legends rf to eu" into google and this was the first thing that came up:
thanks when i usually search on google after things like this i put something like ,,how to transfer energy from a Reactor to a MFSU '' and i get 1000 forums about FTB
I use the energy node from extra utils for EU to rf, not sure if it works the other way, but I'd assume so
Bugger, what a troll too I mean there are so few EU power gen options out there why would you make it the one way no one really wants that much, but that's just my opinion
Seems limiting the way EU can be generated is quite intentional in many a mod pack. Frustrating. Makes IC2 even more of a pariah.
and a pain in the ass, on infinity evolved my buddy @PoorlySquare080 had to literally learn from scratch how to IC2, we're trying for an ME system and iridium is a pain to get .-. on the bright side i automated livingwood/livingrock