Is there a possibility to use anything as a power switch?

Hi! I am just building a nuclear power plant. Currently I am working on the auxilliary power systems using railcraft steam boilers and a turbine. I wanted to have a little energy reserve in case I have to use the SCRAM of my nuke plant so that I can safely shut down all systems before there is a final electricity shutdown. Unfortunately, as the auxilliary power is connected to the main cables leading to my electric engine blocks (I mainly need buildcraft energy so I convert electricity into energy using the electric engines of forestry) and whenever my main energy from the reactor is connected to the engines, the auxilliary electricity storage will be emptied too. This is why I'd like to know if there is a way of connecting and disconnecting the electric current. Of course I could always set a cable block and destroy it, but I wanna have smething with style, so that I only need to activate a lever in the coordination central and it works.

Works! Thanks!