Can't plug in cable in prison

[DailyRich]

I'm in the prison at a closed gate, and there's a power coupling on the ground that obviously fits into a socket on the wall, most likely powering the gate so it opens. Only no matter what I do, it won't plug in. I've tried using the grav gun to rotate it so it's facing the right direction, but nothing works. Am I following a dead end here or, if not, how the heck do I get this thing plugged in?

 

[zapper]

If I remember correctly every cord after the teleporter cord in Dr. Kleiner's office is pull out only. I don't think you have to ever plug in any cords after the "Red Letter Day" chapter.

 

[Xac493]

I think that was for taking down a force shield, mabey you blew it off with a grenade before you even got to that section?