Im working at a school and we are changing out all the lights in the school. We are using the old whips to hook up the new ones. While installing we have just been turning off the switch so it will not be hot, but the neutral has a load on it. To try and get the load off I went around and switched off all the lights in the other rooms around the one im working in. I couldnt get rid of the load so I just went ahead and hooked it up hot but while I was working on it and wiring the neutral the lights in the room im in would flicker. I was wondering is the neutral being back fed? Is this what happens when you put more than 3 circuits on one neutral?