When we filmed on location inside, lighting was needed constantly.
Lighting meant power cables, plugs, those orange boxes (RCD's I think) and of course the lights.
For reasons I cannot explain, they're named after hair-colours. "Redheads", "Blondies" and "Dedos", okay maybe Dedo isn't a hair colour, but the others are!
Blondies or aka the big ones are very big and very hot. At one point we're trying to set up this silhouette in a doorway shot, so to get sharp edges around the actor we need an awful amount of light behind him. As I was helping set it up, I was put in for a dummie to see how the shadows looked, I got to feel first hand how hot it got, very hot.
Lights are hot, it burns the plastic gels, it makes it hurt if you touch the metal and it sets off fire alarms as we learnt. The 2nd A.C. commented "oh I thought it would give us trouble" when he saw the fire alarm, the heat triggered it.
So the owners of the property can be assured that their fire alarm worked just fine.
Lights also have a habit of getting in frame, something I found out again later when I was editing the film.