I've been told by an electrician that in order to add an exterior porch light, he needs to run a long wire and put a junction box, etc, etc. it seems so uneccesary to add one small LED light (5watts). There is a small bedroom on the other side of this exterior wall with an outlet just below where I want the light. It's on a 15 amp breaker. Is there a reason why I can't tap into that plug and use exterior wire run up behind the siding and power this light? I don't want to do anything unsafe of course and I don't live where codes are an issue but I still want to be safe. Thanks for the feedback.

 

I wouldn't run it behind the siding, but you could certainly run it up inside the wall to a proper electrical box mounted from the outside. Then install the light to the box.

How will you control the light?