When you hear the term "end-of-run" it means that is where the circuit ends. So, an end-of-run switch is the last componentin the wiring of a circuit, and in effect, the wire feeding the switch is coming from the light fixture and not the other way around. How to Wire a Light Fixture to an End-of-Run Switch | eHow Is this answer helpful?Thanks!Give more feedbackThanks!How can it be improved?How can the answer be improved?Tell us how How do I wire a switch at the end of the run (switch loop Sep 15, 2008The light switch is located at the end of the run, which is at the top of the basement stairs. The wiring is in place but can be changed if required (for instance, changing from 12/2 to 12/3 as I How To Wire a Switch - Switch and Light at End of Circuit The easiest place to wire a light switch is at the end of a circuit. This does not mean that you should plan all your circuits so that your light switches are necessarily at the end. A light in the middle of a circuit really isn't that much harder.