small wire puzzle

The way to look at it is that both the wires at the switch are black. you are just extending the black wire to the switch & back so you can turn off the light.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.