[chandler48]

You have neutrals run throughout your house, as evidenced by the white wires. The only problem is that the power enters the fixtures rather than the switch boxes. The electricians used a switch loop to energize and control the lights, making no neutral at the switches apparent.

No you can't run a single wire outside the casing of the cable. It must be contained in the sheathing. It would be best to search for a smart switch that doesn't require a neutral. Today's codes require xx-3 cables run from fixtures to switches with the white wire capped off for such a use as yours.

 

[chandler48]

OK, power comes from your panel via the black wire attached to the breaker. It is returned via the white neutral wire. Those wires go to the light fixture in the ceiling. If you had no switch, the light would stay on all the time because there is no control. Installing a switch loop, incorporating the white (taped black) and black wires to the switch make and break the connection allowing you to control your light. There is NO neutral at the switch if all you have is two wires.

 

[chandler48]

I want to know where all these DIY guys get the software to draw such nice diagrams.

Yeah, mine look like a 3 year old with dull crayons and a fidgety hand.

 

[chandler48]

I often copy the OPs image and then modify with paint.

I try that, but it copies in an incorrect format, not JPG or PNG. I can't recall, but it doesn't let you post it after it is modified.