Does this wiring look normal? If so, how can I connect a porch light to it?

Question

I'm getting ready to (finally) connect a porch light for my outdoor office. The overall wiring looks like this:

1) A sub-panel outside feeds a circuit into the shed:

2) The line goes from the shed to an outlet and then a set of two switches:

3) One switch is intended to control a port light. The other switch is intended to go to an overhead light:

4) If I examine the junction box where the porch light is, I see this:

Specifically:

• Two green wires (ground) connected together with a wirenut.
• To white wires (neutral?) connected together with a wirenut.
• One red and one black (hot?) connected together with a wirenut.
• A single black (hot?) connected together with a wirenut.

The wiring installation instructions are remarkably sparse. It's one page that literally just has this:

So, I have several questions:

1) Which of the two black connections should I attach the black fixture wire too? I would assume the single black supply wire?

2) Can/should I attach the white fixture wire to the set of two white wires (making it a set of 3)?

3) The ground wire from the port light is quite literally bare wire/cable. Should I attach that to the green bundle? Or is that not appropriate?

Answer 1

There is no way to tell what to connect to. It depends on how they wired it. I think it is safe to assume you should connect to the single black since it is in that box by itself like that. And yes, you would connect to the white and green with the other two wires. The instructions are not sparse, they show what you need to connect to. They do not know or care how your house is wired, nor should they. I will say, that box for the porch light is NOT appropriate. That is a collar box meant to mount onto an existing flush box. The wood of the logs is exposed to the back side of the box.

I also see a hole in the back of that collar box. Is this new light meant to be inside or out? If outside you'll need to replace that existing Wiremold collar box with a regular box, then run a cable from the back of the box into the back of a flush box outside.

Answer 2

If photo #4 is the place you want to install the new light than wire the white wire from the new light to the two white wires and the black wire from the light to the single black wire. First attach the ground from the new light.