I have a junction box in the ceiling that has two separate main wires coming in. One wire has a black and white plus ground. The other has three wires including red, white and black plus ground.

One of these wires are connected to a nearbye switched outlet. I am assuming it is the three wire (red, black white). My dilemma is I am trying to hook up a light fixture with white and black pus ground and don't know what connects to what.

I tried connecting the two blacks in the box to each other the whites to each other and then to the light fixture white and the red to the black of the fixture. This connects the light and it works however the only way to shut it off is the breaker. The switch does not work. As of right now I have taken the fixture down and connected like colors together, capped them and capped the red alone until I can figure this out. Please help.

Remove the switch and tell us what you see.

You will probably find one cable with a black and a white and another cable with a black, a red and a white. The black of the first cable will probably be connected to the switch and to the red of the other cable. The black of the second cable will be connected to the switch. The two white wires will be connected together.

If this is true, at the ceiling, connect the red to the black and the black to the black of the light fixture. Connect both whites and the white of the light fixture together. The outlet is not switched and is always hot.

If the switch is not wired this way tell us what you see.

Hi Harold,

Thank you for the reply. I removed the switch and outlet from the same junction box. There are actually 3 cables. One with black and white and the others with red, black and white. I tried to attach a wiring diagram that I think will explain this better than I can but I can't seem to do it.

Cable #1 has black and white
Cable #2 has red, black and white
Cable #3 has red, black and white

The whites are all tied together with a short black then connecting them to the outlet
Black #1 is connected to black #3
Black #2 goes directly to the switch
The switch has a small black joining it to the outlet
The reds from cable #2and #3 are joined and then there is a small black connecting them to the outlet

Hope this is helpful

Is this correct?

Hi Harold,

That is the right configuration. If it matters all three cables that enter the box are side by side and there is not one coming in at the bottom of the box like in the diagram. I really don't know if the outlets are switched. When I check them right now they are not but I don't know if that is due to me unhooking any wires in the ceiling junction box.

Plug something in the outlet and tell me if it works. I am trying to determine which wire the power is coming in on.

Yes both outlets work.

Ok, what you have is two circuits with a shared neutral coming into the switch box on the 3-wire cable on the right. The black circuit goes on to some other fixture via the 2-wire cable. The red circuit goes to the outlet then to the switch. It also goes to some other fixture on the red wire in the 3-wire cable on the left. This cable goes to the ceiling light box. The black wire in this cable is the one that switch. In the ceiling box, connect the black to the light fixture black. Connect the red to the black wire of the 2-wire cable in the ceiling box. This will send power to some other fixture. Connect the white wires of both cables in the ceiling box and the white wire of the light fixture together. Of course connect all grounds together. Light should function and be controlled by the switch.

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Thank you so much Harold. The fixture is up and working great. I really appreciate all the help.