I placed led puck lights on each step of my stairway. Want motion detector switches at top and bottom of stairway. Circuit will be 12-2 power to first sensor. 14-3 wire to second sensor. 12-2 wire to lights. Wiring diagram shown in directions do not work. I tested sensors just one to a light and they work fine just not together. Need diagram assistance please. John

First, it is not a good idea to mix conductors. 12/2 is listed for up to 20 amps. 14/3 is listed for up to 15 amps. When the two sizes are used in the same circuit, the entire circuit is limited to 15 amps. To place 14/3 on a 20 amp circuit is a fire hazard.

Second, how can we help with your circuit diagram when you did not include the diagram.

Thanks for your response. I can change wiring if need be w/o a problem just tell me what I should run to be safe. I thought I tried to make myself clear the first time but I will try to do a better job this time. Power is coming from a bedroom light switch jumped over to first sensor with a 12-2 wire. I then ran a 14-3 wire to the second sensor. From the second sensor I just want to hook up to the string of puck lights that work just like a single light so when you get near the stirway on the top or the bottom the puck light come on.

Okay,

Let's start here at the bedroom light switch. Is it a simple snap switch with ON/OFF embossed onto the handle? Or is it a switch that has a neutral present?

If this is just a simple On/Off switch and there is no neutral present, in addition to the conductors on the switch, then you cannot us the switch as a power source. Switches interrupt the hot leg only, neutral is not used on a switch therefore it cannot be the source and return for a circuit.

I think I will just run a new wire from the breaker box. Walls are open so it will be easy to do that. Tell me how you would do it straight from the breaker and I will do that if it is the best way to do it. Thanks

Levi,
Don't get to excited about running a new wire yet. If I can get the right information from you I will try to walk you through this. A couple of basics first.
1)if you place a 20 amp circuit breaker in a panel, then #12 wire is the minimum the code will allow for wiring. Underwriters laboratory approves smaller wires for listed devices such as your sensors, but that is only for the sensors as they come from the factory, it does not apply your supply wires.
2)if you decide to use the existing wiring from the bedroom you have to be sure that the hot and the neutral are present at the switch. If there is only one cable with a black and a white wire in the switch box then you do not have the needed neutral for you project. If there are two or more cables in the light box then a neutral will be present and you can connect up to the power here. If there are more than two wires you could still connect up but there is a good chance you would be in code violation due to the code only allowing so many wires and devices in a box depending on cubic inch of box. So for the sake of keeping it simple there needs to be two romex cables in the switch box. No more -no less cables.

Once we have power to the sensors we need see the circuit. It could be they are just powering a low voltage transformer with the 120 volt power and doing all the switching etc. with the low voltage. If such is the case then the #12 wire can end where it connects to the transformer. We may need a GFCI here, but we will deal with that later. The low voltage is considered a different system and voltage and the size of the wire is dependent on load of the low voltage, not the 120 volt circuit breaker anymore. Let's get this far and go from there. If you can post a link to the device on the internet somewhere I will be glad to try and look it up and explain what you need to do. At this point I am flying blind and that isn't good when we have the possibility of connecting things to the wrong voltage. It is getting late here, so I don't know if I will be here much later. Good luck. Do what I can to help you, but I need to know a few things.

I appreciate it and I am not at the house I am doing this at so I will get back to you. When you have time check back say Sunday night or Monday and I will try to get all info you need. Thank You!