Hi all... I'd really like to take on this project myself. I'm estimating that I will have (10) 5W lights in the front and (12) 5W lights in the back. I have 1 GFCI receptacle on the back of the house and that's where I was planning on putting the transformer for everything. Looking to run 12/2 wire.

I need help figuring out how to best run the wiring to the front from the back. A rough estimate would be around 450' of wiring including everything.

I have attached a rough idea and where the lights will be (yellow dots) and transformer (red square).

Any comments would be greatly appreciated!

 

Low voltage wire really doesn't like being run long distances. The voltage drop is significant over 50-100 feet. You need to work on limiting the distance from the transformer to the last light fixture.

This probably means a separate transformer in the front of the house, with a new GFI receptacle at the front. Also, those few lights that are way out from the house, you may want to consider other options. You can run a heavier gauge wire, but you might have a less bright light.

What are the distances from the house to the furthest fixtures?

 

Thanks for the reply. In the back, the furthest fixture would be ~90' from the transformer location in a straight line.

 

You definitely need two transformers....... one in the front and one in the back.
Your 100' runs with #12 wire with a 50w-60w load should be fine.

Your loads are low. You can use two small >100w transformers.

 

Thanks @PJmax... I don't have an outdoor receptacle in the front so that's going to have to be added. How do you suggest actually running the wire in the back? One long wire or can I create a T connection near the transforer so there are two runs out to the yard? Can I connect more the one power source wire to the transformer?

 

Teeing and going in two directions is a great idea.
Can you connect two outgoing low voltage lines to one transformer...... sure.

 

Okay, I might try one transformer and wire it like this. Maybe a dual-tap transformer and use the 15V for the longest run?

 

All you can do is try it. Setting the voltage to 15v will insure higher voltage at the ends but the close fixtures will be subject to 15v too.

 

I think I probably will do just that by laying all the wire out and checking the voltage at the very end of each run. Would 15V be a problem for the fixtures that are closer to the transformer?

 

Make sure all the lights are connected when checking voltage.
If no load is connected to the cable..... what you have at one end will be the same at the other end.
The lights create the load that drop the voltage.

Incandescent lights may burn hotter and brighter on 15v causing more frequent bulb changes.

 

Thanks, all my fixtures are going to be LED.

 

If you are using LED's in all locations you shouldn't have too much of a problem with voltage drop.