Landscape lighting wire rough in for future, what wire, how deep? Other things to consider?

Question

I am currently working on my landscaping and I have a concrete pour planned for the front paths.

I'd like to rough in landscape wire for future lighting. What kind of wire should I use, how deep should I burry it?

The lot is ~50' wide and the house is set back maybe 30' from the road. I have various trees and perennial plants planned. Before the concrete path is poured I was thinking I should have home run wires from my line voltage outlet to each area of the landscape where I expect I might want a light. The plan later would then just be to junction or have left enough slack to lay that slack to the final light location.

I am in Canada but I expect the low volt code requirements are the same in the US.

I currently have 4" and 3" sleeves ( just random pieces of PVC/ABS I had lying around ) that are 2' buried below grade at all places where the concrete paths are separating areas of the site. These sleeves run under each piece of pathway. These are to future proof for handling line voltage (120) or potentially adding a line for a car charger in the future - as I could use the sleeves to push through tech cable or conduit.

There are currently trenches for irrigation (1" or 3/4" pvc) for sprinklers that are 8" below grade.

Adding another set of conduit for low voltage lighting could probably use the same trenches as the irrigation. The problem I face having never done low voltage lighting is where to terminate the conduit - since I don't know where the lights will live do I just home run conduit to where I expect to put a transformer and have a home run of conduit from each lighting area to that location? Once the low volt conduit is run to the general lighting area is that enough of a conduit path? Assuming I can feed the low volt wire to the light area some minor trenching afterwards seems reasonable given my lack of a landscape lighting plan. Would I just duct tape the end up of the conduit until a time when I am ready to do the lighting?

Now since the low volt conduit would also be crossing the 8" deep irrigation piping do I go under or above? If 6" is the NEC code for low volt wiring then above?

I've added my irrigation conduit plan. The site is ~50' across the front and the house is ~30' setback. The different colors in the irrigation are different zones.

Answer 1

Conduit

Don't put in wires. You'll guess wrong.

With conduit, you can run multiple wires, change the wires for a larger size, etc. as needed over time. There are limits, but even 1/2" can hold several wires. If you want to play it safe, go up to 3/4" or even 1" and you'll have enough capacity to run power to a shed subpanel or whatever else you might reasonably need in the future.

You may even want to run two separate conduits. One for 120V/240V and another one for low voltage (12V for lighting, network cable, etc.) as they can't go together. Material (a few more sticks of conduit) is cheap, and the extra labor now would be basically zero.

Answer 2

Answer In the US and according to the NEC:

Low voltage lighting is limited to 25 amps and 30 volts maximum within these requirements the “low voltage lighting around your yard is required to have a 6” burial depth.

, now the kicker if you purchase a “lighting system” the wire can be on top of the ground in some cases because the manufacturer allows it.

Burial depth from table 300.5

Amperage 411.3

Low voltage 680.33.B

So I would pit in a piece of 1” conduit 7” from the surface this will allow you to even pull in monster #8 landscape lighting if needed for voltage drop.

Even if you know what you want it is a good idea to be able to repair it or upsize in the future.