So, I have a few boxes from Volt that I need to crack open and start laying out sooner than later, but I had a few questions that I could use some help on (and hopefully will help other folks). I have a 300watt transformer that will be mounted in the garage, and I will be using approximately 10 spotlights for the house and 7 or 8 path lights for the walkway as well as 4 mini spotlights to illuminate some pillars. The thing is I plan on adding more lighting down the road to uplight trees and light landscaped beds (I'd guess approx 20 more lights down the road). With that said, how many lights can be run on one 12/2 line that homeruns back to the transformer? I purchased 4 junction boxes/hubs and intend on using a "star" and combination wiring method to try and neatly organize the wiring. For simplicity's sake, say I'm planning on running 5watt leds for each fixture. I thought I read 8 fixtures is ok, but is as many as 10 fine? With the "star" and combination wiring method I'm trying to keep distances for each fixture for one homerun relatively close. Also, when running low voltage wire through walls would you recommend something like 1" conduit or would 3/4" suffice? I figure I'll probably need roughly 5 12/2 lines for future needs and don't want to be caught shorthanded on space when I add wires later. I realize 1" is very large, but if you account for a 90 degree bend to turn the pipe down into the ground, it could make it tight. Any thoughts or suggestions are greatly appreciated!
Hi Mozguy, Welcome to the forum. Let's break down your question into its parts. We suggest a maximum fixture wattage load of 240W on your 300W transformer. We suggest a maximum of 100W on each 12/2 wire. Bravo! on your use of the junction hubs - they will reduce the number of field connections and simplify your installation. As for running the wire through the wall, you need to be very careful to select the conduit that complies with National Electric Code - also to make sure you run the wires attached to the interior walls according to code. You might want to get an electrician to help you there. Those wires can get very hot - especially when they are heavily loaded.
Thanks for the info. I was aware of the max load being 80% of the stated wattage but thanks for reiterating that. Regarding the wattage wow, I can't remember who told me ~8 lights but if I can run upto 100W that'd be great. I could consolidate the number of 12/2 homeruns to 3 or at most 4. Sorry if I wasn't clear on the electrical wiring. I'm talking about running the low voltage 12/2 cable through the wall to the transformer that will be inside the garage, not line voltage. I'm going to just drill a hole straight through to pass the wire through the brick facing into the garage. I don't plan on fishing low voltage wiring behind drywall. I guess if I only need 3 or 4 12/2 cable then 3/4" pvc might do the trick. I'm not sure if/what the NEC code is for low voltage wiring, but last I recall there are no requirements.
Mozguy, yes, I was referring to the low voltage wire going through the garage wall. Those are the wires that can get very hot - even causing fires - but only if the person grossly undersizes the wires. That's why NEC does have codes for running low voltage wire indoors and through exterior walls. I'm not an NEC expert, but believe that a metal conduit is required going through a wall.
Gotcha, thanks Steve. I'm going to stop screwing around and just stick a small piece of metal conduit through the wall and use a metal junction box on the outside like I'd do for a line voltage installation simply to cover my ass. I've done a fair bit of electrical work myself and best to keep the code police off my arse. I'm not sure the sprinkler wiring that was installed by a company is technically upto code either (they just drilled a hole in the wall and placed a piece of conduit outside, none inside the wall), but the risk is minimal and I won't get bent out of shape over it. Hopefully I can start tackling this project next weekend. Thanks again.
I just wanted to say thanks for all the advice here on the forum and throughout the website. I finally got the landscape lighting mostly done this weekend and it came out very nice (I think). I used 11 all star spotlights and 9 path lights. A few things I liked and thoughts: The 25' lead wires allows for less splicing and less headaches. I've bought box store lights and the short lead wires are just a waste of time. The junction boxes I loved. I didn't see the new style of junction boxes when ordering (with the clamp connectors), but I could see those being worth the additional cost. I ended up crimping ring terminals on the ends inside the junction boxes (a review or someone mentioned this) which was a great tip and then I just used small machine screws and nuts to make all the connections. This makes it easy to make connections and they're not as permanent as wire nuts with silicone. About the only "problem" is now I want to add more uplights for my trees and other landscaped areas. It's easy to go "crazy" with 40+ lights if you really wanted to highlight a lot of parts of a yard. Regarding a neat and tidy install. Is there any recommendation or industry standard when burying low voltage wiring? I know some people to go 8"+ down in the grass to avoid aerators hitting the wires, but in mulch beds is just a few inches down fine? I'm the only one that tends to do digging anyway, so I'm not too worried about someone hitting my wires. Thanks.
You're very welcome. Congrats on the initial install. Required low voltage wire burial depths are described in the National Electric Code. The general rule is at least six inches burial. It's a bit more when going under sidewalks and other hardscape areas. You have the mulch part backward; you need to bury wires deeper under mulch - not shallower. The rule under mulch is also 6-inch burial - not under the mulch surface, but rather, 6 inches beneath the hard ground under the mulch. Yes, tempting to put the wire shallower, but keep in mind that a time may come when you are not the only one tending to your mulch. A nicked wire in mulch can cause a fire.
