Large Scale Central

Advice on 12V DC distribution for lighting

Electronics Power and Sound
#1

Hey folks:

I’m wanting to wire up lights to my few existing buildings and get set up so I can incrementally add lights to new buildings as they are finished. I’m hoping that folks here will have some advice on how to conveniently, reliably, and modularly distribute an existing 12V DC feed around the layout. I have a current (no pun intended) plan but am not at all confident in it and know that many folks here have already solved this.

My plan is to use strip LED in warm colors (the kind where you can remove them 3 at a time and they come with integrated resistors for easy lights). They look like this:

That’s not really where I have questions. The question really is how to distribute power around the layout. My plan is to use standard DC garden power cable. Good points include reliable operation in a wet and corrosive environment. Bad is they are pretty large and wiring them together results in ungainly joints.

Here’s the existing wiring as put together by the landscaping folks (these power DC LED lights on my patio):

Note that there are about 3 or 4 wires, somehow attached to each other and then wrapped in what appears to be 20 feet of electricians tape. These were then buried inside that bit of PVC drain piping. Very elegant but it seems to work.

So I was thinking of using outside junction boxes as distribution hubs:

And then within that junction box, I’d use copper washers (1" diameter, cheaply available) as buss bars for +12V and ground, separated by a little contraption made out of PVC and styrene to keep the copper washers electrically separated. I vaguely am imagining using foam somehow to minimize water getting into these boxes.

So, what do you think? Is this crazy talk? Is there some other much more elegant method?

My next set of questions has to do with connectors so I can take buildings off as necessary.

Thanks in advance for any ideas.

#2

That’s pretty clever, Jim.

How extensive / complicated will your runs be? Just the 1 hub, 1 incoming, and three cables out? Or several hubs? Or…?

How will you branch off a buss to a building? Or will you have multiple hubs and one cable per building?

FWIW, I used Scotchcast splicing kits (rec’d by Greg E.) for my main DCC bus branchings, and they’ve worked well. But when it comes to repeated branchings to buildings, I’m all ears for something flexible / expandable / tap-off-able.

Best luck, keep posting, I’ll be curious as to what you wind up with.

Cliff

#3

Jim

For multiple splicing inside the box these work very well.

https://www.lowes.com/pd/Utilitech-10-Pack-Plastic-Standard-Wire-Connectors/999953378

As for disconnects for your buildings here is a suggestion. You could have them inside the building.

https://www.lowes.com/pd/IDEAL-5-Pack-Plastic-In-line-Wire-Connectors/50101792

#4

Thanks for the pointers, guys.

Rooster: Those look intriguing, I’ll have to wander over to Lowe’s and pick some up so I can play with them. Are you using them in your layout?

Cliff: I am thinking I can get up to 2 wires per hole in the junction box, so I can get 7 out, 1 in. My plan is to daisy chain these junction boxes sprinkled around the layout near the buildings, and run one wire per building. I have 4 areas that have closely packed buildings needing lighting (mine/sawmill/team shacks on one end, logging camp in the middle, city of Durango upper and lower, though the upper may have enough buildings for 2 hubs.

The copper washer plan implies that I’ll solder the wires to the washer. It is circular so it is easy to route wires within the box and I can solder each wire separately.

Is soldering a bad idea? Will it corrode? I notice that Rooster’s suggestion, and the 3M Scotchcast thing, seem to be quick connects with no soldering involved. The splice kit looks pretty intense (pouring a mold?). How much of a pain is that, Cliff?

#5

Jim Rowson said:

Thanks for the pointers, guys.

Rooster: Those look intriguing, I’ll have to wander over to Lowe’s and pick some up so I can play with them. Are you using them in your layout?

Jim ,

No, but I am using them in my kitchen that I completely remodeled and rewired last year. I know where those connectors are on the mapped circuit and so far so good using 12/2 and 12/3 solid core wire on some heavy circuits. They are pretty slick and can certainly be daisy chained for your application. They can be used with stranded or solid core wire and can be removed fairly easily. It might be a bit more easier than your solder to copper washer idea even though it’s a neat idea. As for the disconnect plugs “No” I have not used them but have looked at them and almost bought them for a stupid idea I had.

You are using 12vDC with LEDs so your draw is very minimal . I personally think those connectors may be the easy the solution you are after or maybe not. Your call, your RR just throwing it out there for you to decide as you asked.

#6

The potted Scotchcast splices are rock solid, impervious to burial. And they’re a PITA, comparatively speaking. But I thought they would be worth the effort for my main power buses.

I sure like the idea of an in-line crimp-on connector, but I’d have questions on its long term survival if you bury it.

BTW, for sprinkler wiring, Rainbird and others sell wire nuts that you pack grease into.

#7

Cliff Jennings said:

I sure like the idea of an in-line crimp-on connector, but I’d have questions on its long term survival if you bury it.

If your gonna bury it I personally would solder it

#8

OK, with what I know at the moment (modulo a Lowe’s trip) I think I’ll stick to my original plan. Anybody else have any other ideas i should consider?

(Rooster: if I have to solder them, I might as well make it easy, and I think the copper washers will be easy (famous last words))

I’ll update this thread as I try things out. I may end up horribly disappointed and looking for alternatives.

Cheers!

#9

For my track wiring, I used the landscape wire and wire nuts. I just spliced together the wires with a wire nut, and then shot the wire nut full of RTV. The railroad was built back in 2002, and the wiring is still working without any detectable failures. For my building lighting, I have buried the same kind of landscape wire under some dirt roads, so I know where it is. When I finally do get buildings that need lights, all I have to do is splice into the wire. Ad for disconnects/plugs, I haven’t worked that part out yet.

#10

Since the LEDS draw a lot less current than the bulbs of old, you do not need anything larger than 20 guage wire.

So, you could just use telephone wire, and it is available in outdoor versions.

I am using this wire to operate LGB EPL drives and has been outdoors for over 10 years on a 30 foot run!!

#11

Dan, that is true. But I went with the larger wire just in case I decide that I need something that draws a few more electrons. I tend to overbuild things, then I tend to not have too many issues with what I built.

#12

Jim,

Those wire splices that Rooster showed from Lowes work really well. The electricians on my projects (Schools and Hospitals) have been using them for years, just make sure they are in a junction box that is weather tight. There are also neoprene gaskets for the lids of the boxes you are showing. Also seal the areas where the wires come out of the box using caulk or other sealant. They also make sealtite connectors for whatever the size of wire you will be using. These are also sold at Lowes or HomeDepot in the electrical isle.

#13

Jim Rowson said:

(Rooster: if I have to solder them, I might as well make it easy, and I think the copper washers will be easy (famous last words))

That was my point Jim …you don’t have to solder them.

Only trying to add my thoughts and experiences as you asked my friend. Keep us posted with your results like you always have! Rooster’s don’t read well but love pictures!

#14

Thanks for all the advice folks! Much appreciated. I’ve been moving rocks around today, but maybe tomorrow I’ll get to this and make some progress. Not enough pictures in this topic!

#15

Outside the box thinking here; how about just bare or thin insulated copper wire strung up on scale poles like the power companies do.

Two wires one side is +ve and the other is -ve then just tap off at each building.

If you make it a ring main feed ie both ends connected to the same point on the power supply then just tap in as required also there should be minimum problems with breaks as well.

For safety consider even a low 5-6V supply that can supply the current as extra buildings are connected.

#16

The issues I see are:

  1. soldering, unprotected solder does not like moisture.

  2. using the ring to add and remove/update circuits. I think if you try to solder a new wire near an existing wire you will have the danger of the existing connection coming apart.

They used to make taps for landscape wire that did not require cutting, and you could fill them with silicon grease…

Scotchlock makes connectors specifically for tapping into a main “feed” https://www.youtube.com/watch?v=2SYfQjIjpd0

I don’t exactly like the idea of taking the feed and cutting it, but basically you take your feed, cut it, and you splice it back together (one connector per wire) and the splice also let’s you tap in your wire to your building, etc.

So, for each of the 2 wires in your main feed, you add a connector that takes the 2 ends of the feed you just cut, and a 3rd hole for the power you are “tapping off”… no soldering, intended for direct burial, etc.

Greg

#17

Call me old fashioned, but I like crimping a spade lug and using a good old strip to make those connections.

Nothing fancy, just tried and true.

#18

I used ring terminals to connect wire to my rails. But I sealed the ring terminals with RTV.

#19

Hey folks thanks for all chiming in here. Lots of stuff to consider.

At this point, I’m thinking that Greg is right about corrosion. The video Greg posted of the 3M Scotlok MGC method of splicing, while it is a terrible review video, illustrates what appears to be a pretty quick, easy, reliable, and not too expensive approach. I’ve purchased a small pile of them to be delivered Friday so I’ll see what they are like when I get them.

I love how everybody is pitching in with their approach. Thanks a bunch!

#20

Oh, and Rooster: I purchased some of those 2 conductor quick connect/disconnect’s. They might be a little bulky but it seems like they can be made to work.

Thanks for that tip!

I’ll post again when I get some hands on experience.