Cam’s electrical wiring

“Dear Al,

Though I would post the next instalment on lighting the layout. This is a pretty extensive area normally so I will try and keep it concise if I can.

After the points were in place I decided that I wanted to light the layout. A previous post, I think from Arnie, pointed me in the right direction with regards to how to control the lighting. I wanted to have a lighting control dial that I could turn to different times of the day with each position of the dial turning on a different combination of lights. This is how I set it up.

Positioning the lights.
I fixed the lights in place from under the layout so I could take them out and change them without ripping up any of the buildings to do so. I came up with this cheap fixing method that has worked pretty well. I first drilled holes for each light before the buildings were fixed in place. I then made a wire bracket from fencing wire (coat hanger wire would also be fine) that would hold the light in place but be fixed from under the table. The bellow diagram and photo better describes this arrangement.


Very smart! A big thank you to Cam.

And while you’re here, check out the latest ebay cheat sheet.



31 Responses to Cam’s electrical wiring

  1. Thanks Cam, very nice. Would you mind suggesting which diode you use. Only some of the numbers are visible in the photo. I think it must be a 1N962_???

  2. Novel ideas. Thanks.

    Please explain the wiring pictures [last and 3rd from last].
    Are those dimmers for the LED’s?

  3. A great idea for mounting the lights under the layout. Thank-you. Not only will I use this method on the next lights but will begin to re-install the ones I put in already. This method also solved one of my problems with placing a light on top of the inside of a building without actually mounting the light to the structure.
    I’ll just use a longer piece of hanger to get the light where I want it.

  4. Thanks for the wiring tips………..this will help me when I set up my N gauge model railroad…… Ron

  5. Spectacular diagram and a wonderful method for adding light without removing building. Definitely going into my reference file. thanks so much.

  6. What are the white plastic wiring gizmos that look like plastic terminal blocks?

  7. Thanks cam, I am going redo some of my wiring.

  8. cam great idea with the lights. thanks for your idea.


  10. Oh, yes it does

  11. For Donnell’s info (or anyone else for that matter) typical diodes for this application would be 1N4001, 1N4004.

  12. That’s a fantastic idea, I used hot glue inside the buildings I shall now change some of them as you say its better and more efficient, what are the white boxes.

  13. RESISTORS – DON’T FORGET RESISTORS MUST ALSO BE USED WITH LEDs if you’re using a 12volt supply then EACH LED will require a resistor, otherwise the LED will be destryed.
    For a 12volt supply you should include a 560ohm / 820ohm or 1000(1k)ohm resistor in series with one of the leads.

  14. love the mounting system never would have thought of that

  15. I love the idea Cam, I need to get started before I get too far behind…

  16. Thanks for sharing a great idea! The snaps that followed the diagrams were tempting – can you explain them? (Use of LED’s, the wiring in the black box labelled “…morning midday afternoon…” and how the under-table dimmers are involved in the system?)

  17. Thank you Cam for your lighting article. I was just thinking about layout lighting the other day, and how best to wire up the layout so as to turn on certain lights before others. (Shades of turn-out relay/switch diode matrix setups). As for the type of diodes to use; If using LEDs, 1N4001 diodes that you can get at Radio Shack, Dick Smiths, (if they are still around), or your favorite electronic supply shop should work without problems. Be mindful of diode polarity. And your way of mounting the LEDs is marvelous. Why couldn’t I think of it? Just remember to insulate the LED wires so that you don’t have shorts.

    The suggestion that I offer is to wire the diodes on a pre-drilled phenolic board, all orientated in the same direction but in groups. For easier trouble shooting and servicing, label the groups for their particular area of lighting. (Like for street lamps, store fronts, houses and so forth.) Instead of using a rotary switch, using a bank of lever or slide switches might be better. That way you could turn on or off sets of lights in a different order as you see fit, for different times of day or night..

  18. Cam I was wondering why did you use a diode rather than a resistor?
    The wiring idea is a good one and will be redoing my lighting on my new layout.
    Thanks for the info.

  19. Hi everyone.You seen some of my thing’s i build,like the tower and many other’s and even how to hookup led’s in your engine instead of factory balbs,anyways i build alot of this’s but the wireing scare’s me.Ive gone threw so far a few led’s and melted a few wires.This is going to help.Thanks for the info.Going to give it a try

  20. Great way to mount lights. To reduce the physical size of the cable groups you can use “wire wrap” cable since the diodes draw very little current.
    Cheers Ralph.

  21. Nice idea, good photo’s would be better if you described what was going on, you know captions.

  22. Dear All,

    Appologies if the last post was seemed to be missing some information about the setup. The old cut and paste gets the better of us all at times. Hope this helps to fill in the gaps.

    The Lights
    I have used 12volt LED lights throughout to avoid having to use resistors. I have found that the “warm” coloured LED’s look much better when lit up. The regular LED lights look very blue when you light them up so are better for replicating areas where you would find flourescent lights like sheds and factories. The street lights are grain of wheat type bulbs which draw a bit more current but look the part.

    Controlling the Lights
    To control the lights I used a “diode matrix” and a rotary switch. There are a lot of posts on diode matrixes. They are often used for throwing multiple points at once. I have fond some of the circuit diagrams difficult to follow so I have draw my own version to explain how it works. (apologies for the spelling mistake in diagram)

    The purpose of the diodes is to prevent the current from finding its way to lights you don’t want it to. The diodes will only pass current in one direction. My lighting runs from a 12v 4 amp power supply. For the switch I used a “1 pole 12 position rotary switch” and “3A 100v rectifier diodes” all can be bought on Ebay quite cheaply. You can extend the above diagram as much as you like as long as you don’t draw more amps than you have. If you stick to LED lighting you will be fine.

    The “diode matrix” I made using a “bread board” from the local electronics shop. The bread board is good because you simply push each diode into place and cut down on the amount of soldering. The one I got was too small and subsequently messy. I would get a bigger one next time.

    I made the swith controler to match the mimic panel described in the earlier post. I did include a combination that turns all the lights on at once to help me test them.

    I am very happy with this arrangement because I can add lights to the layout over time without needing to upgrade the switch panel or the diode matrix itself.

    Dimming Lights
    I have found that sometimes the LED lights are too bright for the building they are in and make the whole thing glow like a cheap Christmas tree light. I looked at a variety of ways to dim the lights by painting them, covering them with bits of paper etc. The best way I found is probably the most obvious. Hook them up to a dimmer. You can not dim LED’s with a variable resistor or they will burn out. Fortunately you can get LED dimmers. The ones I have used are “12v 8A LED light dimmers” also found on Ebay. I mounted mine under the table as once they are set you don’t really need to adjust them. They attached to the lighting circuit between the “diode matrix” and the lights themselves. You can run multiple lights off one dimmer.

    The whole lot works pretty well. I am still adding lights to the layout. When they are all in I will do the video as promised.



  23. Cam;
    Very nice wireing! Could you relay more information on the LED Dimmers?

  24. Cameron:

    You have a flair for hand lettering. Are you an architect or draftsman?

  25. Al: I have found most people throw away their Christmas lights when the string stops working. Testing usually proves only one bulb is bad. These bulbs strings can be cut up with pigtails about 3-4 inches for each bulb. When you wire these in SERIES with 5-6 in each set they work perfect for house lighting. Not real bright and yet bright enough to make your night scene very realistic. Since they were probably headed for the trash can they are totally free. Also they can be connected directly across your controller on fixed DC or AC. What could be better? For the DCC people connect to your 12-17 volt power supply.

  26. I am reminded of an old model railroading axiom…8 wires and 4 relays is better that 4 wires and 2 relays. My layout is slowly progressing. I am using lots of the tips seen here.

  27. I take tissue paper and place it inside of the windows, to hide the bulbs. If the lights are making the building glow tinfoil works great and you can also make some of the windows dark.

  28. If you are a grain of wheat bulb user an old transfomer makes a good dimmer which also allows the bulbs last longer.

  29. pretty kewl will have to try it, but why would one need street lights at 12 pm the sun is still shining

  30. Hi Cam,
    You didn’t specify the voltage on your power supply. That is sort of
    important unless you like to burn those LED’s out. And you don’t really
    need a diode in series. LEDs will work from AC, too because they ARE
    diodes. Just need a dropping resistor .

  31. I read a lot of the tips here on line I have really got a lot of HELP from everyone, I`m new at this Just building a N scale layout since I retired. I have some questions for Cam or anyone who can help. I need more info on the electrical work. Which way does the diode go in the circuit? Do you need a diode for every light or 1 for the entire setup. what value are the resistors? I have a 12 volt power supply I checked the output and its 14volts is this ok? If I want to lower it what resistor could I put in line to drop it to 12volts? I have only a little electrical past as you can tell I need help in real basic form. Thanks for all you who help spread the good tips you have learned. Desert Rat RR

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