A DCC power enclosure

This is the DCC enclosure that I built and which encloses all my supplies for the SOW layout. These includes the DCS100 Command Station with its transformer, two PM42's, a 24V supply for my DS54 CDU's, A 12V supply for both PM42's, a 12V supply for my modified (Digitoys) BD8's. There is also room for expansion (a booster and its transformer). The enclosure is completed with a number of switches to control individual circuits, indicators and the required fuses for each circuit. In addition, this enclosure is fitted with a fan to dissipate any heat from the DCS100 (and the future Booster). The connection to the outside world (the layout) is made via a couple of terminal boards, at the back.

A few pictures

Front view

Rear view

The component layout (top view)

Detail of the PM42 wiring

Top-front view

Top-rear view

The enclosure

The enclosure I used for this project comes from Radiospares and is item 222-070. This is a cheap enclosure whose dimensions are : 17 x 11 x 5.25 inches. The same type of enclosure should be available in the US for similar prices.

The way this enclosure is made allows for a "base plate" to be installed approx. 1/2" above the bottom of the case. In my case, this "base plate" was made from a sheet of 1/8" aluminum that supported all of the equipment in the enclosure and allowed to run wires under this "base plate".

The placement of each piece of equipment is shown in the above photos. This is what was needed, in my DCC configuration. You may have other constraints, depending on your needs.

However, you'll at least need a DCS100 and probably a couple of PM42's in order to drive your layout. In my case, I needed to have access to the DCS100 front panel, as well as a couple of PM42's and some switches and indictaors on the front panel.

A rectangular hole (4.2x3") was made in the front panel so as to display the front panel of the DCS100. This was done using a nibbler. The DCS100 was attached to the base plate using a strap made of a heavy electrical wire with an eye lug crimped at each end. Two screws tighten this strap (thus the DCS100) to the base plate. Wire ties could be substitued to secure the DCS100 to the base plate.

The picture at right shows the template for PM42 drilling.

This may be the most difficult part when drilling the front panel , especially with the small rectangular holes for the LocoNet connectors.

The upper and lower holes are made to screw the PM4/PM42's to the front panel. The original PM4's had screw terminals used for that. However, it seems that the later PM4's and PM42 are lacking these screw terminals.
It is easy to overcome this problem as the PM42 cards still has the footprint to install these screw terminals. These are Keystone #7690 available through most electronic store (i.e. Digikey under the number 7690K-ND) that should be soldered to the PM42 board.
Once these terminal screws are mounted on the PM42 and all other holes have been drilled on the front panel, according to the template, the PM42 can be attached to the front panel without any problem.

At the right of the front panel are the switches and indicators for the various power supplies in the enlosure. Again, the arrangement for these depends on your particular application. In my case, i have a switch and indicator for each of the power supply in my enclosure and a main switch/indicator.

The back of the enclosure is drilled for the fan (depending of the type of fan you use), its fuse, the main power connector and the terminal boards that go to the ouside world. Here, again, the configuration of the terminal boards depends on your needs (see, below, the "wiring" section).

The wiring

The schematic below shows the AC wiring for this enclosure.

Tha main Power is indicated as 220V AC, as this is what we have here. Of course, for our US/canadian readers a 120V AC power has to be substitued.

The wiring is rather straightforward. The main power goes through a main switch, a main fuse, and power all of the transformers. An indicator displays the main power. The fan is derived from this main power through a fuse. Each transformer is equipped with an ON/OFF switch to insulate the circuit, as needed, and fitted, at its output, with a fuse of the proper value and an indicator.

The above schematic corresponds to my specific needs in term of power supplies. Your mileage may vary and your needs be different but this is a "theoretical" scheme. Some of my supplies may not be needed on your layout, some other supplies may be needed (for lighting, accessories, etc...) but the principle is still valid for any configuration.

The outputs to the Command Station or to the Booster (optional) go directly to these equipments, as well as the 12V supply to the PM42's, while the other power supplies needed on the layout are connected to the terminal boards, at the back of the enclosure.

The figure at left shows the wiring of both PM42's. Those are currently supplied from the DCS100 ("From Booster" input) but some changes may be in order, in case I add a booster to my system.

The wiring of both PM42's suits my current needs (4 protected circuits and 3 auto reverse circuits - themselves protected by one of the PM42 circuits) and may change in the future depending on my needs and the appearance of a booster or not. This is for reference only. Of course, your needs may be different, in term of protected circuits or reverse loops, and it's up to you to define the wiring adapted to your case.

All of the outputs (protected circuits and reverse loops) are connected to the terminal boards at the back of the enclosure, for use on the layout itself.


This shows you what I did for my layout. It is clear that everyone has different needs for its own layout, but this type of enclosure is very versatile and is able to accomodate many different hardware, according to your layout's need.

A last word : for clarity, I made some self-sticking labels for the front and the back of the enclosure. These were made on my computer.

Hope this page gave you some ideas about what I did and what you can do to "package" all your power supply needs for your layout, in a clean and safe enclosure.

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Page created by Jean-Louis Simonet
Last update : 10/28/2006
© 2006, Jean-Louis Simonet