Add an Auto Switch plus a Selector Switch to a PCP in a Box for a NCE Power Pro

by Jim Exler, 08/26/25

Ask Jim a question at: jimXexler@hotmail.com

Here is a series on 3D printing a box for the NCE Power Cab PCP panel and adding an Auto Switch and selector switch.

First, the basic box with the Auto Switch mount and relative to the PCP panel.

Box with Auto_Sw installed (left).
Box with Auto_Sw and PCP installed (right).

The only modification to the NCE components was to cut the traces to the TRACK connector on the PCP to allow the Auto Switch and selector switch to be between the PCP and the output. The picture shows the cut in the traces and wires to feed the Auto Switch soldered in the empty holes just above the left hand cut. Additional wires (red and white) were added to connect from the selector switch to the TRACK connector.
See the notes on the schematic for the sequence of operation.

PCP with modification to add selector switch.

Next is the completed wiring before stuffing it in the box, the rear connectors and the front of the assembly.

Complete wired assembly.
With the switch orientated as shown in the picture, the wiring is:
1-BL    2-WT  3-YL
4-GN   5-RD   6-BK
When the image is blown up, you can see the wiring.

Front

Rear

Another option is to make the cover with a bracket for the Auto Switch. This means that the cover plate holds all the components and wiring so it can be used either with a box (no bracket inside) or as a fascia mount or home brew setup without the box.

Here is a picture of the model from the back side showing the bracket . The function is exactly the same, only the method of mounting the parts is changed.

Cover plate with mount for Auto_Sw

Schematic of box with PCP and Auto_Sw

Optional box for NCE USB adapter

For STL files for 3-D printer, click here.

Note: Some public libraries and universities have 3-D printers for public use.