Terminal Blocks for Dupont Connectors 2.54 Pitch

When prototyping electronic creations it's easy to use pre-made modules from AliExpress or other suppliers and to wire them to the microcontroller using 30AWG with Dupont connectors to slide over the pins on the microprocessors and modules. 

But what do you do when you only have one GND or 5V source that needs to be distributed to multiple components or you want to have multiple devices on an I2C or 1 Wire bus.  To breaking out that wiring I use to solder together as many wires as required from the source to connect them all up.  Then you had to get all the lengths correct first time ... it was bulky and painful.

I thought someone must have created a terminal block using 2.54 pin headers and then insulated them ... but I couldn't find anything ... so after looking so I made my own.

I start by using a wire wrap tool to wrap a strand of 30 AWG copper that I have pulled from a short piece of 20 AWG multi-strand wire.  Then run the wire alternately back and forward ... a few times around the end pin and back and then a few times around the pin I started on.  This works ... but to make sure I got a really good connection I then soldered the pins together using the copper wire as a bridge for the solder.  I use lots of rosin flux.  Place the pins in an old breadboard you don't care about for soldering ... wait 10 seconds between each pin so as not to melt the breadboard of plastic holding together the pins headers.

Then clean it in alcohol and push it into the 3D printed insulation block for that pin size.  I super glue mine in just to be sure it can't come off.  But it's a tight press fit anyway.  I use ABS and a 0.4mm nozzle on a Bambu X1C with a 5mm brim.  

If you are prototyping use large blocks and then the pin covers to cover unused pins, so you can add new parts.  But if it's post prototype just make up the exact block sizes you need .. 

These are obviously great for Ground and VCC but also great for I2C and One Wire as you add items just replace with bigger blocks.

I have supplied models for terminal blocks from 2-9 pins and pin covers from 1-6 pins.  Also included are the original FreeCAD files ... just change the pin value in the pinset variable set if you need longer terminal blocks.

I crimp my own DuPont cables and use the silicone 28 AWG wire that's very flexible and fire proof.   I try not to use the male connectors as they are easy to short if they come loose.

If you find this useful share a photo of where you used it in the comments.

UPDATE 5th April 2026.  
I now don't solder them as I have mastered just connecting with the wire wrap ... I wrap every single post with multiple interconnects woven backwards and forwards.   Makes a very nice connection.  The secret is to lift the wire wrap tool slightly (say 1mm) when you feel the wire tightening and it would break ... this makes a tiny amount of slack and it doesn't break and keeps winding.   Once the wire is out of the slot on the wire wrap tool you don't have to lift anymore, just keep turning to finish with a very tight wrap.

Also I am now using mouse ears rather than brims to keep them stuck to the plate when I build them from ABS / ASA.

UPDATE 9th April 2026
I had one loose connection on one pin even though it was wrapped.  So I have reverted to soldering them again.  But now I just make a very brief solder joint, just enough to attach the wire to the pin ... I don't bother filling in the gaps between pins.  That has worked well on 2 prototypes since.