So, where’s pin 1 on those common 0.156” connectors?

-October 17, 2017

We all like to standardise. But there doesn’t appear to be any pin number system defined for one of the most popular wire-to-board connector sets.

I’ve always followed the marking used on 0.1” Molex KK parts available from local electronic retailers. But is that correct? Furthermore, the 0.156” KK parts are not marked.

Marking the PCB pin header isn’t so important, as the PCB component overlay can clearly indicate pin 1. Marking the crimp housing is important though.

I feel that I have a solution to suit the past and future.

Look at the crimp housing with the wires coming in from the top (observe the dark wire). You will be looking at the housing’s side with the little rectangular openings for the terminal retaining latches.

If pin 1 is leftmost, then call it a KK0.1”-L.

If pin 1 is rightmost, then call it a KK0.1”-R.



If pin 1 is leftmost, then call it a KK0.156”-L.

If pin 1 is rightmost, then call it a KK0.156”-R.


Molex doesn’t appear to have defined a standard pinout.

This KK0.1”-R is defined, based on PC fan use.


However, for the KK0.1”, there does appear to be some commonality, as this connector type was used for the PC’s fan. Add to that other web images and many of the parts that I have purchased (which were marked), suggesting general usage to be KK0.1”-R. I was never able to find any image with a marking on the left.

As for the 0.156” KK housing, I have not been able to find anything. On the original PC, the six-pin power connectors, while technically not KK0.156”, do have the pin-out of a KK0.156”-R.

So was pin 1 meant to be on the righthand side for this too?

If you do happen to have a document defining a standard, please share it with us.

What pin numbering do you use?


Also see:


Peter Baxter is an EE specializing in hardware prototyping and analog instrumentation. 




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