Power Cord made easy

Here is a short how-to on power cord made from 47Laboratory OTA (Open Technology) cable. Of course, all of many times repeated warnings apply. If you decide to make it and use it, you are doing it entirely on your own responsibility. You won’t be able to hold me or anyone else responsible for any eventual damage to your health, life or your equipment. The one to blame is you.

Now, that we’ve done with the scary part, let’s go down on it.

Before you start you should know how many power sources do you need. In this example, since I am making this cable for the forthcoming Shigaraki line (must have everything ready for the occasion), I will need 3 power sources, plus one spare. So, in the example, we will make 4 power sources. Please note that on the photos there is only 3 IEC connectors. Reason for this is that my fourth connector turned out to be faulty and I will need to get it later and I didn't want to make additional delay in posting this.

Next thing you must know before cutting is how long you want this power cord to be. The idea is to have it long enough to reach the wall power outlet. What we want here is to avoid any extension cord and degrading factors brought in by these horrible things called extension cords. So, I need like 3m long power cord.

For that I will need 1 mains connector and 4 IEC connectors. From this you can see that there is no reason to worry about number of wall outlets you have as you wll need only one to connect your complete setup.

Back to the wire: It is easy to calculate how much of the wire you need for the job:

Total length of the wire= 2*number of units*distance to wall outlet
In this example, as I want 4 mains sources and 3.2m length of the finished cord (I gave some extra length), I need 2*4*3.2m=25.6m of cable.

Take the total length of the wire and divide it into double the value of power sources you need. You need two lengths for each power source. So, I want to have 4 sources and I will need 8 lengths of 3.2 meter.

Next step is to remove the insulation from both sides on all wire runs.

When you’ve done with this, line all of the runs together in two groups (you may find it much easier to do this on the floor as you need a big surface for this job). So, I end up with two groups of 4 runs. You can even adjust the directions of the wire to follow the 47Laboratory logo uniformly (the wire itself is not directional until used but I always have 47 on the source and “ry” directed to the end).

Mark one group of wires (meaning half of the total wires) on both ends of all strings in the group with a small point permanent marker (water based is preferred). I deliberately won’t say to use red marker as this could indicate the polarity which, at this point is still irrelevant.

Now, go to the source side of the cable and twist together the ends of each group. Leave the ends on the other side as they are. By this we have prepared the side that goes to the mains power connector.

In the top right corner you can see excess material that we will throw away.

The side that goes to mains outlet is now finished after we've placed these two wrapped ends and screwed them. What I can't tell you is how much force is enough when screwing in the wire... That is something the feel you get with experience. If you screw it too much, you will likely cut off the wire with the screw and if you screw it too little, the wire will fall out...

Having one side completed, we now go to the other, IEC side. The key here is to have everything layed out nicely as here we want to have things done consistenlty, marked string must go on the same side and unmarked one to the other side of every IEC connector.

On this photo you can see that IEC connectors are also not immune from things we won't need. Top line shows excess material that we will throw away.

Here is a trick I use to be sure to have enough "meat" to make a good contact. I bend the bare wire few times...


Once you've screwed in all the contacts, since we won't be using the screws to fix back the connectors, you may use some super glue to fix back the housing (alternative is to use electrician tape but I recommend using super glue, even if it makes a permanent connection).

Please note that, since we are not fixing the insulation to the housing, in order to avoid breakage of the contact and pullout of the wire (which can be even very dangerous on the IEC connector side), never, and I repeat, NEVER pull out connecotrs by wires. Always hold ONLY connector while plugging or unplugging. If you feel uncomfortable with this arrangement, you can keep and use the fixing assembly that I've thrown away.

As you can see, all green marked wires are installed to the left side and all unmarked ones are on the right side.
Why do we want to ensure this consistency?

We want to have LIVE on the side marked with red marker and Neutral on the other (we don't want ground, that is why we haven't used three wires per IEC but two). We want to have it consistent throughout the setup. With a consistent side assignment of marked vs unmarked wires that is exactly what you achieve - you plug in the mains power connector to the wall outlet, check the polarity on one IEC connector and if you have the live on the side marked red, you will have it on all IEC connectors the same, the good way. If polarity checked shows you have it on the other side, just unplug and rotate the mains power connector for 180 degrees and you will have Live and neutral where they should be... on all IEC connectors. Couldn't be easier to achieve the polarity consistency throughout the setup.

The result of our work you can see on the photography on the top of the page. You can see that I've usd also a few plastic locking strips (dunno how they are called in English). You know, the stuff that is used to keep wires together....

Is it good? Well, I hope you will tell me after you have tried it.

Good luck!


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