I’m not quite sure if the title above is correct, but I just can’t figure out something better. Basically, when you are doing DIY, then you will play a lot in breadboard or something that’s not in proper or neat condition. Therefore, we used to have this and that connected temporary by patch cable (or whatever you call it). One of them is the power supply cable.

This cable is mostly used to connect a power transformer or something that needs an AC line power directly from the wall outlet. Yes we can always use normal power cable, cut on one of the side, and solder two or three (ground) alligator clips. But what’s missing? The fuse.


I would always highlight safety as priority because when we are playing with high voltage, then there is always a risk of being electrocuted. There is nothing could be worst than being killed by your hobby. Hobby should bring some fun, huh?

This fuse actually not directly related with “being electrocuted”, but more on the safety for your equipment. You will never know when you are connecting your old power transformer – whether they are still working properly or not. By using fuse, it can save your equipment from being burnt or having more catastrophic damage.

There is another way to use a light bulb which I will discuss later in separate article.


So I bought a small fuse holder and solder it to the one of the mains wire. Not a difficult job, but have to make it neat and tidy.


I cover the soldering result with Kapton tape which is a high temperature grade tape, then add few layer of Teflon tape which translated to even safer seal.

The ferrite itself is there from the original power cable. So it’s not there by intention from me. I will let it there as there is no harm by having that ferrite on the cable.


The last thing to do is to solder the alligator clip. Normally I would scratch the alligator clip surface first (on the solder area). This will remove all the coating, so we can solder it easily (sometime the moisture or some coating will prevent the solder to bond perfectly with the surface). After that, we can just simply put the cable on the alligator clip and solder them together. Make sure you get a shiny “well done” surface there. Then we are good to go!

Don’t forget to test the connectivity of the cable first with your DMM or AVO Meter (use continuity check). This just to make sure the fuse is properly installed (check with fuse plugged and unplugged). Also to make sure both main wires are not shorted each other.

After we confirm cable is ok, then it’s time to final real-world check. I use my power transformer and plug the cable into the test to connect the power transformer to the AC main. There you go!