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How to choose extension cables for a power supply

There is a whole sector within power supplies that is increasingly booming precisely because of another market that is changing, that of PC cases. The manufacturers of power supplies compete hard in all the strata, but very few are those that although competing for price, they offer cables every time of greater length. Therefore, having increased the average size of the chassis by a few centimeters compared to a few years ago, the cables can fall short.

PC and PSU extension cables, a partial solution to the problem

You have to focus on this from the root before getting into the matter, since many may be thinking of buying a PC, a power supply and therefore its assembly and especially its wiring also called cable management.

This is another of the key factors if our chassis is full tower, since the extensors are essential. And it is that the height and the channeling of the cables make the sources remain short in their cables and their length. Manufacturers refuse to increase prices by adding more length to the series cables because, apart from the cost, it has implications related to their impedance and resistance to the passage of current.

This is undoubtedly a problem, but they do not provide solutions as a general rule, such as including serial extenders for the cables, or directly including them sleeved to be able to isolate them and achieve greater length. It is a separate market where they earn a lot of money, so it will not change of course.

Understanding this, now we can see what are the factors that determine the choice of an extension cable for our source and how not to fail in the attempt.

AWG, the main factor to consider


AWG is the acronym for American Wire Gauge and as such it is nothing more than a way of measuring the quality of the cables, it is a way of classifying the thickness of the cables in terms of the wires and the sheets.

Therefore, AWG will be accompanied by a number from 0 to 1000, where curiously the scale does not start at zero, but goes from 1000 to zero and from there it goes up to 40. Normally, the power supplies include this data of their cables as little as it is of quality, but as a rule we are talking about that the industry works from AWG 20 to AWG 16, at least for the moment and in order to see if there are changes by the NVIDIA 12-pin connector.

In any case, fewer cables indicate greater thickness and therefore greater available area, less resistance to copper and more total current withstand, therefore, higher quality.



Another important factor is the plastic connectors. It must be taken into account that in certain more or less extreme scenarios the cables get a lot of temperature, especially if their AWG is high and a lot of energy is being asked of them.

There are cables that are literally temperature limit, where they are very hot to the touch, so the connectors and their material is something to take into account, since after long hours of use small deformations can occur in them, where the most critical point is precisely where the two cables come together.

A bad connector will end up yielding the anchor of the climbed and it may leave some cables loose, especially if the posture of the cable or cables is not good and they are strained. It is not necessary to think that we have to do extreme overclock or much less to get to this, currently high-end CPUs and GPUs manage to consume more than 200 watts and 350 watts without too much problem, so it is a really serious and worrying issue, about all with low and mid-range sources.


It seems a lie, but there are users who force the cables at their ends to insane levels. PSU cables are typically clamped to very high precision and have to be subjected to extreme posture and tension to come out, unless the manufacturer and model are of questionable quality.

This is why extenders have to be really good at this, as bare or out of contact wire, or just partial contact, is a component hazard. Anyone who has assembled hundreds of PCs will have seen this problem, which with the passage of time in these PCs is becoming more and more common.


Let’s not skimp when it comes to choosing length (if possible) except if we are talking about a box with compact dimensions, where any common extension will be useful in this section. As we have said, as a rule the boxes are getting bigger due to the AIO systems.

That extra height or width, which are normally between 3 and 5 cm make the cables barely reach to connect for example the EPS cables, which are the most sacrificed for being as a rule on the top of the motherboards.

Like everything, the extenders have a maximum length to maintain the intensity of the current and not create more electrical resistance, so obviously it is a limiting factor.

Mix different AWG in the extension cables

Power source cable

It is true that there are models of power supplies that do not specify the AWG of their models and cables, but as soon as we search the Internet, we will surely find such information. It is important because there is a very common mistake in most users: mixing cables and extenders with different AWGs.

Although we speak of barely 30 cm of extenders In most cases, opting for a different AWG produces voltage drops, minimal yes, it is true, but these drops due to the different resistors have an influence on the power supply when we talk about nanoseconds of variation such as those produced by GPUs or Current CPUs, where the entire consumption range is dynamic and faster and faster to adjust more and more to energy efficiency needs.

We already saw the problems with the RTX 3000 and sporadic reboots, where they did not even require high graphics load. So the ideal is to use extension cables with the same AWG as the cables of our power supply to avoid surprises.