Cables in Power Supplies: Thickness and Connectors

There are many cables that a power supply has as a general rule: the 20 + 4-pin ATX connector, the 4 + 4-pin EPS, the SATA, the PCI-Express, the MOLEX and even in many models there are also cables Floppy. Given that after all in a PC everything is connected to the motherboard, we can think that why is not all the PC’s energy centralized in it, right? Let’s see it.

The layout of the power supply cables

Without going to complicate our lives with exact parameters, you should know that each cable has a section (or diameter), and depending on this it is capable of admitting one voltage or another of energy. Thus, generally in PC cables with category 16 AWG are used (whose diameter is 1.29 mm with 1.31 mm² of section), since no more is needed to transmit the 12V at which a PC generally works as a maximum ( much less in other components).

There are some components that need their own cable simply because of how the computers are physically designed . For example, even if you connect a hard drive or SSD to the motherboard and unless it is M.2 and is connected to its dedicated socket, you will need to give it extra power with a SATA cable from the power supply, since the device is ” separated “from the plate. The same happens with graphics cards that have additional PCI-Express power connectors, because of their physical location they require dedicated cables.

Thus, the first reason for the sources to use so many thin cables is the compatibility with the different components that a PC uses, something that in turn gives it greater versatility because, as you know, each PC is a world and we can design its hardware with the same components that we want (as long as they are compatible with each other, of course).

The second reason we could say is by tradition, and is that the AT standard and later the ATX already used 16 AWG cables, which has not been changed because they have been manufactured that way since then. A change in the gauge of the cables could mean having to change many production lines, notably raising the cost of manufacture (which is now quite cheap, all said).

Thus, it has always been easier for manufacturers to add more and more cables as consumer needs have changed. Some, in fact, argue that a change in the gauge of the cables would not imply a direct benefit, and yet would force many changes to be made at the level of the entire industry, since it would no longer be only to change the cables of the power supplies , but also connectors for hard drives, graphics cards, motherboards, etc. This is basically the main reason why so many thin cables are used instead of just one thicker one.

And what will happen in the future?

Nor can we rule out a future in which all the PC’s power is managed directly from the motherboard, and that with a single power supply cable we have enough to service the entire system. In fact, this is how some laptops and AIO computers that have an integrated power supply are designed, but this is because they have their own internal design and yet they still have their own internal connections to power each component.

In any case, taking this to desktop PCs that are mostly DIY (since even in OEMs we can always change and add components) this would imply enormous changes in the entire hardware industry, and until the benefits of doing so does not justify the cost and the implementation of the new specifications, you can count on that things will not change.

Appendix: AWG conductor equivalences

For reference, these are the wire sizes and diameters according to their AWG category.