Published On: Sep 16, 2019
After you have installed a power supply into your case, the next step is to wire the PSU to the correct locations within your desktop computer. In this beginner-friendly walkthrough, we'll explain everything you need to know including how to connect power supply cables to your computer components like the motherboard, CPU, graphics card, SATA drives and any other accessories that require a direct connection from your PSU. We'll also cover basic cable management, answers to common questions about connecting PSU cables, and photos and diagrams to help illustrate certain steps.
If you're building your first PC and perhaps a little intimidated to wiring a power supply (perhaps due to seeing the fair amount of steps to be done below) - don't be! Learning how to connect power supply cables with some basic cable management along the way isn't hard to do. Just take each step below one at a time at your own pace, and you'll be just fine and done in no time. Let's get straight into it.
Note: This power supply cables guide is part of our full Assembling a PC for Beginners tutorial. See that guide for all the before and after steps to building a computer from scratch.
If you have a modular power supply (or semi-modular), which is one that has detachable cables that allows you to conveniently only connect the cables that you need to use for your particular PC build, go ahead and attach the power cables that you'll require for your parts. That's if you haven't already done so when installing your power supply into the case, as in some cases it will be difficult to attach the cables once the PSU has been physically installed.
If you're not sure which cables you'll need for your PC components, don't worry about it and just attach whatever cables you need as you through this guide. But for any PC you'll need to connect the 24 pin motherboard and 8 pin CPU power cables. Set aside any unused cables somewhere safely such as in your PSU box to potentially use in future.
Attach the cables you'll need if you have a modular power supply
We'll cover more tips on cable management in the last step of this power supply cables guide, but before connecting your PSU cables it's good to be aware of some basics so you can try and do a little cable management as you go along with each step (instead of leaving it all until after which could mean having to unplug and reconnect all cables).
As you go connect each power supply cable to the motherboard and other components, you want to thread the PSU cables through any cable holes you have on your case's motherboard tray. The amount and location of these cable management holes will differ from case to case, but here they are on our Cooler Master N200 (the case used for our example build):
The motherboard tray holes for routing cables in the Cooler Master N200 Mini Tower
The aim is to make full use of the gap between the motherboard tray and the rear side panel of your case, as this is where you should be able to hide a good majority of your cables in most modern cases. Just make sure when routing cables in this back area of your case that you will be able to easily replace the case's side panel later on without damaging your cables (in other words, make sure the side panel doesn't squish cables when you close up your case).
Besides utilizing the back of the case to hide cables (as in, the back when looking at your case side-on, ie behind the motherboard), you can use other areas to hide excess cables such as attaching them to the bottom of the case, within a PSU shroud if your case has one (ours doesn't), or even within an unused drive bay. Every case is slightly different. We'll revisit some cable management tips later, but for now let's move on.
Before you physically connect the power supply cables, just a quick heads-up. Plugging in power supply cables will require a firm push to make sure they're in all the way properly (to avoid having an unstable system thanks to loose power connections). You might even have to push quite hard to get that 24 pin motherboard power connector in.
My point? Before plugging in any PSU cable, be sure you're inserting it the right way around (there's only one correct way) by matching the pin patterns on the underside of the PSU connection with the pin patterns on the motherboard (or on any other components you're plugging the PSU into such as a graphics card). You don't want to firmly push a power cable the wrong way in and risk bending or breaking the pins.
What if a Power Supply Cable Doesn't Reach?
Also, if during the steps to connecting power supply cables below you find that a certain power cable doesn't reach to where you need to plug it in (perhaps you're building in a large case and your PSU is a fair distance from the motherboard), or in the rare chance your PSU is missing a certain connector that you require, you may be able to buy an extension and/or adapter.
Power Supply to Motherboard Diagram
Every PSU installation will require 2 direct connections to your motherboard. One for the main motherboard power, and one for the CPU power. The locations where you plug these in on a motherboard will generally be around the same area from board to board. Here's where you connect the power supply cables to the motherboard for our example build:
Where to plug the 8 pin CPU cable (YELLOW) and 24 pin motherboard cable (RED)
Now you know where to connect the power supply cables to the motherboard, let's go ahead and do that, starting with the big 24 pin main motherboard power cable. On modern power supplies this will either be a straight 24 pin connector, or a 20+4 pin connector. Some motherboards only require a 20 pin motherboard power connection, in which case you would only plug in the 20 pins (and not plug in the 4 pins). But modern motherboards will require a 24 pin power connection.
See the motherboard diagram above for what the 24 pin connector looks like on a motherboard, and go ahead and plug it in. If you're having trouble finding where to connect the 24 pin (20+4) pin connector, see your motherboard manual. In our MSI manual it's labelled as 'ATX_PWR1' so it should be something similar for yours, and it should also have it written in small writing on the actual motherboard next to the connection.
Line up the pins the right way around, and plug in the 24 or 20+4 pin connector nice and securely. You might need to give it a firm push in to make sure it's inserted all the way in to avoid it potentially coming loose in future. Hold your motherboard if you need to while firmly pushing it in.
The wide 24 pin cable plugs into the matching 24 pins on the motherboard
The 8 pin power supply cable needs to connect to the motherboard too, and is used to provide your CPU with power. It will be in a 4+4 pin arrangement, so look for the same 4+4 pin connection on your motherboard which should be near the CPU socket. See the motherboard diagram from earlier to see what it looks like. In our motherboard manual it's labelled as "CPU_PWR1", so check your own manual for something similar if you get stuck.
Most modern motherboards will require the full 8 pins to be plugged in, but some may need just 4 in which case you can just plug in either of the two 4 pin headers. Line up the pins carefully, hold the motherboard for better control, and push the cable nice and firmly into place.
The 4+4 pin power connector plugs into the motherboard
Most modern graphics cards these days will require a direct power connection from the power supply, however some lower-powered GPUs like the NVidia GTX 1050 Ti don't require dedicated power (and receive all required power directly from the PCIe slot on the motherboard).
If your GPU does need a direct power connection (it will say so in the specs, or just look for the pin connectors like the ones pictured below), it will either be a 6 or 8 pin connector, or dual 6 and/or 8 pin connections for more power-hungry GPUs. For example, the MSI GeForce RTX 2070 Super Ventus OC requires both a 6 pin and a 8 pin power connector:
Any decent modern power supply will come with two PCIe power connector cables (at least), which will come in the form of 6+2 pin connectors so you can connect to either 8 or 6 pin connections on a GPU. Go ahead and plug in any PCIe power cables that you need to for your particular video card.
The 6+2 pin power supply cable which connects to a video card
In the rare case your power supply doesn't have enough PCIe power cables for your graphics card, you could use a Molex to PCI-E adapter (some GPUs come with them), although this is only recommended as a last resort as it's not ideal.
Not to be confused with the SATA data transfer cables that should have come with your motherboard (and which you plug from the motherboard to the hard drive), these SATA connectors power your storage drives (SATA SSDs or HDDs), optical drives, and some accessories like certain CPU liquid coolers.
Connect the SATA power cables into your SATA drives or accessories
If you have a ton of SATA drives/accessories and your PSU doesn't have enough SATA power cables to connect them all, you can use the Molex connectors on your power supply using a Molex to SATA adapter. Go ahead and plug your power supply SATA cables into any HDD/s, SSD/s, or optical drive/s that you have in your desktop.
Plug the SATA power cable/s into any SSD, HDD, or other SATA parts
Note that if you have an m.2 SSD, these storage drives do not require power cables (or data cables) for that matter, so this step does not apply to them. These super-thin SSDs slot directly into the motherboard and are powered solely by the motherboard.
Molex connectors have been almost completely replaced by SATA connectors, however some power supplies still have them and you may still need to use them for accessories like some CPU liquid coolers or case fans. They are the 4 pin connectors that look like this: (and might be labelled as "peripheral" cables in your PSU specs)
Molex power connectors may be needed for certain accessories
For example, for our example PC build used in our complete PC building tutorial, because we can't plug in our case fans directly into our motherboard due to only having the one fan header on the board, we'll connect the case fans into the Molex connectors of our PSU.
Go ahead and connect your case fans if this applies to you, although ideally you want to plug case fans into the motherboard fan headers. The downside of having case fans connected to your PSU directly is that you have no control over them and they'll always run at 100%.
Being able to plug fans directly into the motherboard (if your board supports it) allows you to use software to control how fast the fans spin. You probably don't need to worry about this, but it's just something to keep in mind. Sometimes fans can be louder than you like and you'll want to adjust their settings.
If you don't need Molex connectors, and you're using a modular PSU, simply keep them in your PSU packaging, otherwise you'll have to tuck them into your case somewhere. Another thing I'll say about Molex connectors is that they sometimes need a real, REAL firm push to connect them properly, so don't be afraid of using a little force with these guys.
After connecting the cables you need, you'll want to tuck away any unused cables of a non-modular PSU neatly within your case somewhere
As we explained earlier in this guide, while connecting the power supply cables to your PC you want to be threading the cables through the holes in your case to keep things nice and neat. Once you've connected all the cables, you want to finish off with some extra tidying up of cables wherever you can.
Why Do Cable Management?
This is good to do even if you don't have a see-through case that shows off your internal components, as cable management isn't just for aesthetics but for practicality and extending the life of your computer (by maximizing airflow, limiting dust build-up, and avoiding loose cables potentially damaging other parts).
The amount of cable management you do after you've connected your system together will depend on your build, and how much you care for your new system. Truth is, some first-time builders will just rush over it (or not do it at all), and there's nobody forcing you to do cable management. A messy build isn't the end of the world, but we do recommend spending a little time now to clean things up as best you can. It doesn't have to take you long, and a simple 30 mins to an hour of tidying up cables could be well worth it for your new system in the long-run.
Non-Modular PSU Cable Management
If you have a modular PSU, cable management will be easier as you have less cables to manage neatly. If you have a non-modular PSU, such as the one we've installed for our example build in this tutorial, as well as threading any cables you connect through the back of the case first you'll want to then tuck away the cables you didn't connect (the ones still attached to the PSU) nice and neatly within the case somewhere such as under the hard drive cage/caddy which is what we'll do in our build.
Avoid Cable Clumps of Doom
Besides cable management 101 we explained earlier in this guide, which is primarily about threading cables through any available holes in your case, you also want to use cable/twist ties to bundle any stray cables (or groups of cables) together into the same direction and position them against the side panel. You want to avoid having any big bulges/clumps of cables within your system. Some cases go the extra mile here and have quick release cable ties and small lugs built-in to the back of the case you can conveniently attach cables to.
Just Do Your Best
As you're doing any cable management, keep airflow in mind and try not to cover your coolers or case fans with cables if possible. If your case doesn't have too many options for cable management, don't worry too much, but do your best to make do with what you have.
Don't Forget the PSU Main Power Cable + Power Switch
That wraps our guide to connecting power supply cables to your PC components as a beginner. Hope this detailed tutorial helped, and that you enjoyed reading as much as I did creating it. Oh, and by the way, we didn't mention plugging in the PSU to a wall socket (mains power), as that should only be done once you're ready to boot-up your PC build for the first time which we cover in the next step of building a PC from scratch (see below). When you do plug the PSU into the wall, don't forget to also flick the On switch on the back of the PSU as well!