Assistance Needed: Power Supply to +12v DC

[Luc]

Dear Overclockers,

I hope this message finds you well and thriving in the world of tech wizardry!

I've recently embarked on a mission to power my Netgear GS108Tv3 switch using my Corsair AX860i power supply, and I find myself in need of some guidance.

Here's the scoop: I'm looking to tap into the AX860i's +12V output, and I suspect the CPU input (on Corsair PSU) might be the golden ticket. My trusty Netgear switch has an input of +12V 1A DC male power, and I believe this Corsair powerhouse can deliver the spark it needs.

Now, my quest for the perfect connection has led me to ponder two options:

1. Ready-Made Magic: Is there an enchanted cable that converts goes from Molex pin to +12v DC male?

2. DIY Power Symphony: Alternatively, I'm not afraid to embark on a cable crafting adventure! Any product recommendations I'm all ears (and wires)!

Your expertise is my compass, any insights, recommendations, and any pearls of wisdom you might have are greatly appreciated.

Link to a little visual representation I've made on how I plan to wire everything together, so far: https://postimg.cc/vgMQjJDT

 

[5abr3]

Possibly a dumb question/clarification but is this power supply going to be in a computer (and running that too) or is this going to be freestanding to run the switch?

I did something similar a long time ago for a router when it's power brick decided to be just a brick... if this is going to be purely running the network switch you will need to also short out the start pins to tell the PSU to start delivering power so you would have some options:
1) Use the 12V and GND from the 24 pin ATX supply and only have one connector to handle
2) Stick to your original plan of using a CPU connector and get a PSU test connector to handle telling the PSU to start (you may even already have this available)

When I did it I just cut the power lead off the brick and attached it to a molex power extender I had lying around spare with a soldering iron via a fuse as that was before I had a modular supply.

In terms of pre done leads you are unlikely to find anything, usually tend to be the molex or SATA connectors that you find barrel jack's on as adapters and you need to know what spec of barrel jack the device had originally and be sufficiently trusting of the typically random vendor selling it.

 

[Luc]

Hey 5abr3,
Thanks for getting back to me, such useful info!

Yes the PSU will be running a PC/TrueNAS server (i7 5960x, 32GB DDR4, Asus x99-E WS, GTX 970 + 12x HHDs), I wonder if connected to a computer would I still need a PSU test connector?

''Molex power extender'' sounds like a great idea, but not sure it will fit into my Corsair ax860i PSU: https://www.tweaktown.com/image.php...platinum_digital_power_supply_review_full.jpg

Originally I was planning on using a 2-pin ''CPU'' connector like such: https://www.moddiy.com/products/PSU-Modular-Power-Supply-2-Pin-Connector-with-Pins-Black.html
*as I would only be connecting + and - wires, so using a 6/8 pin PCIe/CPU connector seemed like overkill (+ all of the extra wires I wouldn't know what to do with haha)

My current pieces of the puzzle:
1. Corsair PSU with PCIe / CPU (the 24pin ATX I'd need for my motherboard)
2. Original 12v DC Male Barrel Jack (so it should be solid)
3. Mini Inline Fuse 1A (should I look for 2A?)

Looking for:
1. 2-pin PCIe connector
2. Insulated Wire, 10, 15 or 20 AWG?

 

[5abr3]

Hey 5abr3,
Thanks for getting back to me, such useful info!

Yes the PSU will be running a PC/TrueNAS server (i7 5960x, 32GB DDR4, Asus x99-E WS, GTX 970 + 12x HHDs), I wonder if connected to a computer would I still need a PSU test connector?

OK, so in this circumstance the power status for the server will also directly determine the Ethernet switch power (server and switch both on or both off) so the test connector wouldn't be viable as the server motherboard will assume that role. Whether that's OK or not for you will depend if its a 24/7 on server and what else is attached to the switch and what their power and data loadings look like. E.g. if you have camera's attached to the server and they feed data only to the server then all on/off is probably fine but if one is just on the switch because that's where you had a free port and is something else then turning the server off may be inconvenient.

''Molex power extender'' sounds like a great idea, but not sure it will fit into my Corsair ax860i PSU: https://www.tweaktown.com/image.php...platinum_digital_power_supply_review_full.jpg

My supply wasn't modular, was just as an example in case an alternative connection plan is needed.

Originally I was planning on using a 2-pin ''CPU'' connector like such: https://www.moddiy.com/products/PSU-Modular-Power-Supply-2-Pin-Connector-with-Pins-Black.html
*as I would only be connecting + and - wires, so using a 6/8 pin PCIe/CPU connector seemed like overkill (+ all of the extra wires I wouldn't know what to do with haha)

Before trying to nail it down to a specific connector it would ve more helpful to understand what you are already using on the PSU for the server. I would suggest the simlplest way to do this is to take an image of the power supply connectors and drop labels over the connectors you are already using so we can see what is free for use.

My current pieces of the puzzle:
1. Corsair PSU with PCIe / CPU (the 24pin ATX I'd need for my motherboard)
2. Original 12v DC Male Barrel Jack (so it should be solid)
3. Mini Inline Fuse 1A (should I look for 2A?)

Looking for:
1. 2-pin PCIe connector
2. Insulated Wire, 10, 15 or 20 AWG?

Before we can answer the Fuse and wire size question properly: are you planning to use the PoE functionality or do you want to just set it up as a 1.5A supply up front just in case?

Your current switch supply I think is 1.5A so a 1A fuse may not be sized correctly to avoid nuisance blows, but there are 1.5A fuses available from different fuse families.

Have you also considered how you plan to get the wires out of the case yet?

Edit: clarified a little around the 1A vs 1.5A availability

 

[Luc]

OK, so in this circumstance the power status for the server will also directly determine the Ethernet switch power (server and switch both on or both off) so the test connector wouldn't be viable as the server motherboard will assume that role. Whether that's OK or not for you will depend if its a 24/7 on server and what else is attached to the switch and what their power and data loadings look like. E.g. if you have camera's attached to the server and they feed data only to the server then all on/off is probably fine but if one is just on the switch because that's where you had a free port and is something else then turning the server off may be inconvenient.


My supply wasn't modular, was just as an example in case an alternative connection plan is needed.


Before trying to nail it down to a specific connector it would ve more helpful to understand what you are already using on the PSU for the server. I would suggest the simlplest way to do this is to take an image of the power supply connectors and drop labels over the connectors you are already using so we can see what is free for use.



Before we can answer the Fuse and wire size question properly: are you planning to use the PoE functionality or do you want to just set it up as a 1.5A supply up front just in case?

Your current switch supply I think is 1.5A so a 1A fuse may not be sized correctly to avoid nuisance blows, but there are 1.5A fuses available from different fuse families.

Have you also considered how you plan to get the wires out of the case yet?

Edit: clarified a little around the 1A vs 1.5A availability

Hey 5abr3,

Excuse my incorrect terms, as this is not my field of specialty, however, I'm eager to learn. I will try to answer your questions to the best of my ability.

The server I am building will be a home/TrueNAS server acting as a website host, so will be turned on 24/7 (at least thats the plan).

Here is a picture of my PSU (the red is in use), leaving the : https://postimg.cc/WdK0VxNb

At the moment I am not using the PoE functionality and I was not planning on, however somewhere down the line I might, so probably best I prepare for that (happy to buy a higher AWG wire, if thats whats needed).

As for my Switch supply, the manufacturr states its a 1A supply, and the same is labeled on the power supply that comes with the switch +12v 1A
PAGE 14: https://www.downloads.netgear.com/files/GDC/GS108Tv3/GS108Tv3_GS110TPv3_GS110TPP_HIG_EN.pdf

 

[5abr3]

Hey 5abr3,

Excuse my incorrect terms, as this is not my field of specialty, however, I'm eager to learn. I will try to answer your questions to the best of my ability.

No problem, especially if you'll excuse the terrible typing (I blame the phone...)

The server I am building will be a home/TrueNAS server acting as a website host, so will be turned on 24/7 (at least thats the plan).

Here is a picture of my PSU (the red is in use), leaving the : https://postimg.cc/WdK0VxNb

At the moment I am not using the PoE functionality and I was not planning on, however somewhere down the line I might, so probably best I prepare for that (happy to buy a higher AWG wire, if thats whats needed).

As for my Switch supply, the manufacturr states its a 1A supply, and the same is labeled on the power supply that comes with the switch +12v 1A
PAGE 14: https://www.downloads.netgear.com/files/GDC/GS108Tv3/GS108Tv3_GS110TPv3_GS110TPP_HIG_EN.pdf

I agree preparing for future use is the sensible move and thanks for clarifying the supply values, let's stick to what your supply is rated for.

On the connector side of things, the 2 way connector you found will not connect to the PSU because the latch will probably collide with the metal on an 8 way header (you can see the ski ramp on your PSU sits between 2 banks of cavities and it looks like the clip on the photo you linked to isn't half width) as well as more critically the housing cavity key coding not lining up with the cavities.

I would suggest you get an 8 way housing as the the header on the PSU, you don't have to populate all the cavities after all...

If you are planning to build the lead assembly from scratch anyway that shouldn't be anything other than a few pennies more for a slightly bigger bit of plastic (would suggest using central cavities too mechanically when we get to that).

On the wire size and fusing front: 1A load so use a 1A fuse - I would caution against over sizing the fuse when you can get a 1:1 rating match. The fuse is there to protect the wire, not the device so you want it to fail when you get outside your expected parameters. The fuse will not instantly blow at anything over their rating either, they will take excursions beyond their rating (the bigger the excursion the quicker it goes and mini-fuses are fast blow type). Wire size wise, without the insulation spec I am guessing a little, but if it's PVC with no weird plasticizers then 20AWG (0.5mm^2 -ish) should be fine for a 1A load (105C melting point). Personally I would however go for the largest wire size I can get (so lower AWG number if you aren't familiar with that system) & that the terminal can take to minimise the potential for volt drop causing an issue on the Ethernet switch; and I dont know how far you need the lead to reach so that should avoid that problem

I'll pull the connector data up in a bit and see what those connectors are officially capable of (and if there's a decent terminal de-blocking instruction in case you want to use a pre built power lead)

 

[5abr3]

Managed to get time to fight with the Molex website over lunch: the connector series will officially take from 24 AWG (~0.25mm^2 with insulation diameter from 1.22mm) to 16 AWG (~1.3mm^2 insulation diameter to 3.15mm).

The deblocking tool appears to be very specific and expensive for a 1 off job so if you are building your own, get some spare housings and terminals! If you are using a pre-made lead then you could just cut and cap off the unused 6 wires using individual heat shrink sleeves on the cut ends.

Also a reminder that a fuse should go as close to the supply as you can get.

If you need help with Molex part numbers let me know.

Also you still need to consider how you are going to route the wire out of the server case without potentially damaging the wire... possibly through a grommet on a PCI bracket if you have a position unused.

 

[Luc]

5abr3 my amigo, thank you so much for all of the above, you've cleared up so many questions!

As for the connector you are 100% correct the 2-pin would not fit (intially I figured I'd just cut away the clip haha), but much better to go with a full 8pin CPU/PCIe connector and just use 2-pins. I've bought this one: https://www.aliexpress.us/item/2251....0.0.6b9238daKSLqty&mp=1&gatewayAdapt=glo2usa

Copy on the fuse (1A it is!), will also make sure to place it close to my PSU. May I ask the reason behind placing it closer to the PSU rather then farther away. Also I should add that the distance between the PSU and the switch is 20-30cm or 8-12 inch, so not long at all.

To give you a better understanding of my project, i've decided to build the whole server inside a vintage 1960s military crate (I just cant stand the plastic PC/server cases haha), so the whole project will be DIY and the route cable management you've asked about will all be done inside the case. The only cable inputs that will be connected to the outside of the case are the 220v power cable (for Corsair PSU), all the swtich ethernet inputs and a individual RJ45 input that will be going straight to the switch and motherboard. Very unconventional I know, it's just how I like to roll haha

Copy on the AWG 24 AWG (~0.25mm^2 with insulation diameter from 1.22mm) to 16 AWG (~1.3mm^2 insulation diameter to 3.15mm). Will probably go with 18 or 20 AWG, hit middle ground
*would you be able to share the link to the Molex website you got this info from

Again thank you for all your help, much appreciated

 

[Luc]

PS when choosing an inline wire fuse would you recommend a standard size fuse or a small/micro size?

 

[5abr3]

5abr3 my amigo, thank you so much for all of the above, you've cleared up so many questions!

As for the connector you are 100% correct the 2-pin would not fit (intially I figured I'd just cut away the clip haha), but much better to go with a full 8pin CPU/PCIe connector and just use 2-pins. I've bought this one: https://www.aliexpress.us/item/2251....0.0.6b9238daKSLqty&mp=1&gatewayAdapt=glo2usa

A very quick look suggests it's the same keyway at least. I suggest you check it's a good fit on the connector before powering up.

the classic test procedure (known as push, click, wiggle, pull):
1) push on (do not use any force that feels more than the cables you already have took, especially as you only have 2 terminals contributing to the friction)
2) did you hear a click? If not then it isn't fully home so assume the connection is not good
3) wiggle: move the connector left and right, no need for huge amounts of force!
4) pull back GENTLY - the connector should not move and the terminals shouldn't come flying out!

Copy on the fuse (1A it is!), will also make sure to place it close to my PSU. May I ask the reason behind placing it closer to the PSU rather then farther away. Also I should add that the distance between the PSU and the switch is 20-30cm or 8-12 inch, so not long at all.

The reason for the fuse being close to the supply is simply that it protects against short circuits for as much of the circuit as is possible.

To give you a better understanding of my project, i've decided to build the whole server inside a vintage 1960s military crate (I just cant stand the plastic PC/server cases haha), so the whole project will be DIY and the route cable management you've asked about will all be done inside the case. The only cable inputs that will be connected to the outside of the case are the 220v power cable (for Corsair PSU), all the swtich ethernet inputs and a individual RJ45 input that will be going straight to the switch and motherboard. Very unconventional I know, it's just how I like to roll haha

The build/case sounds interesting; I also see you are at least newly signed up so I recommend you consider starting a build log over in https://forums.overclockers.co.uk/community/project-logs.126/

Copy on the AWG 24 AWG (~0.25mm^2 with insulation diameter from 1.22mm) to 16 AWG (~1.3mm^2 insulation diameter to 3.15mm). Will probably go with 18 or 20 AWG, hit middle ground
*would you be able to share the link to the Molex website you got this info from

Again thank you for all your help, much appreciated

It's several links:
- The drawing and product spec (including the applicable terminal range data) are accessible here: https://www.molex.com/en-us/products/part-detail/39013085
- The terminal range is here (from clicking on the link on the first page of the product spec "45750"): https://www.molex.com/en-us/content...y=45750&taxonomyPathValueLast=Crimp Terminals

Deblocking tool was a question of searching for 5557 deblocking tool in Google, laughing at the price (as normal) and closing the page

I happen to know the connector range is called 5557 from a project at work before you wonder how I jumped to that

 

[Luc]

You are a real maestro sir. Thank you for all of this, I feel I am on the right path and all is well planned.

Will make sure to properly test the connections (push, click, wiggle, pull) haha

Btw found a off-brand version of your 5557 deblocking tool, in case youd want one for yourself, only 5$ haha

WinKool Professional ATX 5559 / 5557 4.2mm Pitch Spacing 24P 8P 6P 4P Power Connector Termainal Extractor Tool / Pin Remover - AliExpress 7

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[5abr3]

PS when choosing an inline wire fuse would you recommend a standard size fuse or a small/micro size?

The answer is "it depends" - spot the engineer

For what you are doing I would choose based on what inline fuse holders I can lay my hands on easily and cost effectively and what range of fuses has the right rating (and can potentially mount in the case if needed, see "it depends" ).

As you have a 1A load and I have an automotive background I would choose an ATO fuse and fuseholder as that's the only range that has a 1A fuse as a standard value out of the type range I usually use (you can get MINI that claim 1A ratings). Thanks to the naming of fuse ranges micro/small/standard aren't really a thing but you get trademarked ranges like MICRO2 and MINI that confuse things quite a lot.

The biggest headache last time I tried to do something like you are: it was sourcing a fuse holder that fit the packaging constraints I had and was commercially available in sufficiently small quantites, but I needed a few hundred per year and getting one or lots is a lot easier than ~100 a year in a work context and I couldn't justify 10,000 pieces when I needed 200+ a few spares/scrap.

You are a real maestro sir. Thank you for all of this, I feel I am on the right path and all is well planned.

Will make sure to properly test the connections (push, click, wiggle, pull) haha

Btw found a off-brand version of your 5557 deblocking tool, in case youd want one for yourself, only 5$ haha

WinKool Professional ATX 5559 / 5557 4.2mm Pitch Spacing 24P 8P 6P 4P Power Connector Termainal Extractor Tool / Pin Remover - AliExpress 7

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

Thanks, it's all the years fighting with datasheets and websites at work.

Regarding the tool: I'm able/lucky to be able to just use the official tool after figuring out who at work had one I could borrow over lunch though

 

[5abr3]

One more thought on the "push, click, wiggle, pull" side of things: as we don't know how good the tolerance stackup is going to be for your 5557 type 8 way and your PSU header I would recommend repeating the push step if the housing moves back when you do the pull check but doesnt come back off just to make sure the terminals and housing are fully inserted if you decide not to replace the housing.

It shouldn't be an issue on such a small load but better to be certain!

 

[Luc]

One more thought on the "push, click, wiggle, pull" side of things: as we don't know how good the tolerance stackup is going to be for your 5557 type 8 way and your PSU header I would recommend repeating the push step if the housing moves back when you do the pull check but doesnt come back off just to make sure the terminals and housing are fully inserted if you decide not to replace the housing.

It shouldn't be an issue on such a small load but better to be certain!

Hey 5abr3, thank you for the additional input, will definitely make sure to test the 8pin connector thoroughly.

Additionally, taking into consideration the custom case Im building, space is a bit ''limited/tight'', so I was planning on placing the PSU (Corsair AX860i) and the switch (Netgear GS108Tv3) relatively close together (about 5cm/2inch).

With such close proximity to each other, should I be concerened about EMI, RFI, EFI... or any other interfernace that could potentially disrupt the functionality of my devices? Or both devices being high quality build this shouldn't be an issue? *I plan to use shielded ethernet cables

An alternative idea for a solution to the interfernace issue was putting a plastic/metal sheet wrapped in foam (so its not conductive) between the devices to minimize the chance of this happening.

Would absolutely love to hear what your thoughts are on this and if my concern is of paranoid nature haha

 

[5abr3]

I wouldn't anticipate any issues, especially given they will be CE marked and the PSU and switch both have metal cases

Shielded Ethernet can't hurt you can spare the space for the stiffer cable where you need to bend it.

 

[Luc]

I wouldn't anticipate any issues, especially given they will be CE marked and the PSU and switch both have metal cases

Shielded Ethernet can't hurt you can spare the space for the stiffer cable where you need to bend it.

Fantastico, thats great! Thank you bud