Question Can A Slightly Frayed PSU Cable Harm My Motherboard?

Clueless02

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Hello All,

It's been a while since I've built a computer, but I decided to take my new free time staying at home to make a new custom build.

Since it'll be about 7-8 years since I build one after this I decided to, relatively speaking, go all-out. I wanted a challenge so I went the mini ITX route. I got an X570 mobo and put it in an InWin A1 plus chassis, which has an integrated 650W Gold PSU. At the end during cable management I took the PSU cover (used to hide the PSU from the glass side) off and noticed that at the factory, they had clipped one of the cables, fraying it very slightly but exposing the bare wire which is also damaged slightly.

I wrapped it in electrical tape and replaced the shroud and the system is operating fine. However, upon sleeping on it, I'm a little worried this could damage the motherboard over time. Google didn't really yield many answers so I figured I'd turn to you good people. Any thoughts?

Cheers,
 

Ralston18

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I would do the same.

The key is to prevent an electrical short and if you wrapped the cable with good quality electrical tape then all should be well.

Just check the "wrap" every so often to ensure that it is not unraveling and eventually allowing some electrical short to occur.
 

Karadjgne

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Depends on the extent of the damage. That's stranded wire, lots of really tiny hair size strands twisted together. If there's enough damage, too many strands are cut, the that lowers the possible amperage the wire can transmit. That won't affect the motherboard, but can affect the safety of the wire. It's now a weak point.

If it's just exposure, then a decent tape job is no different than the prior insulative coating, if it's actual damage, that's different.

If you have any doubts, take a picture of the damage, send it to InWin, and ask for a replacement. If it's not replaceable, tell them to send a new psu.
 
Hello All,

It's been a while since I've built a computer, but I decided to take my new free time staying at home to make a new custom build.

Since it'll be about 7-8 years since I build one after this I decided to, relatively speaking, go all-out. I wanted a challenge so I went the mini ITX route. I got an X570 mobo and put it in an InWin A1 plus chassis, which has an integrated 650W Gold PSU. At the end during cable management I took the PSU cover (used to hide the PSU from the glass side) off and noticed that at the factory, they had clipped one of the cables, fraying it very slightly but exposing the bare wire which is also damaged slightly.

I wrapped it in electrical tape and replaced the shroud and the system is operating fine. However, upon sleeping on it, I'm a little worried this could damage the motherboard over time. Google didn't really yield many answers so I figured I'd turn to you good people. Any thoughts?

Cheers,
I agree that wrapping it with electrical tape is probably good enough. But I'd be worried about the wire itself since you said it's also slightly damaged. It may be nothing, but if individual strands of the multistranded wire were broken it reduces the effective current carrying capacity of the wire. If enough strands were broken and it's carrying heavy currents it will have a bigger voltage drop than normal, causing attached devices to malfunction. But worse, possibly get hot in the area of the damage.
 
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Clueless02

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I agree that wrapping it with electrical tape is probably good enough. But I'd be worried about the wire itself since you said it's also slightly damaged. It may be nothing, but if individual strands of the multistranded wire were broken it reduces the effective current carrying capacity of the wire. If enough strands were broken and it's carrying heavy currents it will have a bigger voltage drop than normal, causing attached devices to malfunction. But worse, possibly get hot in the area of the damage.
That's what I'm thinking, especially if I put a big GPU in there which will draw more. The damage in on the 24 pin connector for the mobo. I reached out to Inwin but they haven't responded.
 

Karadjgne

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No voltage drop. You'll read the same voltage on 1 strand as in 1000. What'll happen is the same amperage gets pulled through a smaller gage, which creates higher resistance, and higher heat in a cascade effect until the wire literally melts, creating a short, which has a welding affect creating massive heat output which fully seperates the wire.

That's when the protective circuitry of the psu should have kicked in, at the short, whether it be SP or OCP or OPP. Hopefully. If it's a substandard psu, good luck with anything stopping the short, and the insulation catches fire. You see this most often in adapters, the main reason they are simply not recommended if changing ability, like a molex to 6pin or 6pin to 2x 6pin etc.

Worst case scenario btw, a single 18ga wire is good for @ 10DCA at 12v, that's 120w, and almost nothing pulls anything close to that on a single lead , usually half. So a few strands is fine, but if half or close are toast, the wire is toast.
 
No voltage drop. You'll read the same voltage on 1 strand as in 1000...
That's not true. Loss of enough strands in a wire will be the same as reducing wire gage it could effectively drop an 18 ga wire to a 20 ga wire. That's effectively the same as putting resistor in series at the break and surely you must know a series resistor WILL drop voltage?

You know that it gets hotter, so you must know that getting it warm means it's presenting a load and dropping voltage. Kirchoff's law (slightly restated): the sum of the voltage drops (across loads) in a circuit equals the voltage applied to the entire circuit. If you read the voltage from the PSU at the output pins and ground pins at the PSU you'll read E(applied). If you read the voltage across the broken strands you'll read E(break). If you read the voltage across the GPU (from the 12V pins to the ground pins of the GPU connector) you'll read E(gpu); E(break)+E(gpu)=E(applied). This is simplified, of course, to ignore losses in the undamaged conductor sections.

As the number of broken strands increase, inevitably E(break) increases and therefore E(gpu) MUST decrease. This is basic DC analysis in electronics

Why do they tell us a PSU using 20ga wire can make GPU's unstable in heavy use? It's not because the conductors can get warm...it's because the voltage drop is greater across the conductor, making the voltage available at the GPU lower and unsteady with changes in current as the load varies.

Go play with a voltage drop calculator a little bit, you'll see.

IF there are broken strands, the best repair for this would be to cut the damaged area of the wire out and put a properly sized compression splice in. But replacing the cable entirely is an even better option if these are modular cables.
 
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...The damage in on the 24 pin connector for the mobo....
Can you determine exactly which pin that wire connects to? It may be one of the un/under-used voltages (like -12 or +3.3) or a signal lead that only passes extremely light currents (like Power OK signal or the turn-on leads). In which case it's a tempest in a teapot; leave it wrapped in black electrical tape, tuck it away in the bundle to hide it and go about using your system with out worrying.

Even if it's one of the +12 leads, a clever person could unpin it from it's location and swap it with one of those light loaded leads. You'd have to do the exact same swap at both ends, so that of course needs a modular cable with connectors at both ends. But assuming your PSU is one of the full-modular cable variety also means you should be able to find a replacement cable if the mfr. doesn't help.
 
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Clueless02

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First of all, thank you for the responses. You guys are a big help to someone like me who doesn't have a local group to seek advice from.

Annoyingly, these aren't modular as that would have been the easiest fix and I have spare cables from my old PSU. I'll look tonight as to which specific wire the fray has occurred and report back. In the meantime, I attached a link to the photos I sent to InWin. It's not major, but if you zoom in some of the wires are clearly split where the screw from the shroud caught it.

Dropbox Link
 
First of all, thank you for the responses. You guys are a big help to someone like me who doesn't have a local group to seek advice from.

Annoyingly, these aren't modular as that would have been the easiest fix and I have spare cables from my old PSU. I'll look tonight as to which specific wire the fray has occurred and report back. In the meantime, I attached a link to the photos I sent to InWin. It's not major, but if you zoom in some of the wires are clearly split where the screw from the shroud caught it.

Dropbox Link
Yeah...I'd want to repair that too. Hopefully InWin will help, so by all means keep working them.

But should they not do anything for you, and if it's not one of the lightly loaded wires, I am a bit OCD about these things (having worked in aerospace) so I'd go the route of putting in a crimp-style butt splice to fix it with a piece of black heat shrink to cover it up. You can pick up crimp style butt splices for 18-20 ga wire at any big box hardware store (Lowes, HomeDepot in the US). Pick up the crimping tool too, it's pretty important to do it right and not that expensive if you get the DIY'ers version and not the Pro's version. Cut the smallest section out that you can and strip it back then crimp on the butt splice...instructions should be on the package.

If you enjoy doing these techy things, get a butt splice kit with a variety of sizes and a crimp tool included. It's a great thing to have around.

The butt splice will probably be red and ugly, that's why the heatshrink tubing. So pick that up if it matters. And don't forget to slip it on before you do the final splice. That's so annoying to forget.
 

Clueless02

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I feel you, this is something my OCD won't likely let me forget either. I'm pretty bummed/annoyed about it but I just keep reminding myself that with everything going on, this is hardly a real problem. The electrical tape is like speed tape on a plane, only good for so many fights

Unfortunately, I can't tell which connector it is in the 24pin slot. This case is tiny and with the wraith Prism cooler attached, you can barely see anything once the cords have been zip tied.

I guess my final question, in short, is: Until I can get a more permanent fix/ InWin responds, will there likely be any long term damage to the CPU/ Mobo with this setup? Let's assume the worst-case scenario and the damaged wire is baring a significant load.
 

Clueless02

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Yeah...I'd want to repair that too. Hopefully InWin will help, so by all means keep working them.

But should they not do anything for you, and if it's not one of the lightly loaded wires, I am a bit OCD about these things (having worked in aerospace) so I'd go the route of putting in a crimp-style butt splice to fix it with a piece of black heat shrink to cover it up. You can pick up crimp style butt splices for 18-20 ga wire at any big box hardware store (Lowes, HomeDepot in the US). Pick up the crimping tool too, it's pretty important to do it right and not that expensive if you get the DIY'ers version and not the Pro's version. Cut the smallest section out that you can and strip it back then crimp on the butt splice...instructions should be on the package.

If you enjoy doing these techy things, get a butt splice kit with a variety of sizes and a crimp tool included. It's a great thing to have around.

The butt splice will probably be red and ugly, that's why the heatshrink tubing. So pick that up if it matters. And don't forget to slip it on before you do the final splice. That's so annoying to forget.
I've never done this before, but do you think it'll be a permanent fix? I just youtube it and it seems like an easy fix, even more so than replacing the integrated PSU
 
...
I guess my final question, in short, is: Until I can get a more permanent fix/ InWin responds, will there likely be any long term damage to the CPU/ Mobo with this setup?....
I'd also go with "probably not", even if it's on a +12V wire. Reason being, in modern systems the heavier loads go to the CPU and discrete GPU, which are carried on their own cables and connectors.

My main concern, if I had that situation, is if the tape comes loose and leaves a bare conductor to contact chassis ground. That's why I like the butt splice with heatshrink; it leaves it very reliable.

EDIT add: And yes, so long as you 'bottom' the tool when you make the crimp it's very reliable. The pro tools have a ratcheting mechanism that forces you to bottom the tool or it won't release the splice.

And oh yeah...get some extra splices and practice on some scrap wire!
 
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I've never done this before, but do you think it'll be a permanent fix?...
And BTW, with the hundreds of miles of wiring on a typical airplane you must know this type of thing is not an uncommon occurrence. They don't fish out wires running in fuselage bundles when it happens. When circumstances warrant it's a standard repair and the techs just get QA approval, whip out the butt splice kit, follow the spec to select the right ones and crimp it and heat shrink. Of course the splices are different, with moisture tight seals on the sleeving, but the concept is the same leaving a repair that's aerospace ultra-hi reliable.
 
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Clueless02

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This is so true (worked in aviation from the finance side), thanks for the advice. I was feeling bummed out and not thinking.

A butt splice is probably better than a solder as well right? Never done it but basically cut out the damaged bit and peel back the insolation -> put both ends into the butt kit and heat it to seal the ends. Sound about right?
 
This is so true (worked in aviation from the finance side), thanks for the advice. I was feeling bummed out and not thinking.

A butt splice is probably better than a solder as well right? Never done it but basically cut out the damaged bit and peel back the insolation -> put both ends into the butt kit and heat it to seal the ends. Sound about right?
The thing about soldering or using a solder stub splice (if I understand you right) is that you have to use a heat gun that generates enough heat to melt the solder. I'm really doubtful the insulation of the wire will handle that. Most aerospace wire is a form of teflon or other polymer that can take a lot of heat, not so consumer electronics.

And then, from an ultra-hi reliability and safety perspective we never used them. If a short circuit occurred it can raise temp of the conductor to the point the solder would melt letting the conductors come loose. You want the splice to hold no matter what, until circuit protection kicks in and shuts down the device or at least doesn't worsen a bad situation by letting live, bare conductors flop around in tight spaces.
 

Karadjgne

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Voltage drops occur because of resistance x distance. At 18" or so, 12ga or 30ga will read the same. It'd take closer to 60'+ to make any noticable difference. It takes over 200' to see any difference between 10ga and 12ga. Wire guage won't affect voltage in common psu lengths, only current capacity and therefore power limits.
 

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