SATA Power splitters in a server: Horrible idea?

I got my hands on a PowerEdge T140 and two OWC Accelsior S PCIe Adapters for 2.5" drives as boot drive, but It seems like the server doesn’t really like that PCIe adapter and the ASMedia SATA controller on the card itself sometimes doesn’t see the drive.

The idea is to just get a bracket like this to hold the two SSDs and add a PERC H330 to have space for 8 drives and get support for hardware raid for the boot drives:


There’s an issue though. This server is designed for maximum of 4 hard drives, and so has only 4 available SATA power cables for drives.

So how much of a terrible idea would be to use something like this to power the two SSDs?
I know the molex to sata ones are straight up a housefire cable, but apparently the SATA ones are safe.


I already have two SSDs and investing into a Dell BOSS card + 2x NVMe SSDs is currently out of my budget.

The drive configuration:
4x Seagate Ironwolf 2TB

I have no idea who launched the idea that Molex to SATA adapters are a fire hazard at any rate, 'cause they aren’t. Well, not if they use the correct wire gauge. Same goes for SATA to SATA cables like you’ve shown: if they have the correct wire gauge, they’re safe. If the gauge is too small, then either will be at risk of overloading, and theoretically can cause a fire.

As it happens, SSD’s are very power efficient and use a fraction of the power a regular HDD consumes. So, using any power adapter, even with underrated wire gauges, with SSD’s won’t be problematic. HDD’s however, are advisable to get the correct gauge wiring, especially on the power side.

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I’ve used worse DIY cables and they were totally fine. And the connector I was splitting from wasn’t even SATA, it was a custom 4 PIN to sata connector. The server in question was a shady looking 1U rack-mountable custom Intel server.

The reason why the cables were fine was because I was using SSDs. As Dutch_Master said, the gauge and having a tight / not shorted-out connection is important. The DIY cables were cut from molex-sata adapters and soldered to a 4 PIN CPU adapter that coincidentally fit in the server where the power output came from (I did check the wires with a multimeter to make sure I connected the correct wires, so I wouldn’t fry my ssds).

Usually wires melt because people use thin wires for HDDs or GPUs, or overload a PSU that cannot deliver enough wattage on the 12v rail that they plug the splitter on. Wires melting doesn’t necessarily mean that a fire will start, but they can be the cause of the fire. I’ve seen lots of molten wires from overheating / too much power draw and they never started a fire. But I wouldn’t bet on them not starting a fire, I prefer to be cautious. Splitters have a use case, but you have to know when it’s safe to use them (just like with any power cord, or other things involving electricity).

ITT I posted this pic:

Cable management wasn’t the best, the PSU was an old-ish Seasonic. I didn’t use it for long, changed it with just a slightly newer Seasonic with black cables, but I can’t find the newer picture / post.

Found the replacement, I pulled my hair trying to find it. ZFS RAID Config for old disks - #21 by Biky

Now you can clearly see which cables go where. You can see that I used a molex to 2x sata, one for a SSD and one for a HDD. The rest of the cables were sata only, so I wasn’t splitting from the same cables, however, I didn’t check to see which rail the molex connector came from. But this configuration worked, because there wasn’t a lot of power being drawn through one cable. These were Seagate Constellation 2TB drives. I had 4 HHDs connected by 1 cable with 4 sata connectors (the ones on the bottom), 3 HDDs + the SSD connected to another cable that had 2 sata and 2 molex (only 1 used) and the last 4 HDDs in the 5.25" bays powered by another cable with 2 molex connectors. So 3 cables powering 4 drives each (well, technically one only had 3, because the SSD was consuming peanuts).

So, if you got only consumer ssds (enterprise ones tend to consume a lot more), it should be fine to split. If you want to split cables for HDDs, I suggest you don’t do more than 5 per single cable at most as a rule of thumb. If your PSU doesn’t have more cables, get one that does.

It’s a good idea if you have consumer SSDs or if you don’t have really power hungry enterprise SSDs.

As Dutch_Master said, this is false. All it matters is that you know when and how to use them.


Unfortunately the fires are a real thing, though they don’t seem as prevalent anymore. Basically the issue is that cheap poorly made molded sata power connectors can degrade and catch fire, of which there are copious examples online. Here’s a good video that breaks down why this was/is likely happening: What's Inside the Bad Molex to SATA Adapters (And Possible Failure Modes) - YouTube

Essentially it’s the pins within the connector shorting out, not the wires themselves. There’s no good way to tell if a molded connector is good, or fire hazard. So the safest thing to do is to use cables with crimped sata connectors.

If that’s done, then yes, all that’s needed at that point is to respect the gauge/length amps limit of the cables.

I personally would be fine with molded connectors from a reputable brand, like cablematters, but I don’t begrudge anyone’s paranoia.


The style of connector in your image is the crimped version, which is safe.

Same with this molex to sata:

See my previous post to see what the fire hazard actually is from. Crimped connectors avoid the shorting issue entirely. Hell, you can make your own if you have the tools.


Yeah, my molex pins were crimped too (which were kind of a pain TBH, because inserting them in the male connector when they juggled around wasn’t easy). Didn’t know about the crimped thing, but I knew shorts are usually the reason wires melt (which I mentioned in my post).

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Can you post a picture of the one from the Amazon link or one just like it, please. Because I am outside the US Amazon redirects me to some random adapter search page. I want to know what to look out for when I need to buy one again.

Here’s a low quality one since I only have my work iphone, and apple is walled garden garbage that hates power users.

Here’s some more examples of what they look like apart. ModDIY is where I generally go when I rarely want to make custom cables for something.

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Well, in either case, the PSU is at fault here. A short should lead to a full shutdown of the PSU, especially on the 12V rail to GND. But if the wiring, by being too thin, gives enough resistance to prevent the short circuit protection to not see the short, it’s the wrong wire gauge.

For HDD’s and modern GPU’s (nVidia 2000 series and up, AMD 5000 series and up) use 16-18AWG wires in any splitters/adapters, for SSD’s 20-22AWG will do fine.

The company I currently work for does exactly that. Be it for industrial, not enthusiast customers. So we don’t have SATA nor 4-pin Molex connectors in the warehouse :frowning: But, if I bring my own parts, I’m fairly sure I’m allowed to make stuff in my own time when I ask nicely :wink:

(NO, I’m NOT running a bespoke cable making service for 3rd party consumers :stuck_out_tongue: )

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Its two Intel SSD DC S3520 Series SSDs and the PSU is the custom weird 12v only standard

The data sheet for both the Ironwolfs and DC SSDs show good power effeciency, so 27.5 Watts at works won’t do any harm

I’ll give the crimped version a go once I get a confirmation from OWC Its not a DoA card and get the bracket

I had a cheap molex to sata splitter burst into flames.
Was exciting and fun, with a side of noxious fumes.

It seems the cheap adapter shorted at the sata connection side, causing the plastic around the adapter point of contact with the HDD exothermically excite.
The system had been running fine for like 15 days of light load, and i happened to be near it when the yellow flames and black smoke started billowing out…

The short melted the pins of the drive it was attached to , and made some flames, but no other damage, so I’m happy with that; one drive and a cheap splitter was a cheap lesson.

I guess properly crimped cables are probably a sign of not terrible workmanship, but I switched to using modular supplies that I can just connect a proper cable to. Definitely over-reaction, but again, lesson learned, “once bitten, twice shy” and all that…


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