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For two SATA SSDs I want to crimp one or two 15-pin SATA power cables with a length of about 30 cm (12 inch). Since space is a concern, I want to use cables thinner than AWG 16/17/18.

I know that SATA power cables can manage high currents, but this may be also due to historic reasons. Nowadays we have SSDs and the two SSDs (Samsung PM893) I want to use are rated with DC+5V at 1.3 A (= below 7 W) each.

Can I therefore assume that it is safe to only use AWG 23 for the 15-pin SATA power cable? Of course it will not burn, but could voltage drop be an issue?

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  • \$\begingroup\$ Well, you could start by calculating how much voltage could drop through the wiring and connectors. Take also power supply output tolerance into account. The compare that with SSD datasheet if it is still withing accepted range or outside it. \$\endgroup\$
    – Justme
    May 18, 2023 at 16:29

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23 AWG wire is about 66.8 Ω/km, for 20 mΩ over your 30 cm run. 18 AWG wire is about 20.9 Ω/km, which is 6 mΩ for 30 cm. At 1.3 A, this equates to a voltage drop of 26 mV for the 23 AWG wire and 8 mV for the 18. The difference is about 0.36% of the 5 V rail, or, to put it another way, 7.2% of the overall 5% of the allowable tolerance for the 5 V rail. Will this be a problem? Without knowing the input voltage tolerance of the SSDs and the accuracy of your power supply (probably a bit wider than 5% for the one, probably well within 5% for the other) it's hard to say, but probably not. I would definitely run the system for a bit before putting it to work on anything really important.

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