Is this what you're looking for?  https://www.amazon.com/s?k=sata+power+splitter&ref=nb_sb_noss 

Whether you use the 12v rail that powers the HDD's, or the 12v rail that powers accessories, like DVD drive(s), shouldn't make a difference.  SSD's are only 5v.

Hi @omarberr, sorry I can't help you to find the good cable. I would like to ask you for advice to mechanical install of a 3rd SATA HDD 3.5" into the 5.25" bay, do you need extra spare part to fit the 3.5" HDD?

I can't install my 3.5" HDD into the last bay (beside the NVMe drive) because it isn't a SATA port.

Bests,

Luan

Upgrading Storage in the Dell Precision 5820 | 7820 | 7920 Tower Workstations 

Please let me know if this helps.  It has specific part numbers.

For a search term in Google and/or Amazon, one can enter "3.5 inch hard drive to 5.25 inch drive bay adapter."  But in case you need a specific adapter and not a one size fits all, I held off on suggesting adapters, some of them being hot swap.

While a DVD-RW drive can be inserted into almost any 5.25".bay for example, I recommend the above article in case another part is needed.

@omarberr 

Please press the blue Accept as Solution button below if the post answers your question.

There is a reason why Sata power has multiple wires. The connector you are pointing to has 12v only on it.  You can safely use a splitter for multiple SSD drives.

SATA POWER SPLITTER CABLE

CABLE

Thread was started in Aug. 2020, so hopefully that part was solved.