Hello [NAME] I think I've found it. I have to confess it was not an easy task.. but I found Dell Part Number # 42Y6C. Description says: ASSY,CBL,PWR,BKPLN,2S+4HD,R620 - BP Power cable for 2+4HDD (from M/B to BP) Sounds good to me. What do you think?Please, let us know if you need any more help.   Regards.    
We have ordered some NJW0R backplanes to upgrade R620 4-bay backplanes to 6-bay backplanes (4X SAS/2X PCIe). The backplane fits well but the power and control cables from 4X are not suitable. Just to mention that the original backplanes are sold without cables included.  Could you please give a list of necessary cables for this backplane (NJW0R)? 
Cables for 4X/2X (SAS/PCIe) backplane on R620