I am just thinking ahead, but I currently have a case with 9 external bays (hold 15 drives with 5 in 3 cages).  Has anyone ever fixed a 5 in 3 cage externally to squeeze a few more drives in?  My case has opening to run the sata cables and molex connector to power one.  And my power supply should cover 20 drives.  Anyone do that before?  Not recommended?  Just wondering.

There isn't any reason why it wouldn't work, just make sure you have it secured so that the cables and or cage are not able to be jostled about too much, I'd suggest at minimum locking sata cables and hopefully no pets or kids around who like to mess with stuff like that.

 

It will expose cabling to possible outside elements (pets and children) that normally don't mix well with cables, but if that's not an issue and you don't mind the appearance it shouldn't really hurt anything.

i have for the moment a 4 in 3 cage laying on top of my unraid box

fed by an extra powersupply sitting in the back of my desk

the 4 in 3 is held onto place with velcro strips...

 

disks are on my br10i with the 50cm breakout cable

 

have no issues with it