I have 3 Norco SS-400s in my almost ready to be setup server. Each of those Norcos require 2 4pin molex connectors for power. Here is my question. I moved my semi-old Corsair HX750 into my server when I upgraded my gaming system figuring it would future proof part of my server if and when I decide to upgrade to more drives. I found out that the HX750 only has two leads with 4 molex connectors each (total of but they are so close together (hooking up to normal components probably would not matter) that I can only use one lead of four per Norco.

 

I was contemplating using one of the leads that has 4 SATA power connectors on it and purchasing three 15pin SATA Male to Dual Female 4 pin Molex connectors (http://www.newegg.com/Product/Product.aspx?Item=N82E16812226018) or would that be pushing my luck? The other option would be to buy six single 15pin Male to 4pin Female Molex (http://www.amazon.com/gp/product/B001JE6WYY/ref=ox_sc_act_title_1?ie=UTF8&smid=AJJDLHUCVHEJC) and use two leads instead of just one. Any suggestions?

The reason for the drive cages having more than one power connector is that the potential maximum current drawn by a fully populated cage exceeds the maximum current specification of the power connectors - hence the cages are designed to share the current current between two (sometimes three) connectors.

 

Using power splitters merely circumvents the attempts by the cage builders to observe good design practice.

The reason for the drive cages having more than one power connector is that the potential maximum current drawn by a fully populated cage exceeds the maximum current specification of the power connectors - hence the cages are designed to share the current current between two (sometimes three) connectors.

 

Using power splitters merely circumvents the attempts by the cage builders to observe good design practice.

 

I've read (and tested with 4x 7200rpm drives), the Norco SS-400 referenced have two power connections for redundancy.  Only one is required unless you put in some super power hungry hard drives with a low amp PS (in which case you have other issues).

And sadly, without dual power supplies [sigh] pointless for most of us

Piggy backing power supplies isn't too big of an issue once you buy the second power supply. Had to do it for our bitcoin rigs.  Each board has 5 cards requiring an absurd amount of power so there are two 850W PSUs per rig.

 

Totaling 516A @ 120/110v

 

Got heat?

I've read (and tested with 4x 7200rpm drives), the Norco SS-400 referenced have two power connections for redundancy.  Only one is required unless you put in some super power hungry hard drives with a low amp PS (in which case you have other issues).

 

The old four-pin molex connectors are rated at 11A per terminal.  Since it is commonly recommended here that 3amps spinup current should be allowed for a non-green, 7200rpm, drive on the 12V rail, you can see that a fully populated 5 bay cage can exceed the rating of a single connector.

 

It's even worse if the cage uses the new 15-pin SATA power connectors.  Each pin on the SATA connector is rated at 1.5 amps.  However, the SATA standard calls for each rail to use three pins in parallel, allowing for 4.5 amps per rail.  However, only five pins are mandated for the ground connection, so the maximum current across all three power rails is limited to 7.5A.  This probably explains why some five bay cages provide three SATA power connectors.

 

Redundancy or necessity?  I know what I believe!

 

I've seen the result of passing too much current through a molex connector - the melted nylon shell makes a mess!

I've read (and tested with 4x 7200rpm drives), the Norco SS-400 referenced have two power connections for redundancy.  Only one is required unless you put in some super power hungry hard drives with a low amp PS (in which case you have other issues).

 

The old four-pin molex connectors are rated at 11A per terminal.  Since it is commonly recommended here that 3amps spinup current should be allowed for a non-green, 7200rpm, drive on the 12V rail, you can see that a fully populated 5 bay cage can exceed the rating of a single connector.

 

It's even worse if the cage uses the new 15-pin SATA power connectors.  Each pin on the SATA connector is rated at 1.5 amps.  However, the SATA standard calls for each rail to use three pins in parallel, allowing for 4.5 amps per rail.  However, only five pins are mandated for the ground connection, so the maximum current across all three power rails is limited to 7.5A.  This probably explains why some five bay cages provide three SATA power connectors.

 

Redundancy or necessity?  I know what I believe!

 

I've seen the result of passing too much current through a molex connector - the melted nylon shell makes a mess!

 

Luckily the unit in question is neither a SATA power connection or 5 bay unit, so we're pretty close to spec

 

Note, I still run two myself.

 

I use a SS-500 (5 in 3) with 1 Molex connector and it runs fine using 5 drives (3 7200s, 2 Greens)

I use a SS-500 (5 in 3) with 1 Molex connector and it runs fine using 5 drives (3 7200s, 2 Greens)

I tore the tag off my mattress, and never got arrested.

["Are we learning yet?"]

 

--UhClem  "Life is such monotony ... without a good lobotomy."

 

Piggy backing power supplies isn't too big of an issue once you buy the second power supply. Had to do it for our bitcoin rigs.  Each board has 5 cards requiring an absurd amount of power so there are two 850W PSUs per rig.

 

Totaling 516A @ 120/110v

 

Got heat?

 

Where did you get a 600A, 120V service and you make money when paying something like $250 per day for hydro?

Usually the Molex gets brittle, slightly discolored, and the pins can get oxidized if you pass too much current for an extended period of time - very extended. I used to repair old hardware that used these and we often had to swap the connectors and scrape the oxidation off the pins to bring the voltage back to spec. Our connectors never melted but I guess cheaper ones might. The failure took ages and there was little ventilation so the Norco might avoid this altogether simply because there's airflow.

 

Honestly, using both connectors and two different rails to load balance is probably smartest. I'll admit I'm not in my 4224 but I also expect to be making custom cables for power and will do so then. The Norco is nice for taking standard PSU but the extra cables really interfere with airflow IMO. The 3ft Mono price SAS cables are also a real problem - eBay is a good source for shorter ones. When you make shorter power cables you can also use gold covered pins to help with power transfer fwiw.