Sham dual rail

[NeoPTLD]

I tore into a 300W Seasonic power supply and found something interesting. It is labeled 12V1 17A, 12v2 17A, combined total 288W, or 24A but they're all soldered into the same bundle rather than having two separate bundles each having their own monitoring shunt. So why doesn't the rail just say 12v 24A? The idea behind multi-rail is to prevent a wire from becoming severely overloaded such as when someone connects a two Molex to PCI-E adapter to two Molex connectors from the same string.

Given a duplex outlet served on a 20A circuit and you plug in two power strips each with a 15A breaker, you have a dual rail, because each power strip protects itself to 15A while the 20A branch circuit breaker serving the power strip limits the total load at 20A. If you had unprotected 15A rated power strips, the only protection is from the 20A breaker upstream and there's nothing preventing you from loading one power strip to 20A.

 

[Harald]

Bit of a late answer, but this is common on a lot of older Seasonic PSUs. (not all, mind you) It says they have OCP on the rails, but turns out they do not. I remember when Corsair got their HX520 and 620s out on the market, they were based on the Seasonic S12 platform, and according to Seasonic, they were supposed to have 3x18A rails. But in reality those two models were a 40A and 50A single rail PSUs, which caused confusion among potential buyers. Some were put off by the prospect of the (non-existent) split rails because of the FUD that was circulating back then thanks to you-know-who. (PCP&C, in case someone forgot). Anyway. not sure why Seasonic did this. Maybe they wanted to comply with the ATX standard, even if it was just on paper. A bit silly really.

 

[jmmtn4aj]

Bit of a late answer, but this is common on a lot of older Seasonic PSUs. (not all, mind you) It says they have OCP on the rails, but turns out they do not. I remember when Corsair got their HX520 and 620s out on the market, they were based on the Seasonic S12 platform, and according to Seasonic, they were supposed to have 3x18A rails. But in reality those two models were a 40A and 50A single rail PSUs, which caused confusion among potential buyers. Some were put off by the prospect of the (non-existent) split rails because of the FUD that was circulating back then thanks to you-know-who. (PCP&C, in case someone forgot). Anyway. not sure why Seasonic did this. Maybe they wanted to comply with the ATX standard, even if it was just on paper. A bit silly really.

What kind of FUD was PCP&C spreading?

 

[theAnimal]

What kind of FUD was PCP&C spreading?

That multi-rail PSUs were bad.

 

[Rifter]

That multi-rail PSUs were bad.

Yeah that was sad, when in reality they are fine, was just a few idiots hooking up high powered GPU's to the wrong rails that wernt rated for the draw that gave them a bad name for a while there.

That said there is something to be said for the simplicity of a single rail PSU. Kinda impossible to hook it up wrong as long as system power is not over PSU power you are good to go.

 

[NeoPTLD]

Bit of a late answer, but this is common on a lot of older Seasonic PSUs. (not all, mind you) It says they have OCP on the rails, but turns out they do not.

What's old? The manufacturing date on this one is July 2014.