PSU tier list 2.0

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Not necessarily; an isolated transformer will have two cables with an AC voltage between them, but no connection to ground, and neither is 'hot' or 'neutral'. We usually ground one of these conductors, making it the neutral, or grounded conductor - the other is now the 'hot', or ungrounded conductor.

In DC there are 3 also, positive-negative-ground. Negative and neutral are sometimes confused with ground and sometimes used by grounding. In a psu, after the AC-DC conversion, there should be nowhere that negative touches ground.
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Negative is, by convention, generally connected to and shares the same conductor with ground. Grab a multimeter - you'll find that the ground pin on the plug, the black ground wires in your PC, and the metal chassis are all connected.

In a double-insulated supply like a phone charger, the negative output wire will be connected to the device's ground plane (the outside of the USB cable, and the case), but not the input ground because it doesn't have a ground pin.

Ground serves 2 purposes, first is safety, a pathway back to source in the advent of component failure, and the second is antenna. Any and all outside rf /static frequencies that would induce/interfere with the workings of the psu are shunted harmlessly away.
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Safety is the main one; unless the device is double insulated, the chassis must be grounded (or in some cases in the US, on a GFCI). This ensures that a single fault cannot make the chassis live, because it would trip the breaker.

Negative is different, that return path carries the unbalanced load, the leftovers from what's actually used.
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Not really the 'leftovers', just the return current.

A psu will work ungrounded just fine but not for long. What'll invariably happen is static charge will build and have no outlet until it creates one somewhere via short to a powered component where the differential in polarities will act as an attraction, like 2 magnets. Bye bye motherboard
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So how does a cellphone charger work? No ground there...

Static dissipates naturally, and shunting it to either live or neutral via a MOV or similar works perfectly fine due to the tiny currents.


On the low side of the switchmode output.
 


Fortron is FSP.
 
In my country people like to buy Fortron Hexa 400w and Fortron Raider 650W... What do you guys think of them?

Raider doesn't seem like a bad unit

I'm still suggesting seasonic and xfx to them (we don't have EVGA units in our country) however im interested in how good are these two from fortron
 


Protections (AKA safeties) are requirements that all PSUs must have, at least overcurrent protection, overvoltage protection, and short circuit are required. Only problem is that sometimes they are very crappy and don't trigger on time or detect stuff fast enough.

As for efficiency, yada yada. Doesn't matter too much compared to voltage stability and ripple.

Look at the 12V voltage regulation here http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story4&reid=310 - bad.
 


Although those units are undoubtedly tier 5 qualified, there really are NO in depth reviews of any units, much less global use of them, being mostly regionally oriented to only India and the middle east Flipkart/Snapdeal regions. I'd agree they belong there, just not sure we can condemn them in toto without some factual review data to back it up.
 
Phone chargers work on line in hot through a step-down coil and out the neutral. There is no ground needed as it's all plastic casing. If, like some older power strips, the casing was metal then you'd need a ground just for safety concerns.

As I said, sometimes ground is used as the return path for the negative, that doesn't make it right, there should be no place other than in the main breaker panel where neutrals and grounds are connected via bond. A grounding and a grounded conductor should be 2 separate things.
As far as return current, in a 120v circuit, there isn't any as such, just voltage and resistance from the conductor inducing amperage, the unbalanced load.

Maybe because I work with high voltage and amperage the rules are different than what's accepted for low voltage applications.
 

Double insulated gear can still have a metal case - DVD players are a common example, I've found. It just has to have an extra layer of insulation.

Also, you can touch the connected-to-negative metal shield of a USB charger very easily.

As I said, sometimes ground is used as the return path for the negative, that doesn't make it right, there should be no place other than in the main breaker panel where neutrals and grounds are connected via bond. A grounding and a grounded conductor should be 2 separate things.
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Neutral and negative are not the same. Given that the power supply is the 'source' of the ELV DC, it's reasonable for it to ground the negative conductor. As you say, the supply neutral should not be grounded inside an appliance, and doing so would trip any RCD/GFCI.

As far as return current, in a 120v circuit, there isn't any as such, just voltage and resistance from the conductor inducing amperage, the unbalanced load.
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Return current = supply current. Current is the same in all points of the circuit due to Kirchoff's Law. Unless this is not what you're talking about?

If there's 20A going out of the PSU on the +12V rail (and ignoring all other rails), there will be 20A returning via either the ground wires within the PC (e.g. the black wires on the CPU power cable) or the case.


And that circle goes via the secondary winding of the power supply transformer.
 


Now it makes sense! Thank you.
 


Depends on the price difference. With the P2 you get better ripple suppression and higher efficiency, and longer-lasting cable inline capacitors. If you already have a 650W Seasonic IMO I don't see a dire need to upgrade, unless you want to. And with the P2 you avoid the PWR_OK problems.
 
My 780ti is also a highly, factory, overclocked model. Only the Kingpin is clocked higher.

http://pcpartpicker.com/part/evga-video-card-03gp42888kr

If this were just a gaming rig, I wouldn't even care, and I will probably drop folding, for the hotter summer months. But that is quite the load to have 24/7. Mine has a higher max load wattage, that even a 290x. That is why I ignore Nvidia fanboys using the power consumption argument, with regards to the 390.

power_maximum.gif
 
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