The supply should be under it’s intended operating conditions (which should also be a somewhat stable load) to achieve best results when adjusting. You can initially adjust it under close conditions, however be sure to check all adjustable output levels once it is under its intended operating conditions. If you intend to power up the supply without connecting it to a computer, be sure to read the supplies label first, many power supplies list MINIMUM current loads for the different voltages. It is highly recommended you load ALL the outputs to a level that exceeds their given minimum loads, but does not exceed their given maximum loads, before powering it up. Although I've not used one myself, several inexpensive power supply test boxes are available that are suppose to do this, check out some of the on-line “wholesale” hardware sites for details. If you decide to obtain one, be sure it meets your particular supplies loading requirements. You will still need to be wary of the scenarios described in my last reply, in addition;
As to the wire gauge "thing," you will not eliminate the voltage loss of a direct current run; you will only moderate it and its subordinate effects to some degree. Yes, the value of parallelled resistances is the average of the value of each separate resistance; in this situation, you rapidly reach the point where a large gauge addition makes very little difference. That’s the math, i.e.; the "nature of the beast."
With D.C. the load is resistive, where with A.C. the load is inductive. Resistive == voltage, inductive == current. Voltage is determined by the source, Current (load) is determined by the demand. (Although in general, a demand that exceeds a source's capability will cause a voltage drop.) Furthermore, the load (demand) determines the actual effect of both a resistor and an inductor. With a resistor, no load equals no voltage drop, as you increase load the voltage drop increases too. With an inductor; as you increase load, the current loss caused by the inductor itself increases. Elimination of the resistive and inductive losses encountered in D.C. and A.C. power transmission has another name, it’s called superconductivity.
What would be best? To locate a supply that has remote sense lines for the different major voltages. This is common with (other than pc) much of the electronic equipment of the world. In this scenario, each voltage has a +, a -, a sense + & a sense - ; you connect the sense lines to the point at which voltage regulation for the particular voltage is desired. Note that the sense wires themselves suffer negligible voltage drop because the sense circuit causes very little load, it is a “signal.” But why go to such an extreme? As the actual voltage drop incurred in D.C. power transmission is determined by both the distance (wire length) and load (demand); the further away from the regulation point one gets, the more the voltage will vary for a given change in load. Computer’s demands (loads) tend to vary substantially, constantly and quite rapidly. The result? Lots of hf, mf & lf noise at the machine as the power runs grow in length. A dvdm won’t reveal this, it requires a reasonably fast oscilloscope to see. You may not suffer obvious difficulties; any damage may be far subtler, in fact, it may not rear its ugly head for some time.
I’ve seen high end p.c. supplies with remote sense, it’s been awhile and I don’t run one because they were quite expensive, however I do run multiple supplies on both my workstation (680 watt & 500 watt) and its exact duplicate, due primarily to the number and types of connected peripherals AND the randomly occurring problems I encountered when I first assembled them. Took a bit more than most would imagined to do.
FYI; Edison’s first power systems were D.C., if you were next door to the supply your lights were bright, but within a few blocks they were dim & yellow. One mile away there was no glow at all. Lights flickered and changed intensity as the total load (from all connected) on the transmission wires changed. It was actually Tesla who “invented” Alternating Current (A.C.,) and the shunt wound (rotating opposed magnetic field) A.C. motor, which revolutionized the “whole power thing
Steve
