Heads up- scanner power supplies.

[Draco]

if you use 2 power supplies to make the positive and negative rails, do it only with supplies that have the output isolated from earth ground, the middle lead can be tied to ground then, this will only work on something that has an isolated output, thankfully most good switch modes are isolated.

[Draco]

i can make a more simplified diagram if needed, the one in the links has output pins that are not needed for just one dual rail system. I just conducted my own tests with identical Cosel R150U-12 switchers, the middle or center tap can be tied directly to ground with out a problem, these supplies i bought as used surplus for 15 bucks each, these babies have a current output of 13 amps, while they are 12 volt they can be turned up or down with in 20% of center, i usually set them at 13.8 or down to 12 for use with a laser