[G6Tanuki]

The commercial supplies I used to work with [typically 24V@40A] had the DC output floating, but with strapping-options on the output terminals so you could - if needed - link one side of the output to station ground.

This sometimes caused issues with the 'remote sense' on the regulator which could get to 'see' stray circulating currents in the negative wiring.

Equally, quite a bit of gear I've worked on have the regulator-transistors for the PSU implemented so the cases [collectors] of the transistors are grounded and the regulator operates on the negative side - this avoids the need for insulating washers between the heatsink and the series-pass transistors but does mean that the 'negative' side of the smoothing-capacitor-stack and the transformer windings sit at a variable voltage above station ground which can lead to fault-diagnostic difficulties when done by someone unfamiliar with the idea.