I am designing a PCB that needs to convert 24V DC to 5V DC @ 8 amps. I would like to use an off-the-shelf converter and virtually everything in that range is an isolated DC-DC converter. Is there any harm in connecting the VOut- to the VIn- and destroying the "isolated" part of the converter (that I do not need in the first place)? I am planning on using a Murata UEI-30W.
I just want to make sure that there is no downside (i.e. power supply blowing up or unstable) if I connect the input and output grounds. The reason the grounds cannot be isolated is that the devices that requires 5V will share a common metal chassis ground with the devices that require 24V. So, there will be no isolation of grounds regardless.