This question has a bit of application background so please bear with me:
I'm working on a LED lighting system. The controller (MCU, led drivers and led supply) will be powered by a single DC switching power supply. The luminaries are the typical aluminum with leds in series PCB attached to a large heatsink and optics. The luminaries will be mounted on cable trays.
The problem is that the DC ground of the led PCBs is intentionally connected to the heatsinks by mounting screws (not my decision not anything I can do about it). In turn, the heatsink is part of the luminary chassis itself and will be in touch with any other metal supporting it, in this case the cable tray. For security reasons, the tray is connected to Protective Earth (as the luminary chassis should be..)
This, once mounted, will make an unintended connection of DC Ground to PE.
So, I'd need any advice in the following:
1) Is this installation viable? I mean, suppose a leak that goes to PE, that could affect DC grounding or even destroy the electronics, am I right?
2) Will this connection create AC noise on the DC Ground?
3) Since this connection will be made unintentionally at the "chassis" of the appliances (heatsinks, trays), should I intentionally make a lowest impedance possible connection of PE to DC Ground at the controller PCB?
This all sounds like a very bad idea, but I'm not 100% sure nor have strong arguments to argue with my boss about this, so any expert advice will be highly appreciated.