Common earth question across devices.

[Nick Barton-Wells]

Hi all,

I think it was Joth who replied to a post I made a few months ago about ensuring a common ground is shared between Loxone extensions located in different cabinets.

In my case, I have a main cabinet in the house and a smaller cabinet in an outbuilding. My understanding was that it makes sense (and is required) to share a common earth / 0V reference between them.

This video has confused me a bit though: https://youtube.com/shorts/6LGUPt1Z2ow?si=HYXhe5j7V38OWsNz

My setup is as follows:

• Loxone Tree is run from the main cabinet
• Tree goes to several RGBW Tree dimmers
• The 24V power supply for the lights themselves is located in a smaller cabinet upstairs
• Tree is fed from the main cabinet, but the 24V for the lights comes from the upstairs PSU

In the video, it’s mentioned that the PSU negative (0V) should be linked back to the main cabinet in the utility room. Is that correct in this scenario, or have I misunderstood it completely?

I just want to make sure I’m not creating issues with floating references or potential communication problems on Tree.

Thanks in advance.
Nick 

[SavvySpaces - Loxone Web Shop]



You need a common 0v reference across all PSU’s

Connecting that Common 0v to earth is a whole other matter. 

Big risks exist where you have multiple Earth connection to the 0v line - fault current will use the path created so if you are going to go down the PELV route make sure you fully understand the risks to equipment in fault scenarios from all other circuits and check the legislation on SELV & PELV.  

On 19 Dec 2025, at 19:55, Nick Barton-Wells <nick....@gmail.com> wrote:



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[Nick Barton-Wells]

Thank you for the clear reply.