I thought some of you might find this an interesting and informative read in relation to Ground/Earth loops, noise and inductance issues with all sorts of stuff, including video and hifi.
Page 56 for about 10 pages are useful info, 99-101 are quite informative, but it is all good stuff.
There is a load of information further on about noise elimination methods and what works and what does not.
It is from Bill Whitlock, President
Jensen Transformers, Inc.
Life Fellow, Audio Engineering Society
Life Senior Member, Institute of Electrical & Electronic Engineers
https://centralindianaaes.files.word...notes-v1-0.pdf
I am sure you can then make educated conclusions as to whether a grounding box will or won't work depending on what you find inside it.