Ethernet (base T) was designed to be intrinsically safe, connecting two points with cable isolation at both ends. You can cut and hold onto the cables until the cows come home with zero risk. POE slightly changes this as multiple cables may have core centre taps that are common, but still they present no shock risk. None of this is thus the slightest bit relevant to BS7671, although it seems to have become included. Very odd.

I guess you could say the same of SELV lighting, which BS 7671 has covered for a reasonably long time. I guess part of the argument is that BS 7671 covers a lot of things other than just electric shock protection (from causing fires to cable supports to EMC) and in the world of standards it's useful to have a back stop 'if nothing else covers it then refer to this for basic principles'. I do think that 522.6 is ill thought out and badly placed though - insisting on earthing things presumes ADS and really doesn't make a lot of sense for separated or truly double/reinforced insulated systems and possibly not FELV either.

   - Andy.

Ethernet (base T) was designed to be intrinsically safe, connecting two points with cable isolation at both ends. You can cut and hold onto the cables until the cows come home with zero risk. POE slightly changes this as multiple cables may have core centre taps that are common, but still they present no shock risk. None of this is thus the slightest bit relevant to BS7671, although it seems to have become included. Very odd.

I guess you could say the same of SELV lighting, which BS 7671 has covered for a reasonably long time. I guess part of the argument is that BS 7671 covers a lot of things other than just electric shock protection (from causing fires to cable supports to EMC) and in the world of standards it's useful to have a back stop 'if nothing else covers it then refer to this for basic principles'. I do think that 522.6 is ill thought out and badly placed though - insisting on earthing things presumes ADS and really doesn't make a lot of sense for separated or truly double/reinforced insulated systems and possibly not FELV either.

   - Andy.

Again, whilst SELV is designed to be intrinsically safe, some product standards now have deviated from that path, and the assumed safety has been lost. This is NOT an issue between ELV vs LV, or telecomms vs BS 7671 (IEC 60364) ... it's one of product standards not aligning with basic safety principles set out in what are termed 'horizontal standards', quite possibly with scope not fully aligned relative to real-world use-cases.