Ethernet has signals of a couple of volts peak to peak at the transmitter end, falling to about half that at the far end for the fastest sequence of 10101 that s supported, lower frequencies, such as 11001100 experience less loss. The idea that regs requiring an RCD apply to this would be  a disaster waiting to happen.

Power over ethenet rides a current limited Dc between the two earth references of the line pairs on which the data is imposed, and in some designs on unused pairs as well. The normal power ADS considerations are not really suitable. I suggest that B7671 is the wrong standard, and those relating to network cabling are more suited.

PSTN should be installed as per the BT SNs unless there is a good reason to deviate

Mke

Ethernet has signals of a couple of volts peak to peak at the transmitter end, falling to about half that at the far end for the fastest sequence of 10101 that s supported, lower frequencies, such as 11001100 experience less loss. The idea that regs requiring an RCD apply to this would be  a disaster waiting to happen.

Power over ethenet rides a current limited Dc between the two earth references of the line pairs on which the data is imposed, and in some designs on unused pairs as well. The normal power ADS considerations are not really suitable. I suggest that B7671 is the wrong standard, and those relating to network cabling are more suited.

PSTN should be installed as per the BT SNs unless there is a good reason to deviate

Mke

110.1.2 (vii) specifically includes this in scope.

Also, BS EN 50174-2 has HD 60364 as a normative reference.

mapj1 said:

Ethernet has signals of a couple of volts peak to peak at the transmitter end, falling to about half that at the far end for the fastest sequence of 10101 that s supported, lower frequencies, such as 11001100 experience less loss. The idea that regs requiring an RCD apply to this would be  a disaster waiting to happen.

Power over ethenet rides a current limited Dc between the two earth references of the line pairs on which the data is imposed, and in some designs on unused pairs as well. The normal power ADS considerations are not really suitable. I suggest that B7671 is the wrong standard, and those relating to network cabling are more suited.

Agreed ... but whilst the source of those signals or voltages under BS EN 60950-1 used to be SELV/PELV, now that has been replaced by BS EN 62368 series, which doesn't have the equivalent of SELV and PELV,, it becomes more tricky.

That doesn't mean every product is not safe nor not compliant, but how is that demonstrated now? More to the point, are there products out there that are not equivalent to SELV/PELV?

And of course, an RCD is not feasible for that type of signal - neither, at present, could it be done for pure DC regardless of whether it's LV or ELV.