Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,059
Zil's link is not inconsistent with the voltages/currents/pulse rates of the links I found.
Snoobler's paste "1000 watts" is 3x the voltage/current product of the figures I saw for 1 pair of wire, could be larger gauge.
1000 watts, 1 ms would be 1 Joule, low enough to not be safety hazard for humans or ignition for combustibles (but not for an explosive atmosphere.)
Basically, pulses are sent for brief periods, about 1 ms. That is short enough to not be a human safety hazard, so long as they are stopped after detecting incorrect impedance. That provides ground-fault protection as well as if the human is across the leads, something GFCI can't detect.
If voltage and joules delivered were excessive, a 1 ms pulse would be long enough to blow something apart, but a few hundred volts is OK.
The voltage is too high for insulation in LAN cable, beyond what it is rated for. But, the repeated tests of impedance would detect breakdown so circuit could be shut off. It would provide some degree of arc-fault protection as well.
The key for this to work is a controlled impedance of the receiver, so any other loads can be distinguished. Having sloppy control there would allow larger faults to go undetected.
Where I've worked, any shock not due to normal static (shuffling feet over a carpet) was a reportable incident. If something like this gave a 1 ms 300V shock to a person handling RJ-45 plug with sweaty fingers, that would be unacceptable.
I once interviewed with a company bringing out dimmable lights powered by LAN cable. I pointed out that at allowed voltages/currents, it couldn't deliver the watts they planned for. Never heard back from them, eventually got an aerospace job instead. (2008/2009, it was a slow time for employment. 1000 applications, 6 interviews, 1 offer)
Snoobler's paste "1000 watts" is 3x the voltage/current product of the figures I saw for 1 pair of wire, could be larger gauge.
1000 watts, 1 ms would be 1 Joule, low enough to not be safety hazard for humans or ignition for combustibles (but not for an explosive atmosphere.)
Basically, pulses are sent for brief periods, about 1 ms. That is short enough to not be a human safety hazard, so long as they are stopped after detecting incorrect impedance. That provides ground-fault protection as well as if the human is across the leads, something GFCI can't detect.
If voltage and joules delivered were excessive, a 1 ms pulse would be long enough to blow something apart, but a few hundred volts is OK.
The voltage is too high for insulation in LAN cable, beyond what it is rated for. But, the repeated tests of impedance would detect breakdown so circuit could be shut off. It would provide some degree of arc-fault protection as well.
The key for this to work is a controlled impedance of the receiver, so any other loads can be distinguished. Having sloppy control there would allow larger faults to go undetected.
Where I've worked, any shock not due to normal static (shuffling feet over a carpet) was a reportable incident. If something like this gave a 1 ms 300V shock to a person handling RJ-45 plug with sweaty fingers, that would be unacceptable.
I once interviewed with a company bringing out dimmable lights powered by LAN cable. I pointed out that at allowed voltages/currents, it couldn't deliver the watts they planned for. Never heard back from them, eventually got an aerospace job instead. (2008/2009, it was a slow time for employment. 1000 applications, 6 interviews, 1 offer)