Great experiment, Jhunter! Re, remarks regarding "cable disturbing" etc. Just came across a professional catalogue on equipment & installations destined to electricians issued by Legrand, a french electrical equipment multinational.
Samples of advice for "...when installing cabling... particularly conducting inconsistent loads, or powering inconsistent circuits especially ones with variations in the frequencies carried (audio, voice, voice & data)..."
*ensure that cables running in parallel are physically 15cm apart regardless of insulation quality
*do not bend the cables abruptly (energy loss in low voltage situations!). Rather, create space for large diametre turns and hide the cables appropriately.
*If you encounter temporary cable overlapping, ensure 90 degrees cross at the cables meeting point.
*At very low voltages with high frequency variation, measure losses before final installation. Use SSTP cables or any other balanced conductor specially designed for such applications.
*Ensure all connections are according to norm and connectors used... withstand weather and pollution conditions. If in doubt, or measured losses are high, try direct connection with end appliance without external connector.
*For dependable readings, allow the installation to reach an electrical "balance situation". Make sure you connect a proxy load at reception end asap if the installation is uni-directional. Allow your system to repose at least 1 hr. with a load while you continue other work. Readings will not be reliable unless the installation reaches this balance! Do not allow variations of more than 5% in readings within the same 30 mins!
*Measure airbound losses -- if exposed cables do not give steady reading, switch the meter to "save" and physically move the exposed part of the cables. Differences of more than 7% may mean re-installation! Please consult our technical dep'timmediately before removing the installation!
All I'm saying after this long blurb (thanks for the hospitality Jhunter & all) is: industrial application are doing some of the things we heatedly debate!
For me, voodoo because I can hardly understand the intro to a physics handbook let alone install industrial norm cabling. For others, all in a day's work!
I mean, there must be *some* resident EEs at Legrand, ABB, motorola, etc, surely. What if EEs wrote this stuff?
How come they don't post here?
Samples of advice for "...when installing cabling... particularly conducting inconsistent loads, or powering inconsistent circuits especially ones with variations in the frequencies carried (audio, voice, voice & data)..."
*ensure that cables running in parallel are physically 15cm apart regardless of insulation quality
*do not bend the cables abruptly (energy loss in low voltage situations!). Rather, create space for large diametre turns and hide the cables appropriately.
*If you encounter temporary cable overlapping, ensure 90 degrees cross at the cables meeting point.
*At very low voltages with high frequency variation, measure losses before final installation. Use SSTP cables or any other balanced conductor specially designed for such applications.
*Ensure all connections are according to norm and connectors used... withstand weather and pollution conditions. If in doubt, or measured losses are high, try direct connection with end appliance without external connector.
*For dependable readings, allow the installation to reach an electrical "balance situation". Make sure you connect a proxy load at reception end asap if the installation is uni-directional. Allow your system to repose at least 1 hr. with a load while you continue other work. Readings will not be reliable unless the installation reaches this balance! Do not allow variations of more than 5% in readings within the same 30 mins!
*Measure airbound losses -- if exposed cables do not give steady reading, switch the meter to "save" and physically move the exposed part of the cables. Differences of more than 7% may mean re-installation! Please consult our technical dep'timmediately before removing the installation!
All I'm saying after this long blurb (thanks for the hospitality Jhunter & all) is: industrial application are doing some of the things we heatedly debate!
For me, voodoo because I can hardly understand the intro to a physics handbook let alone install industrial norm cabling. For others, all in a day's work!
I mean, there must be *some* resident EEs at Legrand, ABB, motorola, etc, surely. What if EEs wrote this stuff?
How come they don't post here?