Cabling Recommendations for PoE

PoE (Power Over Ethernet) - is a technology that allows a network device (a switch, most likely) to transmit not only the data but also the electrical power to a powered device, for example, to a camera, using Ethernet cable's 8 conductors. That makes the montage much more convenient, and sometimes even necessary, due to the absence of powering cables and devices. Yet, thus, the requirements to ethernet cables are higher. Recommendations from Trassir specialists are the next:

• Category - CAT5e minimum, better - CAT6/7 ;
• Maximum length of a cable - 80 m (one should consider a repeater over this distance);
• 100% Copper conductors. The use of CCA cable (Copper Clad Aluminum) is highly not recommended, especially for PoE;
• Conductor thickness - 0.51 mm (24AWG). Consider 0.47 mm only if not planning to use PoE;
• Conductor resistance - not higher than 9,38 Оm / 100 m ;
• Cable diameter - not less than 3 mm if planned to use on open spaces;
• Conductor isolation material should be resistant to weather conditions if planned to use outdoors, for example - HDPE. For cable isolation - PVC;
• Consider using Field Termination Connectors (tool-free RJ45 (8p8c) connectors) instead of regular ones.

Other recommendations:

• Use manufacturer's junction boxes for cameras to better isolate cable infrastructure from dust and humidity;
• If planned to use PoE splitters to power up remote microphones, always use shielded cables of FTP type;
• Secure CCTV outdoor devices (especially network devices) with appropriate lightning protection, because cables like to conduct electricity from lightning.
• When using lightning protection in systems with PoE, one should take into account the compatibility of protective devices with one or another implementation of the PoE standard (in particular, additional galvanic isolation in a lightning protection device naturally leads to PoE inoperability, as do too low-voltage non-linear protection elements).

Vasily Selivantsev