16. January 2024

4 Min read

    Contents

      Written by Matthias Gerber

      Market Manager Local Area Networks

      Current via network cables

      Power over Ethernet (PoE) is experiencing a boom. Sales of PoE-capable devices are increasing by 20% annually. It is well known that PoE can also be used to supply modern terminals with power in the LAN. Current and data flow via a single Ethernet network cable. This saves additional electrical wiring for terminal equipment such as WLAN connection points, sensors, surveillance cameras, and many other smart building systems.

      Operators often use the existing installations and patch cords for new PoE applications without testing them first. They think the LAN has always worked perfectly so far, so it can also be used for PoE. Until now, however, it was only about data traffic via the Ethernet Protocol. Thanks to Ethernet, data signals usually find their way to their destination. In the event of transmission problems, the system simply switches back to a slower, less demanding transmission. The sources of the fault remain hidden at first.

      The demands are increasing

      However, the demands on LAN cabling increase when high-speed data transmission and PoE work together with high currents.

      We recommend checking the LAN separately and specifically for the parameter resistance unbalance before permanently using higher PoE categories (4PPoE). This is because PoE needs to have a grip on the resistance unbalance in the entire LAN – transmission channels including patch cords. We would happily provide you with information on the corresponding measurement procedures.

      Read more about the details of the problem of resistance unbalance here.

      This video introduces the topic.

       

      Patch cords whose wires are contacted using IDC technology are better suited for long-term PoE applications in local area networks. They can be used to control resistance unbalance.

       

      Risk: Total failure

      The PowerSafe seal indicates that this cabling product is suitable for use with high-performance PoE.

      The most common risks are associated with patch cords with IPC contacting (IPC = insulation piercing contact). This was confirmed by tests carried out at our laboratory in Wetzikon. Piercing contacts can age quickly and in different ways. Over time, this can lead to the dreaded resistance unbalance and a total failure of data transmission.

      That’s why we firmly believe that patch cords with piercing contacts are unsuitable for PoE transmission over long periods and at higher power levels.

      R&M recommends the use of patch cords with insulation displacement contact (IDC). IDC ensures a permanently stable, low-resistance contact of the copper conductors. As a rule, no resistance unbalance caused by the patch cord occurs over the lifetime of the IDC patch cord.

      Know-how counts with PoE. You can find this at R&M.

      We are the only manufacturer of IDC patch cords and a technology leader in insulation displacement contacting. R&M labels PoE-compatible cabling products with the PowerSafe seal.