Smart cabling for PoE | Dutch IT channel

A recent study by MarketReportsWorld predicts that the global market for Power Over Ethernet (PoE) devices will be worth USD 2.9 billion by 2027. In 2020, it was USD 2.5 billion. USD. This growth is the result of the rise of the Internet of Things in industrial sectors, commercial buildings and the home. Almost daily, new devices appear on the market that are suitable for PoE use in smart buildings. To support a wide variety of mission-critical applications, all of these devices require power and connectivity.

We have become accustomed to a wide selection of USB accessories, which are connected and equipped with different types of USB connectors. We are also now seeing equipment that uses a switched network connection increasingly combine Ethernet network capabilities with PoE.

The higher voltage that PoE offers compared to USB (48v instead of 5v) allows devices to be powered over longer distances, enabling a variety of applications. The type of cable used determines the maximum current and thus also the maximum power. Today, 90W per connection possible – making PoE a highly deployable, optimized alternative for many applications. Separate power supplies, often supplied with external adapters, are no longer necessary. With 4PPoE, up to 90 watts of electrical power can be achieved – more than three times the previous standard and more than six times the original PoE standard. The use of PoE connections not only reduces the number of sockets needed, but also “adapter waste”. In addition, electrical current can be easily turned on or off and monitored.

Increased PoE power also presents a number of challenges, particularly in terms of heat generation and connectivity, which require careful consideration. Push-in connectors in 230v installations are designed to support the highest possible power levels, and RJ45 connectors in a PoE network require similar consideration. Vibrations and cable patching (especially in IoT applications) should also be considered. This allows you to determine how wires should be connected in the connector to withstand external factors and to guarantee the functionality and safety of the connections.

The temperature in cables increases due to current transfer and wear of contact points in connections. Cables and cable bundles become hot due to the power supply. Material may be damaged and higher attenuation losses may affect data transfer in the local area network. When the contact surfaces become loose, age or corrode, the resistance at the contact points increases. This also has a negative effect on data transmission. A design that takes PoE into account ensures that the cable system can withstand higher temperatures. One of the most important preventive measures is to use shorter connections if necessary. The shorter the cable, the less attenuation loss during data transmission and the greater the available reserves for heating effects.

Another important consideration is damage to the RJ45 connectors from sparks generated when disconnecting under load. This erosion can damage the spring contacts in the RJ45 adapters, which in turn means reduced signal transmission. Whether an RJ45 connector suffers from this depends on the mechanical construction and design of the connections. These characteristics should be considered when selecting a product and specified accordingly. The IEC 60512-99-1/2 standards were developed for this.

Networks are expected to remain operational for more than 15 years, so from both a bandwidth and power point of view, it makes sense to consider what to expect over the next 10 years at a minimum when designing. It is important to consider future power and bandwidth needs when specifying cables and determining which RP (Remote Powering) certification class your infrastructure must meet.

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