The Importance of Making the Right Connection

RJ45 jacks and modular plugs are vital to the reliability of the entire structured cabling system. Often system designers do not select specific brands but call them out generically, as long as they are standards’ compliant. That may have been fine for low-bandwidth data and voice connectivity but today’s cabling is required to deliver both data and power (PoE) to many integrated systems now being attached to the network. In addition, connectivity to end devices such as wireless access points (WAPs) and security cameras can include performing under extreme conditions, such as longer distances and harsh environments.

Connectors in the structured cabling links and channels have gotten a bad rap as being the weakest link in the system. This is because they are the first and last contacts to the active component and to the end devices. They are placed where the outbound signal strengths are the strongest and inbound signals are the weakest. Pushing PoE through the cabling system in addition to transmitting data, adds performance stresses even more.

At first glance, it’s not easy to tell the difference between a higher performing connector as they all look similar. But they are not. The engineering of the inner connectivity design makes the difference and needs to be recognized. Selecting the right connector becomes a vital component as it now has to maximize the signal strength while minimizing power loss, to increase transmission performance and reliability.

Small, but Powerful

Even though connectors may seem like a small part of the cabling link, they should be designed for improved power handling, which includes reducing power losses in the cabling system. Connectors are the most important interfacing component in the entire transmission. With the increasing power demands of PoE, especially with high PoE up to 100W, there the highest losses are attributed mainly to the cabling type. Unlike the cabling, connector losses do not depend on the length or gauge size, but are contributing factors to the total cabling power transmission losses due to the internal materials.

In addition to the outer housing, the internal components include metal contacts, Printed Circuit Board (PCB), and the Insultation Displacement Contacts (IDC). The biggest factor to connector performance in regards to power is the PCB conductor route types, which vary from manufacturer to manufacturer.

PCB conductors differ in materials, width, thickness and types. Classified as either Microstrip or Stripline conductor route types, the current flow varies, especially when electricity (or PoE) is introduced. In addition, the PCB circuit resistance contributes to the connectivity power loss. Connectors with the microstrip design style conductor are usually copper-based with a wider route area and has shown to be more efficient because of lower resistance and less voltage drop.

What’s Watt?

The total power loss of a connector is referred to as CpL (Connector power Loss), calculated in Watts (W) which includes the Total Route Loss (TRL) which is calculated for the best connectivity for PoE power efficiency. Basically, the lower the CpL, the more efficient the connectivity for PoE power transfer because of a lower internal heat loss.

When comparing the performance with Stripline conductor versus the Microstrip design, the CpL per conductor might be almost negligible per run and may not be noticed immediately, but over time can add up to significant losses. In a recent lab study by Legrand, the TRL using a Stripline style averaged a 56 milliwatt (mW) loss compared to the Microstrip conductor which had a TRL of 7.6mW per jack. This may seem small per jack, but when added up in an enterprise installation, the lower loss contributes to reduced energy usage which also affects operational costs which can be significant depending on the size of the cabling plant and number of connections.

An additional benefit with a more energy efficient connector is the environmental impact. Every little bit to reduce the carbon footprint is a major win for sustainability and preserving the earth. Selecting a connector that allows the least carbon dioxide emissions can add up to saving 1.76kwh per connectivity run.

Meeting Industry Standards

Industry standards have guided system designers to selecting the right cable and connectivity for the installations based on specific performance parameters. ANSI/TIA-568.2-D defines balanced twisted-pair cabling and components for both data and power delivery. TIA’s Technical Bulletin, TSB-184-A specifically provides recommendations of twisted-pair cables that will support the supply of direct-current (DC) power to networked devices. In particular, it aims to minimize the temperature rise in groups or bundles and includes different pathway types, as well. Connectivity guidelines include IPC-2152 which is the standard for determining current-carrying capacity in the PCB.

ISO/IEC 11801-1 is the international standard defining generic cabling and connectivity for customer premises. However, another international standard, IEC 60512-99-001, was created to provide test requirements RJ45 connectors, specifically under PoE capacity loads during connection and disconnection processes. If the connectors pass all the tests, they are deemed compliant which means that their transmission performance is not impacted by the use of PoE, that is, no corrosion appears on the surface of the contact used for transmission. IEC 60512-99-002 was created to address high power, such as in Types 3 & 4. In situations where the IEC 60512-99-00x standard has not been enforced, an electric arc may appear during the disconnection process and can damage and corrode the contact. As a result, the contact may not be able to be used anymore after several disconnections and the connector will need to be replaced. This will drive up maintenance and installation costs.

The Clarity connectivity, which incorporates the Microstrip design, has proven to meet or exceed the recommended optimal rating specifications with an eye on the lowest CpL value to deliver the best performance in PoE connectivity while reducing the energy footprint. Evaluated and verified by ETL, the Legrand connector level (CpL) program earned the Certificate of Conformance, which has been published in report #105180855CRT-001.

The future reliability of networks is a key consideration to standards’ compliancy because passive networks are expensive to upgrade and rapid technology obsolescence is to be avoided, particularly in the buildings’ industry. Each manufacturer varies in material selection used in their RJ45 connectors and plugs. Legrand’s Clarity connectivity product lines are designed to provide one of the highest solutions in PoE efficiency. Backed by 3rd party verification, it’s a mighty win for the smallest, but most powerful component in the cabling system.