A New Approach to an Old Problem

An installed VeriSafe - Absence of Voltage Tester in an electrical enclosure.

The shortcomings of permanently installed voltage indicators led Panduit to create a new and innovative product: the VeriSafe – Absence of Voltage Tester.

The Absence of Voltage Tester (AVT) is a relatively new innovation. As we see it, it’s a new approach to an old problem.

Unlike traditional voltage testers, the AVT is not portable. It is installed in the equipment it is testing. An AVT can be used to determine if and when a circuit part is de-energized prior to opening doors and removing covers from electrical equipment. An AVT will automate the functions of handheld voltage testers for this specific task and will display information about the status of voltage inside equipment without exposure to electrical hazards.

AVTs are entirely different in function, and far more comprehensive than voltage indicators. Although they are both permanently mounted devices, voltage indicators merely provide a visual representation when voltage is present, they are not capable of testing for, nor indicating that, a de-energized condition exists. For instance, if a voltage indicator is not illuminated, it may be because the system is de-energized, but it could also be due to a device failure, an installation failure (if the device becomes disconnected from the wiring, it will not detect voltage), or an indicator (e.g., LED) failure. These are some of the reasons permanently installed voltage indicators were never recognized by OSHA as an alternative to the voltmeter test.

The shortcomings of permanently installed voltage indicators helped bring attention to an industry need and led Panduit create a new and innovative product. An AVT now provides a quick and reliable means of verifying the absence of voltage – a big win on safety and time savings for the electrical worker.

AVTs are defined in a new product listing category that was added to UL 1436, the Standard for Outlet Circuit Testers and Similar Indicating Devices, in September 2016. With the addition of these new requirements, products can now be listed and labeled as an absence of voltage tester. AVT listing requirements were brought about by research presented at the 2016 IEEE Electrical Safety Workshop on electrical injuries that occurred while voltage testing. Because there were no installed devices designed specifically to test for the absence of voltage, unique listing requirements for such a product were not addressed by standards for other product categories. Recognizing this, UL set out to define requirements and identify the best place to publish them. Ultimately, UL 1436 was selected because its scope included other installed testers and it could be revised in a timeframe that coincided with the NFPA 70E 2018 revision cycle, which was also considering provisions for AVTs.

Today, the AVT is truly a new approach to an old problem – and, it’s one that enables user to comply with the new requirements for verifying the absence of voltage in the 2018 edition of NFPA 70E.

The Role Packet Loss Plays in IT and OT Network Performance

Nobody likes a bad packet.

Depending on the network architecture, however, IT and OT network managers look at packet loss differently.

The impact of packet loss

Packet loss negatively impacts IT/OT convergence by reducing throughput and increasing latency. IT and OT network managers look at packet loss differently.

Why do these managers have unique reasons for wanting to banish bad packets? Panduit’s “What is the Impact of Packet Loss?” white paper answers this question, by discussing issues both IT and OT managers encounter as they transform their networks to support business success in the IIoT era.

Reduced throughput
IT network managers dislike packet loss because it steals valuable bandwidth, reducing the link’s available throughput. Typical latency of the enterprise network is responsive enough for their applications.

There is an insatiable appetite for more throughput in enterprise networks, however, not to mention the demand from the myriad connected devices in our homes and in our offices.

A corrupted packet reduces throughput when the switch discards the packet, and again when it is re-sent – essentially causing the packet to be sent twice and reducing a network’s available throughput.

Increased latency
OT network managers look at corrupted packets through a different lens. On the factory floor, a network’s latency is more important than bandwidth or throughput.

For example, when a sensor on the factory floor sends a packet to request an action, it needs the response in milliseconds. The corrupted packet cannot deliver the request, and the retransmission delays the decision on the appropriate action to take. This event can be costly.

IT/OT Convergence
According to Craig Resnick, vice president of ARC Advisory Group, “to properly address the issue of minimizing the corruption of packets requires the convergence of IT and OT, both from a networking infrastructure perspective and a human resources perspective. Converged network architectures bring together IT and OT systems that have long remained separate. As a result, IT and OT professionals who previously only oversaw their own individual systems now must also understand the counterpart technologies to, for example, help eliminate corrupted packets.”

To learn more about the impact of packet loss and how to minimize corrupt packets, no matter your network perspective, download Panduit’s “What is the Impact of Packet Loss?” white paper – or subscribe to our blog to receive our complete 4-part series of IoT 101 white papers.