While ZSI may be an effective way to mitigate risks of injury and damage to electrical equipment in the event of a fault, it must be specified, applied, and installed properly – and thoroughly commissioned. All circuit breakers within the protected zone must be equipped with ZSI capability. ZSI installation depends on proper interconnect wiring between circuit breakers, and often, different switchgear lineups…
Senior commissioning agents Brandon Sedgwick, PE and Jeff Womack of HP&D will join other industry thought leaders at the 5th annual Critical Facilities Summit, taking place October 23-25, 2017 in Minneapolis, MN, to share experiences and lessons learned, and provide an in-depth look at leading trends in the design, management, and operation mission critical environments. Join Brandon as he shares Legends of the Fail from a commissioning agent’s logbook, and Jeff as he explains why Some Like it Hot – Commissioning in a Live Site…
How often is your standardized approach resulting in an over-designed ground grid? Stop wasting your dough by blindly erring on the side of caution simply because you don’t know what lies beneath. While standardizing a ground grid design seems like it would save time and money, this approach fails to consider a site’s soil composition and resistivity. Soil resistivity is affected by variables such as layer composition, moisture, molecular structure, salt content, other chemicals, etc. Making assumptions based merely on a site’s location, visible soil observations, or soil borings is not enough to determine its apparent resistivity. All variables, especially those affecting life-safety, must be incorporated to allow for site-specific considerations…
Last week, I watched a BMS contractor trying to communicate with a Variable Frequency Drive (VFD), but as soon as he tried to control the VFD’s speed, the connection was dropped. Although both the BMS contractor and the VFD contractor tried for a couple of weeks to resolve the issue with their respective tech support groups, nothing they suggested worked…
GE Grid Solutions is discontinuing several relays from its Multilin SR family of products. These microprocessor-based multi-functional relays were widely used around the turn of the century for industrial protection and management applications in industrial environments, data centers, electrical service entrances, distributed generation (DG) interconnects, motors, transformers, and generators. GE announced, “manufacturing of SR750/760, SR469, SR745 and SR 489 will be discontinued on 1st of January 2020 due to the unavailability of critical components used within the product.” Options for customers with affected relays…
On November 15 & 16 of this year, CEATI will host its 8th Annual Grounding and Lightning Conference in Arlington, VA. This open forum is supported by more than 35 participating utilities and facilitates information exchange and networking. The conference brings together leading subject matter experts from around the world, including HP&D’s own Hilton Mills. Hilton will be presenting Grounding Testing Techniques & Troubleshooting, during which he will discuss the fall of potential (FoP) and computer-based test instrument…
Hood Patterson & Dewar (HP&D) invites visitors to explore its new website, which features a responsive design to provide a user-friendly experience for desktop and mobile visitors. With its improved navigation and functionality, the site allows visitors to easily access current information about HP&D’s services. Through a new integrated blog called The Conduit, HP&D will continue to extend additional information to visitors with a range of posts, announcements, technical articles, and case studies. Users also have…
Find it Early An unplanned outage of any kind is intolerable – and expensive. Preventive maintenance of electrical equipment plays a key role in minimizing outages, yet this type of maintenance is often overlooked. Without an effective electrical preventive maintenance program, the risk of serious electrical failure increases. According to IEEE 493-2007 — Recommended Practice for the Design of Reliable Industrial and Commercial Power Systems, electrical equipment deterioration is normal, but left unchecked it can…
Ground Fault Testing: Why It Matters A ground fault occurs when an energized portion of a grounded electrical system becomes unintentionally connected with a path to “ground” or “earth” (through personnel, equipment enclosures, grounded conductors, conduits, fish-tape, etc.). When this happens, the system phase-to-ground voltage can cause harmful and excessive levels of current to flow through the unintentional path. The magnitude of unwanted ground current varies depending on a variety of system conditions. Higher levels…
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