2018 IEEE 1584 – 125 kVA Transformer Exception DELETED!

125 kVA – Going, going, gone! After much speculation about the fate of the 125 kVA transformer “exception”, the 2018 Edition of IEEE 1584 – IEEE Guide for Performing Arc-Flash Hazard Calculations has finally been published and made it official.  The 125 kVA transformer exception has been deleted! In its place is the new language: …

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Medium Voltage Power Systems

Medium Voltage Power Systems Denver*: Live Streaming in 4 Sessions: *Relocated from Denver to your location via live streaming. Registration Deadline: April 10, 2020 (in order to receive training material) A recording of this class will be made available to all registered attendees of the Live Streaming Event. Also, each attendee will receive credit for …

Keeping Skills Current on a Limited Budget

2-Part Series Published: May 2017 By Jim Phillips Part #1 of a 2 Part Series: What if you had been stranded on a deserted island for the past five years? By the time you were rescued, you would have missed the explosion of real-time social media, including Facebook, YouTube and Twitter, mobile marketing trends, as well as …

How Many Arc Flash Labels on Equipment?

Question of the Week Some equipment may have multiple arc flash labels for a variety of reasons. Different operating configurations Equipment is long/large – including busway Equipment has different incident energy for main/feeders such as some switchgear. There may be other reasons as well. This week’s question: What is the greatest number of arc flash …

100A panel with 200A “gutter mounted” main. WTF??

Came across this today while surveying. The original drawing shows this panel with a 100A branch mounted main. Well, someone needed that breaker for another panel and removed it and installed this instead. Not in the photo: 4/0 feeder spliced inside an adjacent panel with #2. #2 goes through wireway to this 200A “gutter mounted” …

Easy way to get a series combo rating – sometimes??? Maybe?

Hi all. As I continue to slog through my list of 104 buildings on campus I need to do studies on I discovered yet another over-dutied situation yesterday. Common scenario, 208Y/120V “service” with 15-ish kA available at the main panel and a 100A MLO branch panel right next to it (very short feeder) with 14-ish …

Underrated/Over dutied panels in an old building…..WWYD?

We’ll call this a hypothetical question. Say you are running a short circuit and arc flash study on a 50 year old building as part of a multi-building study. You discover you have about a half dozen branch panelboards that are over-dutied in this building. These are all 225A rated, 208Y/120V. Some are flush in …

Using the series rating charts – real example

Don’t mean to beat this topic to death. Well, yeah, I guess I do, but since I had another example of being over dutied/under rated come up today I thought I would share it. Scenario: Fairly low impedance (2.9%) 300 kva dry transformer originally feeding a large dimmer rack. Over the years someone added a …

Circuit Breaker Maintenance

Apologizes if this topic is covered elsewhere in the forum. If so, please point me in the right direction. We are having some arc flash studies completed for buildings across our campus. The consultant is recommending that fuses be replaced with current limiting type fuses and also that breaker settings be dialed down to be …

Fiber Optic Arc Flash Detection Modeling

I will start by stating that I am not 100% familiar with these types of systems [Fiber Optic Light Detecting]. In recent MV switchgear submittal the manufacturer [I assume at the recommendation of the engineer of record and or the owner] included a fiber optic light detection system for arc flash mitigation. This included “point …

Protective Relaying – Part 2

Protective Relaying – Part 1 and Part 2 Jim Phillips, P.E. will show you how to work with protective relays and determine optimal settings for protection and coordination in this first part of a two part class.  The Class begins with the basics of overcurrent relays and progresses in Part 2 with more advanced topics including …

Protective Relaying

Protective Relaying – Part 1 and Part 2 Jim Phillips, P.E. will show you how to work with protective relays and determine optimal settings for protection and coordination in this first part of a two part class.  The Class begins with the basics of overcurrent relays and progresses in Part 2 with more advanced topics including …

Protective Device Coordination Analysis

Synopsis Protective Device Coordination Analysis is designed to show you how to use time current curves and perform coordination studies with breakers, relays and fuses. The program provides an explanation of how to maximize reliability by developing a properly coordinated power distribution system. Description COORDINATION STUDIES Selective Coordination Basics, Time Current Curves, Data Requirements, Device …

Electrical Power System Engineering

Electrical Power System Engineering Register 3 People and the 4th is FREE! This course by Jim Phillips, P.E. has become the industry standard that defines the “Crash Course” in electrical power systems. People from all seven continents (Antarctica included) have attended this week long program that combines five of Jim’s most popular classes including Power …

Power Distribution Equipment – Part 1

Synopsis: Power Distribution Equipment will help the student gain insight into the operation, selection and application of motors and variable frequency drives. You will also learn about transformer design, application and protection as well as transformer vault requirements. Description Introduction to Specification and Design Design Process, Specifications, Drawings Conductors for General Wiring Ampacity and Temperature …

National Electrical Code – 2017

2017 National Electrical Code  Register 3 and the 4th is FREE! This 2 Day class by Jim Phillips, P.E. covers the major articles found in the 2017 edition of the   National Electrical Code®.  You will not only learn what the various code articles  mean, but you will also learn how to correctly apply the code …

Medium Voltage Power Systems – Part 2

Synopsis The backbone of many electric power systems is the medium voltage distribution system. Typically operating at voltages ranging from 2,400 to 34,500 Volts, voltage stress, corona, surges and protection of equipment all create unique challenges in design, equipment selection, operation and engineering. This 2nd class by Jim Phillips, P.E. takes you through the fundamentals …

Design of Electric Power Systems – Part 2

Synopsis: When it comes to designing an electric power system, the NEC® is just the minimum. This is the second part of a 2 day program to show you how to design and electrical system using the NEC but also how to go beyond the code. When and why do you need to oversize neutrals? …

Coordination and NEC 240.87

NEC 240.87 has addressed a potentially hazardous situation beginning with the 2011 edition. When selective coordination is critical, e.g., minimizing the extent of an outage, a common design practice is to use a main circuit breaker without an instantaneous tripping function and feeder breakers with one. Without an instantaneous, the main can time delay up to 30 …