Tag Archives: D2

Loading
loading..

Solar Panels on King’s College Chapel Roof

“…The solar panels will populate the gothic chapel roof, producing an approximate 105,000 kWh of energy a year – enough to run the chapel’s electricity, and saving around £20,000 in energy bills per year. The college confirmed that any excess energy would be sold off to the national grid.

King’s College Announcement

Solar Panels on King’s College Chapel Roof

Solar panels perform better when listening to music:

A 2013 study by researchers at Imperial College London and Queen Mary University of London showed that solar panels actually work better when exposed to music, of multiple genres. Scientists at the university proved that when exposed to high pitched sounds, like those found in rock and pop music, the solar cells’ power output increased by up to 40 percent. Classical music was also found to increase the solar cells’ energy production, but slightly less so than rock and pop, as it generally plays at a lower pitch than pop and rock. Whether they know it or not, British band Coldplay are just one of the artists benefitting from this research. During their 2021 tour, they installed solar photovoltaic panels in the build-up to each show, “behind the stage, around the stadium and where possible in the outer concourses”…

BS 7671 Requirements for Electrical Installations

The Major Differences in Electrical Standards Between the U.S. and Europe

Representative Calculation: (WAG)

To determine how much electrical power and lighting 12 kilowatts (kW) will provide for an educational facility, we need to consider the following factors:

    1. Power Distribution: How the 12 kW will be distributed across different electrical needs such as lighting, computers, HVAC (heating, ventilation, and air conditioning), and other equipment.
    2. Lighting Requirements: The specific lighting requirements per square foot or room, which can vary based on the type of facility (classrooms, libraries, laboratories, etc.).
    3. Efficiency of Lighting: The type of lighting used (e.g., LED, fluorescent, incandescent) as this affects the power consumption and lighting output.

We start with lighting.

    1. Lighting Efficiency:
      • LED lights are highly efficient, typically around 100 lumens per watt.
      • Fluorescent lights are less efficient, around 60-70 lumens per watt.
    2. Lighting Power Calculation:
      • 12 kW (12,000 watts) of LED lighting at 100 lumens per watt would provide: 12,000 watts×100 lumens/watt=1,200,000 lumens
    3. Illumination Requirements:
      • Classroom: Approximately 300-500 lux (lumens per square meter).
      • Library or laboratory: Approximately 500-750 lux.
    4. Area Coverage:
      • If we target 500 lux (which is 500 lumens per square meter), we can calculate the area covered by the lighting: (1,200,000 lumens)/ 500 lux=2,400 square meters

Now we need to allocate power to other loads.

    1. Lighting: Assuming 50% of the 12 kW goes to lighting:
      • Lighting Power: 6 kW (6,000 watts)
      • Using the previous calculation: 6,000 watts×100 lumens/watt=600,000 lumens
      • Area Coverage for lighting (at 500 lux): (600,000 lumens)/500 lux=1,200 square meters
    2. Other Electrical Needs:
      • Computers and equipment: Typically, a computer lab might use around 100 watts per computer.
      • HVAC: This can vary widely, but let’s assume 4 kW is allocated for HVAC and other systems.

Breakdown:

    • Lighting: 6 kW
    • Computers/Equipment: 2 kW (e.g., 20 computers at 100 watts each)
    • HVAC and other systems: 4 kW

Summary

    • Lighting: 12 kW can provide efficient LED lighting for approximately 1,200 square meters at 500 lux.
    • General Use: When distributed, 12 kW can cover lighting, a computer lab with 20 computers, and basic HVAC needs for a small to medium-sized educational facility.

The exact capacity will vary based on specific facility needs and equipment efficiency.

 

 

Electric Vehicle Power Transfer

2023 National Electrical CodeCurrent Issues and Recent Research

 

2026 National Electrical Code Workspace


August 5, 2021

The 2020 National Electrical Code (NEC) contains significant revisions to Article 625 Electric Vehicle Power Transfer Systems.  Free access to this information is linked below:

2023 National Electrical Code

2020 National Electrical Code

You will need to set up a (free) account to view Article 625 or you may join our colloquium today.

Public input for the 2023 Edition of the NEC has already been received.  The work of the assigned committee — Code Making Panel 12 — is linked below:

NFPA 70_A2022_NEC_P12_FD_PIReport_rev

Mighty spirited debate.   Wireless charging from in-ground facilities employing magnetic resonance are noteworthy.  Other Relevant Articles:

  • Article 240: Overcurrent Protection: This article includes requirements for overcurrent protection devices that could be relevant for EV charging systems.
  • Article 210: Branch Circuits: General requirements for branch circuits, which can include circuits dedicated to EVSE.
  • Article 220: Load Calculations: Guidelines for calculating the electrical load for EVSE installations.
  • Article 230: Services: General requirements for electrical service installations, which can be relevant for EVSE.
  • Article 250: Grounding and Bonding: Requirements for grounding and bonding, which are critical for safety in EVSE installations.

 

Technical committees meet November – January to respond.   In the intervening time it is helpful  break down the ideas that were in play last cycle.  The links below provide the access point:

Public Input Report Panel 12

Public Comment Report Panel 12

Panel 12 Final Ballot

We find a fair amount of administrative and harmonization action; fairly common in any revision cycle.   We have taken an interest in a few specific concepts that track in academic research construction industry literature:

  • Correlation with Underwriters Laboratory product standards
  • Bi-Directional Charging & Demand Response
  • Connection to interactive power sources

As a wiring safety installation code — with a large installer and inspection constituency — the NEC is usually the starting point for designing the power chain to electric vehicles.   There is close coupling between the NEC and product conformance organizations identified by NIST as Nationally Recognized Testing Laboratories; the subject of a separate post.

Edison electric vehicle | National Park Service, US Department of the Interior

After the First Draft is released June 28th public comment is receivable until August 19th.

We typically do not duplicate the work of the 10’s of thousands of National Electrical Code instructors who will be fanning out across the nation to host training sessions for electrical professionals whose license requires mandatory continuing education.  That space has been a crowded space for decades.   Instead we co-host “transcript reading” sessions with the IEEE Education & Healthcare Facilities Committee to sort through specifics of the 2020 NEC and to develop some of the ideas that ran through 2020 proposals but did not make it to final ballot and which we are likely to see on the docket of the 2023 NEC revision.   That committee meets online 4 times monthly.  We also include Article 625 on the standing agenda of our Mobility colloquium; open to everyone.   See our CALENDAR for the next online meeting

Issue: [16-102]

Category: Electrical, Transportation & Parking, Energy

Colleagues: Mike Anthony, Jim Harvey

Workspace / NFPA


More

U.S. NATIONAL ELECTRIC VEHICLE SAFETY STANDARDS SUMMIT | DETROIT, MICHIGAN 2010

Gallery: Electric Vehicle Fire Risk

 

Illumination 300

IEEE Education & Healthcare Facilities Committee

“Starry Night Over the Rhône” 1888 Vincent van Gogh

Today we refresh our understanding of the moment in illumination technologies for outdoor lighting systems— related but different from our exploration of building interior illumination systems in Illumination 200.  Later in 2023 we will roll out Illumination 500 which explores litigation related to public illumination technology.  As cities-within-cities the shared perimeter of a campus with the host municipality has proven rich in legal controversy and action.

Illumination technology was the original inspiration for the electric utility industry; providing night-time security and transforming every sector of every economy on earth.  Lighting load remains the largest component of any building’s electric load — about 35 percent– making it a large target for energy regulations.

Our inquiry begins with selections from the following documents…

International Electrotechnical Commission TC 34 Lighting

IEC 60364 Electrical Installations in Buildings

2023 National Electrical Safety Code

IEEE P3001.9 – Recommended Practice for the Design of Power Systems Supplying Lighting Systems in Commercial and Industrial Facilities

Institution of Engineering and Technology: Recommendations for Energy-efficient Exterior Lighting Systems

2023 National Electrical Code: Article 410  (While the bulk of the NEC concerns indoor wiring fire hazards, there are passages that inform outdoor lighting wiring safety)

2019 ASHRAE 90.1: Chapter 9 Lighting

Illumination Engineering Society: Various titles

ISO/TC 274 Light and lighting

Salt Water River Project: Outdoor Lighting Standards

US DOE-EERE Building Energy Codes Program

…and about 20 other accredited, consortia or ad hoc standards developers and publishers aligned principally with vertical incumbents.  Illumination was the original inspiration (i.e. the first “killer app”) for the electrical power industry in every nation.  Its best practice literature reflects a fast-moving, shape-changing domain.

Click in today with the login credentials at the upper right of our home page.

Upper Wharfedale Primary Federation School District Yorkshire Dales

McGill University: Before electricity, streets were filled with gas lights

Outdoor lighting systems can be owned and maintained by different entities depending on the context and location. Here are some examples of ownership regimes for outdoor lighting systems:

  1. Public ownership: In this case, outdoor lighting systems are owned and maintained by the local government or municipal authority. The lighting may be installed in public spaces such as parks, streets, and other outdoor areas for the safety and convenience of the public.
  2. Private ownership: Outdoor lighting systems may be owned by private individuals or organizations. For example, a business owner may install outdoor lighting for security or aesthetic reasons, or a homeowner may install outdoor lighting in their garden or yard.
  3. Co-owned: Outdoor lighting systems may be owned jointly by multiple entities. For example, a residential community may jointly own and maintain outdoor lighting in their shared spaces such as parking areas, community parks, or recreational facilities.
  4. Utility ownership: Outdoor lighting systems may be owned and maintained by utility companies such as electric or energy companies. These companies may install and maintain street lights or other lighting systems for the public good.
  5. Third-party ownership: In some cases, a third-party entity may own and maintain outdoor lighting systems on behalf of a public or private entity. For example, a lighting contractor may install and maintain lighting in a public park on behalf of a local government.

The ownership regime of an outdoor lighting system can have implications for issues such as installation, maintenance, and cost-sharing. It is important to consider ownership when designing and implementing outdoor lighting systems to ensure their long-term effectiveness and sustainability.

More

International Commission on Illumination

National Electrical Manufacturers Association

National Electrical Contractors Association

Representative Specifications

Sam Houston State University | Division 26500 Interior and Exterior Lighting

University of Delaware | Division 265100 Interior Lighting

Cal Poly University San Luis Obispo | Division 265100 Interior Lighting

Relevant Research

Enhancing the Sustainability of Outdoor Floodlighting for Cultural Heritage Buildings

The Performance and Impact of LED Floodlights in an Outdoor Electrical Substation During Misty Weather Conditions

Replacement of HPS Luminaires with LED Luminaires for the Lighting Requirements of an Outdoor Electrical Substation

 

A Procedure to Estimate the Energy Requirements for Lighting

 

A Procedure to Estimate the Energy Requirements for Lighting

Giuseppe Parise – Luigi Martirano – Luigi Parise

Sapienza, University of Rome

Abstract:  The amount of the electrical energy used for the interior lighting of medium and large buildings is generally considerable. The European Standard EN15193 was devised to establish conventions and procedures for the estimation of energy requirements of lighting in buildings by an energy performance numeric indicator. This methodology is based on the three derating factors that consider the influence of the daylight exploitation, the occupancy behavior and, if present, of a constant illuminance sensor. The factors are evaluated by a statistical approach on the basis of general reference data tabulated by the same Standard, not considering more detailed parameters of the control system that can impact severely in the effective energy savings. The Standard methodology appears extremely useful for a preliminary evaluation. For a more accurate evaluation, this paper suggests an improvement of the procedure that considers the effective operation time and occupancy behavior, the type of control and lamps, the number of control groups, the technique of modulation (dimming or switching), and the delay in turning off. The suggested procedure is compared with the Standard one to highlight the improvements.

CLICK HERE to order complete paper

Related:

Energy performance of interior lighting systems

Energy performance of buildings: An useful procedure to estimate the impact of the lighting control systems

Topology of Continuous Availability for LED Lighting Systems

Solar Photovoltaic Energy Systems

Technical Committee 82 of the International Electrotechnical Commission is charged with preparing international standards for the full length of the solar energy power chain  The span of the power chain includes the light input, the cell itself, and the fittings and accessories to the end use (utilization) equipment.

Strategic Business Plan of IEC Technical Committee 82

The United States is the Global Secretariat for TC 82 through the US National Committee of the International Electrotechnical Commission (USNA/IEC) administered by the American National Standards Institute(ANSI).  Standards Michigan is a long-standing member of ANSI since our “standards journey” began at the University of Michigan in 1993.

The USNA/IEC and participates in its standards development processes; typically collaborating with global research and application engineers in the IEEE Industrial Applications Society and the IEEE Power and Energy Society.   To advance its agenda for lower #TotalCostofOwnership for US real asset executives and facility managers Standards Michigan also collaborates closely with subject matter experts who contribute to, and draw from, the knowledge base in the IEEE Education and Healthcare Facilities Committee (E&H).

The IEC permits public commenting on its draft standards; though you will need to establish login credentials:

IEC Public Commenting

Your comments will be reviewed by the IEC National Committee of the country you live in, which can decide to propose them as national input for the final draft of the IEC International Standard.  This approach makes it easier for individual nations to participate in IEC standards development processes because the resources that national standards bodies need to administer participation resides in Geneva and is managed there.  

“The Eclipse of the Sun in Venice, July 6, 1842” | Ippolito Caffi

We collaborate with the IEEE Education & Healthcare Facilities Committee which has its own platform to tracking commenting opportunities:

IEEE E&H/USNC/IEC Workspace

As of this posting, no interoperability redlines have been released for public consultation.   In large measure, IEC titles contribute to a level playing field among multi-national electrical equipment manufacturers so we should not be surprised that there are no redlines to review.   When they are released we place them on the agenda of the IEEE E&H Committee which meets 4 times monthly in European and American time zones.

Log in to the E&H Committee meeting

Issue: [18-240]

Category: Electrical Power, Energy Conservation

Contact: Mike Anthony, Jim Harvey, Peter Sutherland


LEARN MORE:

[1] US Commenters must route their comments through the USNA/IEC.

[2] Many product and installation standards are developed by the Association of Electrical Equipment and Medical Imaging Manufacturers (NEMA): CLICK HERE

[3]  NEMA comparison of NEC and IEC electrical safety standards

Dutch Institute for Fundamental Energy Research

 

 

Interoperability of Distributed Energy Resources

IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems is effectively the global standard for interconnection of distributed resources with large scale electric power systems.  It provides requirements relevant to the performance, operation, testing, safety, and maintenance of the interconnection.  Apart from the power reliability and sustainability zietgeist we have seen in campus bulk power distribution systems, this title is usually referenced in research projects undertaken in university research enterprises.  The standard is intended to be universally adoptable, technology-neutral, and cover distributed resources as large 10 MVA.  To wit:

IEEE 1547-2018 Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces: This standard — emerging from IEEE Root Project 1547.3 — 2007 asserts first principles for improved performance for distributed energy resources, connected to the grid. NIST funding aided this standard’s development.   Links to related titles, recently released for public consultation, are listed below:

P1547.2/D6.5, August 2023 – IEEE Approved Draft Application Guide for IEEE Std 1547™, IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems

1547.3 Guide for Cybersecurity of DER Interconnected with Electric Power Systems | Comments due May 27

Guide to Using IEEE Standard 1547 for Interconnection of Energy Storage Distributed Energy Resources | Comments Due May 6th

We collaborate with the IEEE Education & Healthcare Facilities Committee on this an related titles.   This committee’s meetings are held 4 times monthly in European and American time zones.  International Electrical Technical Commission titles are items on the standing agenda; a few representative titles are listed in addition to IEEE titles below:

IEC 62746-10-1:2018 Systems Interface Between Customer Energy Management System and the Power Management System – Part 10-1: Open Automated Demand Response: This standard specifies how to implement a two-way signaling system, between utilities and customers, thus allowing utilities to adjust the grid’s load, based on demand. NIST’s David Holmberg and Steve Bushby presented research to the International Electrotechnical Commission (IEC), aiding this US standard’s acceptance as an international one.

IEC 62746-10-3:2018, Systems Interface Between Customer Energy Management System and the Power Management System – Part 10-3: Open Automated Demand Response – Adapting Smart Grid User Interfaces to the IEC Common Information Model: Related to the previous standard, IEC 62746-10-3:2018 defines the interfaces, as well as, the messaging for this two-way signaling system. NIST’s Holmberg and Bushby also facilitated this international standard’s acceptance.

IEEE 21451-001-2017 Recommended Practice for Signal Treatment Applied to Smart Transducers: This guide supports the ability to uniformly processing and classifying data from sensors and actuators in a smart system. The standard enables a common interpretation of data and grid interoperability. NIST personnel served on this standard’s working group, providing NIST research on sensors and actuators.

IEEE 2030.7-2017 Standard for the Specification of Microgrid Controllers: This standard established requirements for controllers, used to sense and manage microgrids. These requirements inform the manufacturing of controllers, and ultimately enable grid interoperability. NIST funding aided this standard’s development.

IEEE 2030.8 Standard for Testing Microgrid Controllers: This testing standard helps verify that microgrid controllers meet these requirements, and, thus, will work as intended. NIST funding aided this standard’s development.

IEEE 1547-2018 Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces: This standard ushers in a new era of improved performance for distributed energy resources, connected to the grid. NIST funding aided this standard’s development.

To inform a United States position on IEC titles we follow the lead of the USNA/IEC whose activity we also track in the IEEE E&H Committee

Issue: [11-17]

Category: Electric, Energy

Colleagues: Mike Anthony, Bob Arno, Neal Dowling, Peter Sutherland

Standards Coordinating Committee Membership

Microgrids

 

Energy Standard for Data Centers

Public consultation on draft changes to the purpose of this standard closes November 17th.

2024 Update to ASHRAE Position Statements

List of Titles, Scopes and Purposes of the ASHRAE Catalog

Public Review Draft Standards

The parent title of this standard is ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings  and is continually under revision; frequently appearing in electrical engineering design guidelines, construction specifications, commissioning and O&M titles in our industry and others.

ASHRAE 90.4 defines an alternate compliance path, specific to data centers, while the compliance requirements for “non-data center” components are contained in ASHRAE 90.1 .  The 90.4 structure also streamlines the ongoing maintenance process as well ensures that Standards 90.1 and 90.4 stay in their respective lanes to avoid any overlap and redundancies relating to the technical and administrative boundaries.  Updates to ASHRAE 90.1 will still include the alternate compliance path defined in ASHRAE 90.4. Conversely the 2022 Edition of 90.4-2022 refers to ASHRAE 90.1-2022; cross-referencing one another synchronously

Links to noteworthy coverage from expert agencies on the 2022 revisions:

Addendum g modifies Sections 3 and 6 to support the regulation of process heat and process ventilation

HPC Data Center Cooling Design Considerations

ASHRAE standard 90.4 updates emphasize green energy

ASHRAE updated its standard for data centers

How to Design a Data Center Cooling System for ASHRAE 90.4

Designing a Data Center with Computer Software Modeling

This title resides on the standing agenda of our Infotech 400 colloquium; hosted several times per year and as close coupled with the annual meetings of ASHRAE International as possible.  Technical committees generally meet during these meetings make decisions about the ASHRAE catalog.  The next all committee conference will be hosted January 20-24, 2024 in Chicago.  As always we encourage education industry facility managers, energy conservation workgroups and sustainability professionals to participate directly in the ASHRAE consensus standard development process.  It is one of the better facilities out there.

Start at ASHRAE’s public commenting facility:

Online Standards Actions & Public Review Drafts

Energy Standard for *Sites* and Buildings


Update: May 30, 2023

Proposed Addendum g makes changes to definitions were modified in section 3 and mandatory language in Section 6 to support the regulation of process heat and process ventilation was moved in the section for clarity. Other changes are added based on comments from the first public review including changes to informative notes.

Consultation closes June 4th


Update: February 10, 2023

The most actively managed consensus standard for data center energy supply operating in education communities (and most others) is not published by the IEEE but rather by ASHRAE International — ASHRAE 90.4 Energy Standard for Data Centers (2019).  It is not required to be a free access title although anyone may participate in its development.   It is copyrighted and ready for purchase but, for our purpose here, we need only examine its scope and purpose.   A superceded version of 90.4 is available in the link below:

Third ISC Public Review Draft (January 2016)

Noteworthy: The heavy dependence on IEEE power chain standards as seen in the Appendix and Chapter 8.  Recent errata are linked below:

https://www.ashrae.org/file%20library/technical%20resources/standards%20and%20guidelines/standards%20errata/standards/90.4-2016errata-5-31-2018-.pdf

https://www.ashrae.org/file%20library/technical%20resources/standards%20and%20guidelines/standards%20errata/standards/90.4-2019errata-3-23-2021-.pdf

We provide the foregoing links for a deeper dive “into the weeds”.  Another addendum has been released for consultation; largely administrative:

ASHRAE 90.4 | Pages 60-61 | Consultation closes January 15, 2023.

It is likely that the technical committee charged with updating this standard are already at work preparing an updated version that will supercede the 2019 Edition.  CLICK HERE for a listing of Project Committee Interim Meetings.

We maintain many titles from the ASHRAE catalog on the standing agenda of our Mechanical, Energy 200/400, Data and Cloud teleconferences.   See our CALENDAR for the next online meeting; open to everyone.


Originally posted Summer 2020.

 

ASHRAE International has released four new addenda to its energy conservation consensus document ASHRAE 90.4-2016 Energy Standard for Data Centers.  This document establishes the minimum energy efficiency requirements of data centers for design and construction, for the creation of a plan for operation and maintenance and for utilization of on-site or off-site renewable energy resources.

It is a relatively new document more fully explained in an article published by ASHRAE in 2016 (Click here).   The addenda described briefly:

Addendum a  – clarifies existing requirements in Section 6.5 as well as introduce new provisions to encourage heat recovery within data centers.

Addendum b  – clarifies existing requirements in Sections 6 and 11 and to provide guidance for taking credit for renewable energy systems.

Addendum d  – a response to a Request for Interpretation on the 90.4 consideration of DieselRotary UPS Systems (DRUPS) and the corresponding accounting of these systems in the Electrical Loss Component (ELC). In crafting the IC, the committee also identified several marginal changes to 90.4 definitions and passages in Section 8 that would add further clarity to the issue. This addendum contains the proposed changes for that aim as well as other minor changes to correct spelling or text errors, incorporate the latest ELC values into Section 11, and to refresh information in the Normative Reference.

Addendum e adds language to Section 11 intended to clarify how compliance with Standard 90.4 can be achieved through the use of shared systems.

Comments are due September 6th.   Until this deadline you may review the changes and comment upon them by by CLICKING HERE

Universitat de Barcelona

 

Proposed Addendum g

Education facility managers, energy conservation workgroups and sustainability professionals are encouraged to participate directly in the ASHRAE standard development process.   Start at ASHRAE’s public commenting facility:

Online Standards Actions & Public Review Drafts

The ASHRAE catalog is a priority title in our practice.  This title appears on the standing agenda of our Infotech sessions.  See our CALENDAR for the next online meeting; open to everyone.

"One day ladies will take their computers for walks in the park and tell each other, "My little computer said such a funny thing this morning" - Alan Turing

Issue: [12-54]

Category: Telecommunications, Infotech, Energy

Colleagues: Mike Anthony, Robert G. Arno, Neal Dowling, Jim Harvey, Mike Hiler, Robert Schuerger, Larry Spielvogel

Workspace / ASHRAE

 

Rightsizing Electrical Power Systems

Standards Michigan, spun-off in 2016 from the original University of Michigan Business & Finance Operation, has peppered NFPA 70 technical committees writing the 2016-2026 National Electric Code with proposals to reduce the size of building premise feeder infrastructure; accommodating the improvements made in illumination and rotating machinery energy conservation since the 1980’s (variable frequency drives, LED lighting, controls, etc.)

These proposals are routinely voted down in 12-20 member committees representing manufacturers (primarily) though local inspection authorities are complicit in overbuilding electric services because they “bill by the service panel ampere rating”.  In other words, when a municipality can charge a higher inspection fee for a 1200 ampere panel, what incentive is there to support changes to the NEC that takes that inspection fee down to 400 amperes?

The energy conservation that would result from the acceptance of our proposals into the NEC are related to the following: reduced step down transformer sizes, reduced wire and conduit sizes, reduced panelboard sizes, reduced electric room cooling systems — including the HVAC cooling systems and the ceiling plenum sheet metal carrying the waste heat away.   Up to 20 percent energy savings is in play here and all the experts around the table know it.   So much for the economic footprint of the largest non-residential building construction market in the United States — about $120 billion annually.

The market incumbents are complicit in ignoring energy conservation opportunity.  To paraphrase one of Mike Anthony’s colleagues representing electrical equipment manufacturers:

“You’re right Mike, but I am getting paid to vote against you.”

NFPA Electrical Division knows it, too.

University of Michigan

 

Rightsizing Commercial Electrical Power Systems: Review of a New Exception in NEC Section 220.12

Michael A. AnthonyJames R. Harvey

University of Michigan, Ann Arbor

Thomas L. Harman

University of Houston, Clear Lake, Texas

For decades, application of National Electrical Code (NEC) rules for sizing services, feeders and branch circuits has resulted in unused capacity in almost all occupancy classes. US Department of Energy data compiled in 1999 indicates average load on building transformers between 10 and 25 percent. More recent data gathered by the educational facilities industry has verified this claim. Recognizing that aggressive energy codes are driving energy consumption lower, and that larger than necessary transformers create larger than necessary flash hazard, the 2014 NEC will provide an exception in Section 220.12 that will permit designers to reduce transformer kVA ratings and all related components of the power delivery system. This is a conservative, incremental step in the direction of reduced load density that is limited to lighting systems. More study of feeder and branch circuit loading is necessary to inform discussion about circuit design methods in future revisions of the NEC.

CLICK HERE for complete paper

University of Houston

2026 National Electrical Code Workspace

Layout mode
Predefined Skins
Custom Colors
Choose your skin color
Patterns Background
Images Background
Skip to content