Today at the usual hour we review best practice literature for the design, construction and operation of Power-Limited Circuits in healthcare facilities. With our previous tenure on Code Panel 15 of the National Electrical Code (which covers healthcare facilities, primarily) and our recent appointment by IEEE to Code Panel 3 (which covers power limited circuits in all occupancy classes) we set ourselves up to respond to the proposals that will shape the 2029 NEC. Use the login credentials at the upper right of our home page.
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If one imagines that three-phase hospital power distribution systems as “arteries” then power limited circuits can be imagined as the “capillaries” that drive hundreds of end use clinical equipment and devices. The analogy captures the hierarchical, physiological structure of hospital electrical systems—much like the human circulatory system—where power flows from high-capacity trunks to precision, low-risk endpoints.
Three-Phase Systems: The Arteries and Veins
Three-phase hospital power distribution systems function as the arteries and veins: they are the robust, high-volume “vascular” network. Incoming utility power (or on-site generators) arrives as three-phase medium voltage, stepped down through transformers and switchgear into the Essential Electrical System (EES). This backbone—normal power, life-safety, critical, and equipment branches—delivers bulk kilowatts across the facility to major loads: HVAC, lighting, elevators, imaging suites, and operating-room receptacles. Like arteries, these feeders carry large currents over long distances with minimal loss; like veins, they return current safely while maintaining redundancy and selective coordination to keep the “body” (hospital) alive during outages.
Power-Limited Circuits: The Capillaries
Power-limited circuits (NEC Article 725/724 Class 2 and Class 3) are the capillaries. They are the countless, tiny, energy-restricted final branches that directly “perfuse” end-use clinical devices. These circuits are deliberately power-limited—typically ≤30 V and ≤100 VA—to prevent fire, shock, or interference in patient-care spaces. They supply nurse-call systems, bedside monitors, infusion-pump controls, alarm signaling, data links, and low-voltage sensors. Just as capillaries exchange oxygen and nutrients cell-by-cell without flooding tissue, power-limited circuits deliver only the precise, safe wattage needed by sensitive electronics while isolating them from the high-energy main distribution. Their thin insulation, separation rules, and inherent current-limiting transformers mirror the delicate walls of capillaries.
The comparison illuminates why hospitals cannot rely solely on heavy three-phase feeders: without these microscopic “capillaries,” clinical devices would either lack power or be exposed to dangerous fault energies. The analogy shows how the entire system maintains life—bulk transport for infrastructure, micro-delivery for patient care—while enforcing safety through progressive limitation. In essence, the capillaries make the circulatory system functional at the point of use.
Sie strahlt vor Freude über ihre Auszeichnung – TH-Alumna Melanie Klaus. Für ihre Bachelorarbeit im Bereich Erneuerbare Energien wurde sie vom Solarenergieförderverein Bayern geehrt. In ihrer Bachelorarbeit im Studiengang Elektro- und Informationstechnik untersuchte sie das Zusammenspiel von Wind- und Solarenergie und den Nutzen, der sich hieraus für die regenerative Energieerzeugung erzielen lässt. Untersucht wurde also die Nutzung der natürlichen Kombination von Wind und Sonne für die Energieerzeugung. Um die Rentabilität dieser Einspeisekombination zu ermitteln, hat Melanie Klaus ein Software-Tool entwickelt, welches zur Planung und Simulation abgestimmter Photovoltaik-Wind-Kombinationen dient und bereits für die Errichtung einer Photovoltaik-Anlage zu einem Windpark eingesetzt wird.
Starting 2023 we separated our coverage of solar energy standards from our standing Electrical and Energy colloquia and placed emphasis on seasonal life cycle returns. We start with the following titles
International Code Council Section 1607 Photovoltaic panels or modules
ASHRAE International: 90.1 Building Energy Code & 189.1 Green Energy Code
Time permitting: Example design specification and construction contract.
Other standards developers and publishers are also present in this domain but this list is where we will start given that we only have an hour. Join us today at 16:00 with the login credentials at the upper right of our home page.
The Commission voted on a series of mostly consent agenda items focused on electric reliability, market rules, compliance, infrastructure, and related matters. Some of them are relevant to large, sometimes privatized, campus power systems:
Major initiative to accelerate large-load interconnections. The Commission’s headline action was the issuance of six “show cause” orders directing every jurisdictional RTO/ISO (except Texas/ERCOT) to justify or reform how they connect very large electric loads, particularly AI data centers. The objective is to reduce delays while protecting grid reliability and ensuring that costs are appropriately assigned.
Large customers expected to bear infrastructure costs. FERC made clear that new large loads should generally pay for the transmission and distribution upgrades needed to serve them, rather than shifting those costs onto existing retail customers. This principle is expected to influence future tariff filings nationwide
Encouragement of customer-owned generation. The Commission encouraged tariff structures that would allow large customers to supply some or all of their own electricity—such as on-site generation, microgrids, or other behind-the-meter resources—to reduce impacts on the bulk power system.
MISO emergency demand-resource improvements. The Commission conditionally accepted tariff revisions from MISO that improve the visibility, dispatch, and operation of demand-side resources during grid emergencies beginning with the 2028–2029 planning year. This strengthens reliability during extreme system conditions.
A clear policy shift toward speed-to-power. The June meeting signaled perhaps the strongest policy emphasis in years on rapidly connecting new electric demand while maintaining reliability. The Commission characterized the integration of very large loads—especially AI-related facilities—as a national priority and indicated that existing interconnection practices may no longer be adequate
For universities, research campuses, hospitals, semiconductor manufacturers, and data center developers, the June 2026 meeting represents a significant shift in federal policy. Rather than treating large-load requests as exceptional cases, FERC is moving toward standardized, faster interconnection procedures coupled with clearer cost-allocation rules. Institutions planning major campus expansions or new energy-intensive facilities should monitor the forthcoming tariff revisions from their regional transmission organizations, as these changes could substantially affect project schedules, interconnection costs, and opportunities to incorporate on-site generation or microgrids.
Key Reliability & Cybersecurity Actions. FERC approved important updates to Critical Infrastructure Protection (CIP) Reliability Standards. These included modernized rules for virtualization (allowing secure use of virtual machines), enhanced security management controls for low-impact cyber systems (CIP-003-11), and refinements to the definition of “control center” to better protect high-risk assets. The changes aim to strengthen the bulk-power system against rising cyber threats and extreme weather while reducing unnecessary administrative burdens.
Electric Rate and Complaint Resolutions. The Commission resolved several long-running rate complaints, including setting a base return on equity (ROE) of 9.57% for New England Transmission Owners. It addressed complaints involving spot market sales exceeding price caps in the WECC region and cost allocation issues in MISO related to DOE emergency orders. Several tariff revisions and generator interconnection filings were also accepted.
Other Actions. FERC modernized Electric Quarterly Report (EQR) filing requirements, authorized multiple asset transactions and dispositions, and approved several natural gas pipeline, storage, and abandonment projects. A presentation on the 2025 State of the Markets Report was also delivered.
FERC’s involvement in CHP plants at universities and hospitals depends on and how the facility interacts with the bulk electric power system and wholesale markets. In many cases, FERC’s role is indirect—but it can become significant under certain conditions. We cover this topic separately in our periodic US Department of Energy Combined Heat & Power eCATALOG
Next Open Meeting: May 21. Keep in mind that much “bandwidth” is devoted to administrative issues; the technical specifics of primary interest to us referenced in case dockets that are referenced here: FERC Online
The current full complement of five FERC commissioners is relatively new as of December 23, 2025. The two most recent additions — Chairman Laura V. Swett (term expiring June 30, 2030) and Commissioner David A. LaCerte (term expiring June 30, 2026) — were confirmed by the U.S. Senate on October 7, 2025.
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This restored FERC to its full five members after prior vacancies and transitions earlier in the year. The other commissioners (David Rosner, Lindsay S. See, and Judy W. Chang) have been in place since mid-2024 or earlier, but the current lineup only fully formed about two and a half months ago.
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This followed changes tied to the new administration, including shifts in majority and leadership.
January 22. Issues of interest discussed at the FERC Open Meeting on January 22, 2026, centered primarily on electric sector matters related to generator interconnection reforms, expedited processes for resource adequacy. Our interest lies in the effect of FERC action will have on the utility costs of educational settlements which, of course, practically involves all utilities and how those decisions are reflected in state tariffs.
One issue of particular interest for Michigan: Midcontinent Independent System Operator, Inc. (MISO) Expedited Resource Addition Study (ERAS) process (Docket No. ER25-2454-002): The Commission addressed arguments on rehearing and sustained its prior July 21, 2025, order approving MISO’s ERAS framework. This provides an expedited interconnection study process for generation projects addressing urgent near-term resource adequacy and reliability needs in the MISO region. Discussions involved balancing reliability concerns (e.g., load growth, resource shortfalls) against claims of undue discrimination or preference in interconnection queuing, as raised by public interest groups. We will see these conclusions reflected in Michigan Public Service Commission action.Other agenda elements likely included routine administrative matters (e.g., A-1 Agency Administrative Matters, A-2 Customer Matters/Reliability/Security/Market Operations) and consent items (often non-controversial electric, gas, hydro, or certificate matters voted en bloc without discussion).
No major presentations were noted, and the meeting focused on these reliability/interconnection and market integrity issues amid broader grid challenges like queue backlogs, rapid load growth, and transitioning resources.The Q&A afterward involved energy media, with emphasis by Laura V. Swett on reliability concerns ahead of likely winter storms. The next public open meeting is scheduled for Thursday, February 19th.
December 18. The public meetings are dominated by administrative procedures and mutual admiration. Technical issues that require in-depth, expert-level understanding of complex laws, rules, guidelines, and precedents beyond surface-level awareness appear deeper into the FERC website. There you will generally find:
Nuanced interpretation of statutes and agency decisions
Awareness of historical context and evolving policies
Insight into how rules interact with technical, economic, and operational realities
Impacts of changes and navigate compliance strategically
As interest and time allows we can pick through technical specifics regarding FERC oversight of interstate electricity with the IEEE colleagues.
Here we shift our perspective 120 degrees to understand the point of view of the Producer interest in the American national standards system (See ANSI Essential Requirements). The title of this post draws from the location of US and European headquarters. We list proposals by a successful electrical manufacturer for discussion during today’s colloquium:
2026 National Electrical Code
CMP-1: short circuit current ratings, connections with copper cladded aluminum conductors, maintenance to be provided by OEM, field markings
CMP-2: reconditioned equipment, receptacles in accessory buildings, GFCI & AFCI protection, outlet placement generally, outlets for outdoor HVAC equipment(1)
(1) Here we would argue that if a pad mount HVAC unit needs service with tools that need AC power once every 5-10 years then the dedicated branch circuit is not needed. Many campuses have on-site, full-time staff that can service outdoor pad mounted HVAC equipment without needing a nearby outlet. One crew — two electricians — will run about $2500 per day to do anything on campus.
CMP-3: No proposals
CMP-4: solar voltaic systems (1)
(1) Seems reasonable – spillover outdoor night time lighting effect upon solar panel charging should be identified.
CMP-5: Administrative changes only
CMP-6: No proposals
CMP-7: Distinction between “repair” and “servicing”
CMP-10: Short circuit ratings, service disconnect, disconnect for meters, transformer secondary conductor, secondary conductor taps, surge protective devices, disconnecting means generally, spliced and tap conductors, more metering safety, 1200 ampere threshold for arc reduction technology, reconditioned surge equipment shall not be permitted, switchboard short circuit ratings
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Salutariness (Cleanliness) standards follow culture (which follows the science which follows water and chemical management systems). What is considered clean or hygienic in one culture may differ from what is considered clean or hygienic in another culture. In some cultures, it is customary to remove shoes before entering a home, as it is considered unclean to wear shoes indoors. In Japan, it is customary to take a bath or shower before entering a public bathhouse or hot spring, as it is considered unclean to enter a communal bath without washing first. Most public swimming pools in the United States conform to a similar standard.
In some cultures, it is customary to eat with one’s hands, while in others, using utensils is the norm. Similarly, in some cultures, it is customary to clean one’s hands and face before eating, while in others, it is not considered necessary. Cleanliness standards can also vary depending on the level of economic development, access to clean water and sanitation facilities, and public health policies in different countries. Mahatma Gandhi believed that promoting cleanliness and hygiene could help in building a strong and self-sufficient nation.
“Harlem school custodian to retire, gets cafeteria dedicated to him” | Rockford Register Star
During today’s colloquium we review best practice literature for hygiene in education community interior spaces; including related accessory technologies. Owing to the circumstances of the pandemic we have rewritten our past coverage of this topic for 2022.
Among the standards setting organizations active in this domain: (Short List)
We place public consultation deadlines at top priority in the time available and will schedule a separate break-out session to write and send comments.
Open to everyone. Use the login credentials at the upper right of our home page.
On Friday this group Facetimed me. This is their yearly get together. They tell me that they “are connected for life.” When you commit to something bigger than yourself you don’t just give yourself a better chance to win, the bonds you build are for life. pic.twitter.com/mSc4BECrb3
Sydnee Sinn, Sarah Forsyth, Olivia Millen and Kate Stewart-Barnett run 8:33.40 in the 4x800m relay to break the school record at Penn Relays!🟢⚪ pic.twitter.com/y6VQFJVrMT
— MSU Track & Field/Cross Country (@MSU_TFXC) April 25, 2026
Riley Gaines is a beautiful example of the joy of motherhood.
From championing women’s sports to working out women with her daughter, Margot, she shows how motherhood deepens purpose and fills life with unmatched love.
📣 NSAI is seeking new members for our standards committees
We are establishing new technical committees on Light Gauge Steel, Mass Engineered Timber, and the National Annex for Eurocode 5 (structural fire design).
Once was fun, twice is very nice! UVM Olympian Ben Ogden has done it again, capturing silver in the men’s cross-country team sprint w/teammate Gus Schumacher! This is the first medal for Team USA in this event and makes Ogden the team’s most decorated men’s cross-country skier. https://t.co/0SxTfMnKQI
✅ SCHOOL RECORD
✅ NCAA RECORD (by 8 seconds btw)
✅ 10TH FASTEST 5000M BY AN AMERICAN
✅ 11TH INDOOR 5000M TIME IN THE WORLD
✅ FIRST COLLEGIATE WOMAN TO RUN SUB 14:50 (indoor AND outdoor)
CHASE DOWN❗️ Şilan Ayyildiz finishes 9th individually at the cross country national championship to lead the Ducks to a 3rd place finish. Ayyildiz went from 18th to 9th place over the final K 😮💨 #GoDuckspic.twitter.com/spP7A0UEmo
Yale topped previously undefeated Harvard in the 141st playing of The Game, earning a share of the Ivy League title and the league’s first-ever automatic bid to the NCAA FCS playoffs.
BYU’s Jane Hedengren just beat the defending 5K and 10K national champion by 42 seconds head-to-head at regionals. FORTY-TWO SECONDS! We are witnessing greatness. 🏃♀️ pic.twitter.com/6ELw3anmhL
Led by senior Chad Perrine and junior Luke Skuratowicz, three Hope College men’s cross country runners finished in the Top 30 of the 167-runner field at the Muskegon Community College Jayhawk Invitational on Saturday. Read the meet recap on the Hope Athletics website. #d3xcpic.twitter.com/Dynob8mVrX
Northwest High School junior Cooper Lutkenhaus has run the fastest 800-meter race in the world for any athlete younger than 18! Cooper set the new U18 world best at the USA Track & Field Outdoor Championships by running a time of 1:42.27 to earn silver. pic.twitter.com/5imZ9yZHLN
The U.S. men’s four won gold for the first time at the U23 World Championships. Ryan Martin, Wilson Morton, Sam Sullivan, and Lyle Donovan are victorious in the A Final, winning by 2.25 seconds. pic.twitter.com/2fAtSEwewA
Over the weekend, Anhelina Khmil earned a second place finish at the CEV Nations Cup Final in Portugal as part of the Ukrainian team! pic.twitter.com/2zuEa9wk9c
The bottom of the ground was nothing for Emily Beisel! She moves into the Top 4 of her set by almost two tenths of a second to lock in her place at the Cheyenne Frontier Days Semifinals. pic.twitter.com/1uDeztOlZM
— The Cowboy Channel (@Cowboy_Channel) July 20, 2025
Savannah Sutherland d capped an incredible career at Michigan with her second NCAA title and has been named the 2024-25 Female Michigan Athlete of the Year! 〽️ #LeadersAndBest
— Michigan Track & Field / Cross Country (@UMichTrack) June 23, 2025
𝐀𝐔𝐁𝐔𝐑𝐍 𝐁𝐄𝐈𝐍𝐆 𝐀𝐔𝐁𝐔𝐑𝐍
Our list of Fences Riders of the Year is getting long…
✔️ 2025: Avery Glynn (SEC & NCEA ROTY); Kate Hagerty (SEC Freshman ROTY)
✔️ 7-straight SEC ROTY awards
✔️ 4 of the last 7 NCEA ROTY honors
✔️ 7 SEC Freshman ROTY awards#WarEaglepic.twitter.com/1bRaWk4ytY
Savannah Sutherland sets the Hodges Stadium facility record and for the second straight year she sets the NCAA East First Round record in the 400H! pic.twitter.com/u48jsKv3Zm
— Michigan Track & Field / Cross Country (@UMichTrack) June 1, 2025
Your Duke family is proud of you guys! Dom and Gavin both fared well in the state tournament!! Dom went 2-2, and Gavin went 7-1! Gavin finished 3rd overall in his weight class!! Congratulations to both boys!! @WEVSD_sports@whsladydukes@AndyPeltzpic.twitter.com/5yEMNYkU7Q
Another @MSU_Hockey BIG10 Championship! What an exciting night at Munn Arena for our Spartan players, coaches, students and fans. Go Green!! pic.twitter.com/u9ZWUTeBVc
Every Thursday, coach Brandon runs men’s IM threshold practice and Coach Sarah & I run the women’s IM group. It’s one of those “all hands on deck” type of day. Last night, in the 400 IM the men went 1-2-3-5-10-11 and the women went 2-3-4-5-6-10-17-22. pic.twitter.com/pCfhLWSvoA
What a shot at the buzzer! Michigan State pulls off the win at Maryland, 58-55. #Spartans have won four games in a row, including three straight against ranked opponents.pic.twitter.com/1NMM6xdH46
Great day in the weight room at Weatherford High School! We have football, basketball, girls and boys track programs working hard. We are blessed with the best facilities in the state! pic.twitter.com/gvH85GZmoM
The Revere Varsity Competition Squad traveled to Big Walnut High School today to compete in the OASSA State of Ohio Cheerleading Championships! They finished in fourth place, D3 Non Build Division!!! We are so proud of you ladies! @RevereLocalpic.twitter.com/evF06thfAD
Wow! What an amazing couple of weeks for ‘OE’ Justin Davies. He broke the Welsh indoor 800m record at the Keely Klassic and then went on to become the British champion at the UK Indoor Championships! #uptherose 🌟🏅 pic.twitter.com/fgFq5AOX09
— Sport & PE | King Edward’s School (@KESBathSport) February 24, 2025
My girl shot her first ever perfect 5 bullseyes at her county tournament today
Great job girl! pic.twitter.com/Xhyl1bEK0R
“We’re putting every school receiving taxpayer dollars on notice that if you let men take over women’s sports teams or invade your locker rooms, you will be investigated for violations of Title IX and risk your federal funding.” –President Donald J. Trump 🇺🇸 pic.twitter.com/MUd6FAetWr
Remember when it was so cold the rivers and lakes iced over? Our college wild swimmers certainly do – they took the plunge (without wetsuit insulation) and lived to report back! 🥶 pic.twitter.com/CKyLK0ySMu
“We’re feeling confident in our performance so far. We’re being challenged, but so far have managed to stay sharp.” – Catherine Clifford, third
This quote sums up the Canadian women’s performance thus far at the World University Games, as they remain undefeated after two wins on… pic.twitter.com/jetQK1TtbH
“Rowing is more poetry than sport.” — George Pocock (‘Boys in the Boat’ 2024), a British-born boat builder, rowing coach, and influential figure in American rowing, best known for his craftsmanship of racing shells and his philosophical approach to the sport.
New update alert! The 2022 update to the Trademark Assignment Dataset is now available online. Find 1.29 million trademark assignments, involving 2.28 million unique trademark properties issued by the USPTO between March 1952 and January 2023: https://t.co/njrDAbSpwBpic.twitter.com/GkAXrHoQ9T
