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. Anthony – James R. Harvey
University of Michigan, Ann Arbor
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
