Evaluation of Electrical Feeder and Branch Circuit Loading: Phase 1

Great job!!! Hopefully it will serve as a basis (in conjunction with Phase II) to update the current demand loads used in the NEC for commercial buildings and consequently the corresponding sizing of service and feeders and associated raceways. I believe that the same criteria employed in the above study could be extended for the Residential sector (in a future Phase 3), mainly for hi-rise multifamily buildings, where there is a lot of demand factors used for the calculation of service and feeders sizing. Just a couple of suggestions 6.2.1, Table 21: “Traditional Engineering Demand Factors for Building Loads”. Actually this Table includes some loads where the term “Demand Factors” is correctly applicable and others where this term is not applicable. For example: • For “Lighting”, the 1.25 factor is not a “demand factor”, rather it´s a circuit ampacity factor. Different is the case relative to Table 220.42 of the NEC where for some occupancies, there is a demand factor applicable to lighting loads. • Likewise, the figures shown for “Motors” and “Largest Motor” are not demand factors. Rather, they are factors for determining the allowable circuit ampacity. • The same criteria is applicable to “Other loads”. • With respect to “Receptacle”, the demand factors are correct. In the Comments column, the NEC has a requirement for the calculation of the receptacle loads for Banks and Office Buildings, according to 220.14(K) 6.2.2, Branch Circuit Sizing and Protection It’s worth to note that circuit breakers rated 800A and higher (mainly applicable to service and feeders) have the option to specify 100% continuously loaded, which could result in big savings due to the use of lower size conductors and associated raceways.