The Fire Protection Research Foundation (FPRF) has just released a report on Phase I of their project, Evaluation of Electrical Feeder and Branch Circuit Loading.
The last three editions of the NFPA 70: National Electrical Code (NEC) contain requirements reflective of the increased implementation of energy codes at the municipal, state and federal levels of government. These new NEC rules are complementary to requirements in model energy codes that restrict energy usage in certain types of occupancies. One of the major areas of focus in the model energy codes is the lighting load in commercial buildings. The energy codes specify maximum lighting densities for commercial type occupancies on a VA per square foot basis, while the NEC specifies a minimum load per square foot for the same occupancy.
Can the NEC and model energy code requirements be harmonized? The answer to this question is a qualified yes, but in order to make changes to the minimum load allowances in the NEC, there needs to be a solid technical basis to do so. This is where the current FPRF project is headed.
The first phase of this project identifies the different factors involved in this discussion and establishes means by which the collect electrical usage within buildings down to the branch circuit level. Once this data is harvested and analyzed, that information can be used as the technical basis for making or not making changes to current NEC minimum load allotment requirements.
Currently, alternative approaches to the minimum load prescriptive requirements are available through new exceptions that have been added to the NEC. The outcome of feeder and branch circuit load collection data will be used to support more holistic changes to the baseline NEC load calculation requirements.