What is the demand factor allowed for calculating the neutral conductor size for an electric range load according to the NEC®?

The demand factor for calculating the neutral conductor size for an electric range load, according to the NEC, is based on the understanding of how the loads are utilized within a typical residential or commercial setting. In this specific case, the demand factor of 70% is applied when determining the neutral size for an electric range load. This is due to the characteristic of electric ranges where not all elements will be in use simultaneously at full load.

Using a demand factor allows for a more efficient and cost-effective sizing of conductors, reflecting actual usage patterns rather than just the maximum potential load. This ensures that the installed conductors are adequate for the expected load while avoiding oversized conductors that could lead to unnecessary material costs and labor.

Understanding this demand factor is crucial for electrical designers and installers as it helps ensure that the installation meets safety and performance standards while adhering to the NEC guidelines.