A feeder or service neutral load can be figured at what percentage of the load on the ungrounded conductors for ranges and ovens?

When calculating the feeder or service neutral load for ranges and ovens, the National Electrical Code (NEC) allows the use of a 70 percent factor on the load of the ungrounded conductors. This percentage accounts for the typical usage and demand characteristics of these appliances, recognizing that they do not usually draw their full load continuously.

In practice, this means that when determining the size of the neutral conductor in a residential service or feeder, you can safely calculate it based on 70 percent of the total load from the ungrounded conductors. This is particularly useful as it can help in reducing the size of the neutral conductor, thus saving on material costs and space in the electrical system without compromising safety.

Additionally, employing this percentage supports efficient load balancing without overloading the neutral, which is crucial in multi-circuit applications. This approach also demonstrates an understanding of demand factors in residential wiring, leading to more efficient design and operation of electrical systems.