ICC Residential Electrical Inspectors Practice Exam

For a single-family dwelling with air conditioning rated at 6000 VA and fixed electric space heating rated at 10,800 VA, what is the minimum calculated demand load?

1. 7,500 VA

2. 10,000 VA

3. 10,800 VA

4. 12,000 VA

The correct answer is: 10,800 VA

To determine the minimum calculated demand load for the single-family dwelling with the given parameters, it's essential to apply the principles of demand calculations as outlined in the National Electrical Code (NEC) and related guidelines for residential loads. In this scenario, you have air conditioning rated at 6,000 VA and fixed electric space heating rated at 10,800 VA. When calculating the demand load for residential buildings, particularly when both air conditioning and heating are involved, there are specific methods for combining these loads. Typically, for dwelling units, the NEC allows for a demand factor to be applied to both heating and cooling loads. Electric space heating loads are usually treated at their full value since they are generally used simultaneously during periods of extreme cold, while cooling loads may have a demand factor applied. To arrive at the minimum calculated demand load in this case: 1. Start with the electric space heating load: 10,800 VA. Since this load is considered fully utilized, it is taken in full without any demand adjustment. 2. For the air conditioning load, however, typically a demand factor can be applied if it does not overlap with the heating peak. In many cases, if the air conditioning is sized properly, it is reasonable to apply a demand