The minimum size service disconnect for a single-family dwelling with a computed load of 10 kVA is ___ amps.

The minimum size service disconnect for a single-family dwelling with a computed load of 10 kVA is ___ amps.

• A. 30
• B. 50
• C. 100
• D. 60

Answer: (C)

The main idea is how the service disconnect is sized for a dwelling. For single-family homes, electrical code sets a minimum rating for the service disconnect at 100 amperes, regardless of the computed load. Here, the computed load is 10 kVA, which is about 41.7 amperes at 240 volts—below 100 A. Because of the dwelling minimum, the service disconnect must be rated at 100 A. This provides headroom for future growth and keeps the service equipment consistently sized for residential use. If the calculated load ever exceeds 100 A, you’d size the disconnect to meet or exceed that load, but you never go below 100 A for a dwelling.

The main idea is how the service disconnect is sized for a dwelling. For single-family homes, electrical code sets a minimum rating for the service disconnect at 100 amperes, regardless of the computed load. Here, the computed load is 10 kVA, which is about 41.7 amperes at 240 volts—below 100 A. Because of the dwelling minimum, the service disconnect must be rated at 100 A. This provides headroom for future growth and keeps the service equipment consistently sized for residential use. If the calculated load ever exceeds 100 A, you’d size the disconnect to meet or exceed that load, but you never go below 100 A for a dwelling.