Which loads are typically used as fixed appliance loads in dwelling calculations?

Which loads are typically used as fixed appliance loads in dwelling calculations?

• A. Water heater - 4000 VA at 240V; Electric range - 6000 W
• B. Dishwasher - 1300 VA at 120V
• C. Sump pump - 864 VA
• D. Attic fan - 1176 VA at 120V

Answer: (A)

Fixed appliance loads are the large, permanently installed devices whose maximum demand is used in sizing the service. Water heaters and electric ranges fit this category because they are high-wattage, typically on dedicated circuits, and their demand is predictable and substantial for planning the service capacity. In residential load calculations, including these as fixed loads ensures the service is sized to handle their combined draw even when other loads vary. Other devices like a dishwasher, sump pump, or attic fan are smaller or more intermittent and are usually treated as general appliance or lighting/receptacle loads with appropriate demand factors rather than fixed loads. For example, a water heater around 4,000 VA plus a 6,000 W range sums to about 10,000 VA of fixed load, which is why this pair is used as fixed loads. The others aren’t placed in the fixed-load category.

Fixed appliance loads are the large, permanently installed devices whose maximum demand is used in sizing the service. Water heaters and electric ranges fit this category because they are high-wattage, typically on dedicated circuits, and their demand is predictable and substantial for planning the service capacity. In residential load calculations, including these as fixed loads ensures the service is sized to handle their combined draw even when other loads vary. Other devices like a dishwasher, sump pump, or attic fan are smaller or more intermittent and are usually treated as general appliance or lighting/receptacle loads with appropriate demand factors rather than fixed loads. For example, a water heater around 4,000 VA plus a 6,000 W range sums to about 10,000 VA of fixed load, which is why this pair is used as fixed loads. The others aren’t placed in the fixed-load category.