agermeyer
Member
- Location
- Pittsburgh, Pennsylvania
I could use a little clarification on how to make sure I am teaching my students this calculation right. When calculating the connected load of a school, before applying the derating, should you still apply the 125% for any continuous loads? As an example a 30,000 sq. ft. school with 700 amps of lighting at 120 V, 100 receptacles, and 50,000 VA of A/C. Without the 125% the calculation would be
84,000 VA + 18,000 VA + 50,000 VA = 152,000 VA / 30,000 = 5.06 VA/ft. sq.
1st 3 VA @ 100% * 30,000 + 2.06 VA * 30,000@ 75% = 136,350 Demand
If you calculate the lighting or receptacles or any loads at 125% then the final answer will be higher.
Do you still take 125% of the largest motor also while figuring out the total connected load?
84,000 VA + 18,000 VA + 50,000 VA = 152,000 VA / 30,000 = 5.06 VA/ft. sq.
1st 3 VA @ 100% * 30,000 + 2.06 VA * 30,000@ 75% = 136,350 Demand
If you calculate the lighting or receptacles or any loads at 125% then the final answer will be higher.
Do you still take 125% of the largest motor also while figuring out the total connected load?