deee
Member
- Location
- Freeport Texas
These steps "1 through 8" are what I follow when doing load calculations. The question at the bottom of the page is one that I run across that doesn't seem to fit into my steps here. Step #4 and Step #7. Maybe someone can tell me if they apply or they don't and why.
What is the computed load for a store room with the following? 2300 sq/ft of floor area.70 receptacles, 15 ft of show window, a 24 amp 3phase air conditioner, a120 volt 1500 watt water heater. The service is a 120/208 wye.
Computed Load Calculations for Store Room
- General Lighting Loads (sq/ft area) 220.12 Use Table 220.12 to calculate minimum light load and 220.15(a) says to use demand factor of 125% for calculating minimum calculated load.
- Receptacles 220.14 says to use 220.14(I) to calculate the receptacle loads at 180va each. 220.44 allows the demand factors of Table 220.44
- Show Window Lighting if used.220.14(G)(2) Says 200va per 1ft and 220.44(A) says 200va per linear foot; However 220.44(B) is considering Tract Lighting and has 150va per sq/ft added if used. 210.19(A)(1)(a) says to use the demand of 125% for continuous loads. Generally Lighting loads are considered continuous in commercial applications.
- Combine the General lighting Loads 220.42 says to use the demand factors of Table 220.42
- Water Heater or Specific Appliance, if used. 220.14(A) says for a specific appliance use the nameplate current rating.
- Motor Loads. "ACs are considered Hermetic." 220.50 says to use 430.24, 430.25, 430.26 and for hermetic refrigerant motor compressors use 440.6(A) which states the name plate current ratting shall be used.
- Outside Sign and Lighting. (Only if used on a TEST.) 220.14(F) says to calculate a minimum of 1200va for required branch circuit specified by 600.5. 600.5(A) states "Each commercial building and each commercial occupancy accessible to pedestrians shall be provided with at least one outlet in an accessible location at each entrance to each tenant space for sign and outline lighting system use."
- Combine the loads and divide by the voltage (multiply the voltage by 1.732 for 3 phase to get the corrected voltage) to get the computed load.
What is the computed load for a store room with the following? 2300 sq/ft of floor area.70 receptacles, 15 ft of show window, a 24 amp 3phase air conditioner, a120 volt 1500 watt water heater. The service is a 120/208 wye.