Load Calculations

D

dvcraven052256

Member
Location
St. Louis, missouri
Occupation
Electrical Engineer
I would like to get some input relative my load calculations for attached panel schedule. In essence this panel is for normal power for 29 story hotel high-rise dwelling. All units are provided for via 208/120V bus duct. The attached panel schedule is for all normal power for the infrastructure of the building. I am most interested in the DF as applied.

I have contacted the mechanical engineer and said I could use 90% demand for HVAC and equipment. The HVAC consist of VAV w/reheat, water source heat pumps, electric wall heat, & electric unit heaters.

I am basing my OCPD for MHDP at 2000/3P from the total estimated demand.

Your thought as most welcome. Thanks

Dan Craven
 

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It's not clear how you did your calcs and demand percentages, however, assuming your calcs for each load classification are correct, you would need a MINIMUM of 2311A switchboard for your design as it is calculated load and how code requires you to size the equipment. I would go with 2500A or even 3000A for future load. Then again I could be misinterpreting but it's only one sheet to go off. Where did you get the demand factor percentages in your lower table?
 
Could you also provide some insight on your heating / air conditioning load calculations and demand factor? You should only be taking the higher between the two. See NEC 220.60.

I don't think you need to put both in the calculation. They can not be run at the same time and taking the higher of the two should suffice.
 
You should really go through 220 and make sure you're doing all your calcs properly. The mechanical engineer should not be giving you anything other than electrical requirements of the units they are providing (i.e. voltage, HP/kVA). You should be using the code to determine the demand factors.
 
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