Demand VS Connected. What to use?

Timona

Member
Location
Houston, Texas
Occupation
Graduate Electrical Design Engineer
I am doing total load calculation of a building in Excel.
I am using the numbers from the panel schedules.

Now, what should I be using from the panel schedules? The demand load or the connected load?
 

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Update: My boss chewed me up and said it was demand. So, I had to revise my excel spreadsheet. It didn't take me long though.
 
I've always shown total connected load on utility load letters. The utility company will use their own data and calculations of what they think the demand load will be. Typically much much lower. For your clients sake, and your design as well, I'd only give them the connected which is what you should be designing around as well.
 
For NJ, the utilities typically only want to see one final number so you have to pick between demand and connected.

I would say give them whatever numbers you used to size your main service equipment, I use the demand load, but I know some people use connected. Like others have said, I once had a utility in PA send me their demand calculations (I wish I had saved it) and they take 60% of your HVAC load, and some low % for the lighting loads based on your building type.

Demand loads are already probably double whatever the meter will read and the connected load is even higher than that. They utility has a better handle on how much actual load each building/building types are using since they have the data to run the statistical analysis on it.
 
Use the load calculations in the nec. It will be less than the so called connected load, but two or three times what the typical real load will be in most cases.
 
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