Electrical Load Sizing Calculations

[apeters62]

So, bear with me here, I'm just trying to learn. I'll consult with an electrician as soon as I can find one to actually do the work.
I'm having new service ran to a new shop on my property. Duke Energy's electrical engineer came out and gave me a Load Sizing sheet I need to figure out to determine total kW. I understand how to get kW but I don't understand his graph.
I would think that kW would be determined off of actual amperage pull from a device/appliance but because the sheet lists receptacles I'm thinking it's based on individual receptacle size. In other words, if I had (10) 15-amp receptacles would I be looking at 150A or only 15A if they were all on a single breaker?
For hardwired items like an Air Compressor, again I would think I would need to know actual amperage but the only published information I can find on any device/appliance is the recommended breaker size. In this case 30A at 240V. So I would use those numbers to come up with 7.2kW?
Really, the receptacles thing is the most confusing since it's such an undetermined thing. But I'm sure this is a common thing for an electrician.

 

[u2slow]

A load calc is a very specific recipe that factors in the large loads of a home, plus allowances for square footage. It is not a sum of receptacles or lights.

Code has a large section dedicated to load calculations. You need to know it to do one properly. Or find a website that attempts to simplify the process.

 

[apeters62]

A load calc is a very specific recipe that factors in the large loads of a home, plus allowances for square footage. It is not a sum of receptacles or lights.

Code has a large section dedicated to load calculations. You need to know it to do one properly. Or find a website that attempts to simplify the process.

Thank you, I thought it might be more in depth than face value but the engineer didn't seem to think it should be overly complicated.

 

[wyliesdiesels]

you dont just add up nameplate amps or receptacle amp ratings. its more complicated than that...

mike holt has a simplified load calc spreadsheet but its for residence only. you may be able to find one for a "commercial" building

 

[alfredeneuman]

you dont just add up nameplate amps or receptacle amp ratings. its more complicated than that...

You take 125% of the largest motor's nameplate rating, and all the rest at 100%
General use receptacles are rated @ 180va per outlet.