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Demonstrated Load vs Load Calculation

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It seems to me that Load Calculations for sizing electrical panels are very conservative. I did a quick calculation for my home as it is today and came up with a load calculation of 213 Amps. Over my 200 Amp service. Oops.

I do have a smart meter and it shows a maximum load of 18.721 kW which at 240 volts works out to be 78 amps. A whole lot lower than 213 for sure. That's quite a big difference from the calculated load.

My Daughter has 100 amp service and judging by Load Calculations adding a 14-50 with 40 amp beaker would require a panel upgrade. Her home calculates at 95 amps load as it stands today. Comparing her home to mine I have many more loads than she does (I have two EVSE's for two EV's) but I would (theoretically) be fine with 100 amp service if my peak is 78 amps right? . Is it possible to measure actual load to establish safety of adding an EVSE to a 100amp panel, she doesn't have a smart meter with max load like ours. Or will codes always require a theoretical load calculation vs demonstrated load?
 
There are at least two accepted ways of doing a load calculation. Maybe if you put out what numbers/math you used, we could have a go at it.

You are definitely allowed to go get the nameplate rating for heavy loads, so if you oven is on a 40 amp breaker but it says clearly it can never take more than N kilowatts, you can use the lower number. Same for AC and hot water heater, and dryer...
 
You can also use special devices to ensure that your new load (EV charging) is not coincident with other loads. For example, there are devices that can shut off the EV circuit when the clothes dryer is running. There are also devices that can monitor the main breaker and shed loads like the EV charging when the total load approaches the main's rating.
 
Or will codes always require a theoretical load calculation vs demonstrated load?
I have heard that you can definitely do either one, but I think the requirement for demonstrated load has to have 1 past year of data, which is sometimes a problem if someone has just recently moved into the house. Getting the measurement is another issue, but if you contact the electric company and ask them for that, they can probably pull that data from your service and mail you a report of it.
 
You can also use special devices to ensure that your new load (EV charging) is not coincident with other loads. For example, there are devices that can shut off the EV circuit when the clothes dryer is running. There are also devices that can monitor the main breaker and shed loads like the EV charging when the total load approaches the main's rating.
Can you link me to one of these devices? Thanks
 
Can you link me to one of these devices? Thanks
Two examples for slightly different uses:

DCC-9/10/12 -- Controls whether the EVSE is energized based on total load on the electrical service or on specific branch circuits.

Dryer Buddy of various types turns one outlet into two and provides for switching (manual or automatic) which one of the two of them is energized.
 
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