Dwelling Load Calculation

[david luchini]

But I guess your saying, I can take 75% off for the total calculation for all 20 Apartments.

Yes, you have 40 appliances on the same service that the 220.53 demand factor can be applied to (take 25% off)

 

[BatmanisWatching1987]

Yes, you have 40 appliances on the same service that the 220.53 demand factor can be applied to (take 25% off)

Thanks for the help, I will take the 75% for total incoming service. I'm not sure what you meant by 25%?

So for each apartment feeder, I will need a minimum of 120 AMPS.

 

[david luchini]

Thanks for the help, I will take the 75% for total incoming service. I'm not sure what you meant by 25%?

So for each apartment feeder, I will need a minimum of 120 AMPS.

I would look at the optional calculation in 220.82 for each dwelling unit, and in 220.84 for the total building.

 

[Dennis Alwon]

You don't take 75% off the service. You can add up all the appliance and multiply by 75% and use that number

 

[BatmanisWatching1987]

I would look at the optional calculation in 220.82 for each dwelling unit, and in 220.84 for the total building.

I used the Method 220.82, but I don't think I am getting the correct incoming service.

For Single Phase I got 911 AMP and for Three Phase I got 527 AMP.


I also attached my updated Standard Calculation for Single and Three Phase.

 

[david luchini]

I used the Method 220.82, but I don't think I am getting the correct incoming service.

For Single Phase I got 911 AMP and for Three Phase I got 527 AMP.


I also attached my updated Standard Calculation for Single and Three Phase.

View attachment 22610 View attachment 22611 View attachment 22612

Your total lighting and small appliance load is wrong on the optional method. That's why your total load is low.

 

[BatmanisWatching1987]

Your total lighting and small appliance load is wrong on the optional method. That's why your total load is low.

Thanks for noticing that. I updated the Optional Calculation and now I get
For Single Phase I got 1021 AMP and for Three Phase I got 590 AMP.

I notice I made the same mistake for Standard and Three Phase as well, so would I use the amount of 3,856 VA which used the demand Factor of 3000 VA @ 100% and 35% after.


So for each apartment feeder, I will need a minimum of 120 AMPS based on Standard Calculation and optional comes out to 134 AMPS

 

[david luchini]

Thanks for noticing that. I updated the Optional Calculation and now I get
For Single Phase I got 1021 AMP and for Three Phase I got 590 AMP.

I notice I made the same mistake for Standard and Three Phase as well, so would I use the amount of 3,856 VA which used the demand Factor of 3000 VA @ 100% and 35% after.


So for each apartment feeder, I will need a minimum of 120 AMPS based on Standard Calculation and optional comes out to 134 AMPS

View attachment 22615

I think the 220.82 optional calculation for each apartment feeder would come out around 102 Amps.

 

[BatmanisWatching1987]

I think the 220.82 optional calculation for each apartment feeder would come out around 102 Amps.

Could I ask how you come up with 102 AMP since I just updated my Optional Calculation for 1 Dwelling units using 220.82, but I got 83 AMPS.

 

[topgone]

Not sure how you got 35kW. Since 8kW * 28% * 20 will equal to 44,800.

See note 3 on Table 220.55.

 

[david luchini]

Could I ask how you come up with 102 AMP since I just updated my Optional Calculation for 1 Dwelling units using 220.82, but I got 83 AMPS.

View attachment 22616

The 220.82 demand factor does not apply to the air conditioning