Calculating service for a shell bldg's

[stuartdmc]

While recalculating the electrical loads for a new service on a large commercial property shell only, TI to follow. I noticed that the EEOR sized the entire spaces using the square foot method, for example; future retail space 26,800s.r. x 20w/sq f.t.=52,800w and restaurant loads at 30w/sq ft. = 201,150, etc.

After totaling all of spaces he came up with 4,000,657w @ 4,818 amps thus suggesting that a 5000amp serves would be acquitted.

My question is,
After the total connected loads have been determined using the square foot method, shouldn't you multiply the total by 1.25% therefor the service size should be 6000amp?

If it is necessary to apply the 1.25% to the total Con. load, where in the NEC would it be referenced?

 

[Smart $]

There is no correlation between Code mandated demand load calculation and estimating future load as done by the EEOR.

FWIW, factoring by 125% is only Code required for the continuous load portion of the service. I imagine that is figured into the estimated demand W/ft².

 

[stuartdmc]

While recalculating the electrical loads for a new service on a large commercial property shell only, TI to follow. I noticed that the EEOR sized the entire spaces using the square foot method, for example; future retail space 26,800s.r. x 20w/sq f.t.=52,800w and restaurant loads at 30w/sq ft. = 201,150, etc.

After totaling all of spaces he came up with 4,000,657w @ 4,818 amps thus suggesting that a 5000amp serves would be adequate.

My question is,
After the total connected loads have been determined using the square foot method, shouldn't you multiply the total by 1.25% therefor the service size should be 6000amp?

If it is necessary to apply the 1.25% to the total Con. load, where in the NEC would it be referenced?

correction "adequate".

Similar to the scenario above, when sizing a service upgrade, it's typical to add 125% to the a service demand once determent the load whether from a 30 day recorded tape of the loads or an average 12month utility peak demand load. I thought or it made since to me that 125% would also apply to this as well, safer to over size it than under.

Thanks for your comment(s)

 

[Smart $]

correction "adequate".

Similar to the scenario above, when sizing a service upgrade, it's typical to add 125% to the a service demand once determent the load whether from a 30 day recorded tape of the loads or an average 12month utility peak demand load. I thought or it made since to me that 125% would also apply to this as well, safer to over size it than under.

Thanks for your comment(s)

No average. Simply, the peak demand. Code uses the terminology "maximum demand".

Yes, you are required to factor the peak demand by 125% under the optional method of 220.87 for existing loads. There is no way of determining by peak data how long the peak lasted or how steep of a peak it was. In other words, no way to verify how much of the load is continuous at any one point in time... so Code takes the conservative approach and assumes all the peak demand load is continuous.