how did they get this

[cjbouchard@bergco.com]

11kw x 1.15 range. 12650 i was reviewing some old threads on calculations and am trying to figure out where 1.15 came from .
My thought would be 1 range column C = although i see 3 more ranges at the bottom , Im still learning how to use 220.55 most of my carrer Iv been in Controls .


from former thread

1452sqft duplex 230V/115V
9.6KW electric heat
5HP A/C 230V
1200VA dishwasher 115V
1/2HP disposal 115V
4.5KW water heater 230V
4.0 dryer
15KW range

General method
1452 x 3va x 2units. 8712
1500x 3va x 2units. 9000
Demand. 8149
1200DW x 2 x 75% 1800
1127 disp. X 2 x 75% 1691
4500wh x 2 x 75% 6750
5000 dryer x 2. 10,000
11kw x 1.15 range. 12650
9600 heat x 2. 19200
Largest M. 1127x25% 282
73172/230V = 318A
Optional.
1452sqft x 3va x 3units. 13068
1500 x 3 x 3units. 13500
9600 heat x 3. 28800
1200 DW x 3. 3600
1127 disp. X 3. 3381
4500 W.H x 3. 13500
4000 dryer x 3. 12,000
15000 range x 3. 45000
132849 X 45% = 59782VA ÷ 230V = 260A8kw I will post the calculation i found and was trying to see if it was right .

 

[tortuga]

11kw x 1.15 range. 12650 i was reviewing some old threads on calculations and am trying to figure out where 1.15 came from .
My thought would be 1 range column C = although i see 3 more ranges at the bottom , Im still learning how to use 220.55 most of my carrer Iv been in Controls .


from former thread

<snip>
15KW range

11kw x 1.15 range. 12650

Looks like they are doing 2 units in those calcs.
How I calculate the load for two 15Kw range's is
Table 220.55 Colum C Maximum demand.
2 appliance = 11kW

Now my range is over 12 kw
the top of the table says see notes

Note 1 says to increase the 11kW 5% for each additional kW over 12
15 is 3kW over 12
kw over 12 X 5% = % to increase the value in column C
so 3 X 5% = 15%
Therefore
11kw x 1.15 range = 12650 kW

Also note
See 220.5 115/230 is not a standard voltage to use for calculations.
I always use 120/240 the use of 115/230 is not advised with Article 220 calculations unless its 'specified'.