Calculations for Dwelling Units Flashcards
Table 220.42 demand factors for dwelling units
First 3000va at 100%
From 3001 to 120000 at 35%
Remainder over 120000 at 25%
A demand factor of ___% can be applied to appliances that are fastened in place
75
The calculated load for a dryer must be ___va or nameplate, whichever is higher
5000
Service conductors supplying a single dwelling unit may have its ampacity sized to ___% of the service overcurrent device rating
83
The neutral load for household cooking equipment is considered ___% of the calculated load
70
The demand factors for general loads for the optional method are
The first 10kVA at 100%
The remainder at 40%
When using the optional method for a dwelling unit service calculation, the only connected load not subject to the demand factors are the ___
Heat/AC loads
The smallest allowable service size for a dwelling unit
100a
An example of linear lighting load
Incandescent
Sections
Taps for Branch Ckts
Taps for feeders
- 19
240. 21
Heat/AC for optional method
A/C ___
Heat ___
3 or less heat ___
4 or more heat ___
100%
65%
65%
40%
Lighting ckt capacity equations
Noncontinuous loads
Continuous loads
OCPD x Volts = Va capacity
OCPD x Volts x 80% = Va capacity
The minimum va for a mobile home lot
16000va
Table - demand factors for mobile homes
550.31
Areas where lighting are not considered continuous
Dwelling units
Motel rooms
For a service over 200a, these demand factors can be applied to the neutral
1st 200a at 100%
Remainder at 70%
Nonlinear loads at 100%
For a 3 phase service, when converting from va or wattage to amps, a factor of ___ must be applied to the voltage
1.732
For a multi-family dwelling with laundry on premises, the laundry circuit becomes the ___, and can be reduced by what demand factors
Houseload
None
For a multi-family optional method calculation, the table for demand factors is
220.84
For a multi-family optional method calculation, heat and a/c is calculated
100% of A/C
100% of Heat
When calculating a duplex service size, the smaller of ___ shall be permitted
The standard method of the two dwelling units
The optional method per 220.84 of 3 identical units
Per Art ___, the largest motor in HP shall have ___% added to the final demand load
220.50
25%
