1. The optional method of calculation for dwelling units is reserved for ___. a. multifamily dwelling units only b. dwelling units with over 3,000 sq. ft. of usable space c. dwelling units supplied by service conductors with an ampacity of 100 amperes or greater. d. dwelling units with a 208Y/120-volt, 3-phase, electrical system only According to Section 220.82(A), the optional method of calculation is permitted only if the dwelling unit serviceentrance conductors or feeder conductors have an ampacity of at least 100 amperes. This calculation method applies to a single dwelling unit, whether it is a separate building or located in a multifamily dwelling. It applies to dwellings served by a 120/240- volt, single phase system or a 208Y/120- volt, 3-phase system. Generally, the optional calculation method provides an easier and less complex calculation method than the standard (general) method for computing the total demand load for feeders and service-entrance conductors. 2. When calculating the service-entrance conductors of a farm where all the buildings, including the dwelling, are supplied from a common service, the second largest individual load in the group shall be calculated at _____. a. 60 percent b. 75 percent c. 80 percent d. 90 percent Due to the fact all the equipment on a farm will not be used simultaneously for an extended length of time, it is permitted to apply the demand factors shown in Table 220.103 when calculating the farm service-entrance conductors. This table shows the second largest individual load may be calculated at 75%. 3. The entire area of a service pit located in a commercial major repair garage that is not provided with mechanical ventilation is classified as a _____ location. a. Class I, Division 1 b. Class I, Division 2 c. Class II, Division 1 d. Class II, Division 2 Table 511.3(C) indicates where mechanical ventilation is not provided in the below floor level service pit of a major repair