1- 12 kw electric range
20 kw of electric space heating (1 central elect. heating unit)
1- 5 kw electric water heater
1-central air conditioner, 9 kw
1- dishwasher, 1 kw
1- disposal, 0.9 kw
1- electric clothes dryer, 4500 watt

1- 14 kw electric range
25 kw of electric space heating (electric baseboard heat)
1- 5 kw electric water heater
1-central air conditioner, 9 kw
1- dishwasher, 1 kw
1- disposal, 0.9 kw
1- electric clothes dryer, 4500 watt
1- compactor 1 kw
1- well pump 3/4 hp, 240 volt (560 va)

1- 12 kw electric range
1- electric clothes dryer, 5500 watt
all space heating and water heating are gas

2 each 4kw wall mounted ovens and one 5.1 kw counter-mounted cooking unit
1- 4.5 kw water heater
1- 1.2 kw dishwasher
1- 5 kw clothes dryer
6- 7 amp, 240 volt room air conditioners (remember to convert to va)
1- 1.5 kw permanently installed space heater

2. What is the demand load for 1 range rated 9 kw?

3. What is the demand load for 3 ranges each rated 11 kw?

4. What is the demand load for 15 ranges each rated 9 kw?

answers:

1. 8 kw

2. 8 kw

3. 14 kw

4. 30 kw

Table 220-19, Note 1: For ranges individually rated more than 12 kw but not more than 276 kw, the maximum demand in Column C shall be increased by 5 percent for each kw of rating or major fraction thereof by which the rating of each individual range exceeds 12 kw:

Using column C and note 1:

5. What is the demand for 1 range rated at 16 kw?

6. What is the demand for 6 ranges rated at 18 kw each?

7. What is the demand for 5 ranges rated at 18 kw each?

8. What is the demand for 20 ranges rated at 14 kw each?

Answers:

5. 16 - 12= 4. 4 x 5 percent= 20 percent. Increase the column C value for 1 range by 20 percent. 8 x 1.20 =9.6 kw

6. 18 - 12 = 6 x 5 percent = 30 percent. Increase the column C value for 6 ranges by 30 percent. 21 x 1.30 = 27.3 kw

7. 18 - 12 = 6 x 5 percent = 30 percent. Increase the column C value for 5 ranges by 30 percent. 20 x 1.30 = 26 kw

8. 20 - 12 = 8 x 5 percent = 40 percent. Increase the column C value for 20 ranges by 40 percent. 35 x 1.4= 49 kw

Using column A and note 2:

9. What is the demand load for the service or feeder supplying the following ranges?

1 range rated at 20 kw

4 ranges rated at 15 kw each

2 ranges rated at 9 kw each

10. What is the demand for the service or feeder supplying the following ranges?

2 ranges rated at 20 kw each

3 range rated at 10 kw each

2 range rated at 14 kw each

Answers:

9

20 + 60 + 24 = 104 divide by 7 = 14.85 - 12= 3 x 5percent =15 percent above the column C value for 7 ranges. 22 x 1.15=25.3 kw

10

40 + 36 + 28 = 104 divide by 7 = 14.85 - 12 = 3 x 5 percent = 15 percent above the column C value for 7 ranges. 22 x 1.15 = 25.3 kw

11. What is the demand load for two 3 kw cooking appliances in a dwelling unit?

from column A, 6000 x 75 percent = 4.5kw

12. What is the demand load for one 6 kw cooking appliance in a dwelling unit?

from column B, 6000 x 80 percent = 4.8kw

13. What is the demand load for two 3 kw ovens and one 6 kw cook top in a dwelling unit?

from column A, 6000 x 75 percent = 4.5kw, from column c, 6000 x 80 percent = 4.8 kw, add 4.5 kw to 4.8 kw for a total demand of 9.3 kw

10 hp = number 10 THHN
15 hp = number 6 THHN
20 hp = number 4 THHN

2. 67.5 + 28 + 42 = 137.5 from Table 310-16, use 1/0 THHN

34 x 1.75 = 59.5, round up to 60 amps per 430-52c(1) exception 1

3. 34 x 1.25 = 42.5, number 8 THHN per table 310-16

4. 34 x 2.5 = 85, round up to 90 amp

5. Conductors

Motor 1, 22 AMP table 430-150, x 1.25 430-22, =27.5, table 310-16, number 10 THHN wire
Motor 2, 28 amps table 430-150, x 1.25 430-22, =35, table 310-16, number 10 THHN
feeder, 35 + 22 = 57, table 310-16, number 6 THHN
short circuit, ground fault protection

Ground Fault and Short Circuit Protection:

22 x 2.5 = 55 round up to 60 amp per 430-52c(1) exception 1 and 240-6
28 x 2.5 = 70 feeder: 70 + 22= 92, round down to 90 amps per 430-62

6. Time Delay fuses:

22 x 1.75 = 38.5, = 40 amps, round up to next standard size per 430-52c(1) exception 1
28 x 1.75 = 49, =50 amps