Electrical capacity

Build Your Own Solar Water Heater

Build Your Own Solar Water Heater

Get Instant Access

The unit of electrical power is called a watt. Watts are equivalent to volts times amps (W = V x A). The electrical service that I have found in houses and the corresponding equivalent power capacity is shown in TABLE 12-1.

In older houses, unless the electrical service has been upgraded, you are likely to find 30 and 60 amps at 110 or 110/220 volts. Any service less than 60 amps at 110/220 volts is considered inadequate. Homeowners with such electrical service might indicate that they have lived in the house for twenty or thirty years and have found the service totally

Temporary Wiring Diagram Amp Service

Central air conditioner

Fig. 12-3. Generalized wiring diagram for a residential structure.

100- to 200-amp main service panel with master disconnect

Central air conditioner

Fig. 12-3. Generalized wiring diagram for a residential structure.

Table 12-1. Power capacity.

Amps

Volts

Watts

Evaluation

30

110

3,300

Inadequate

30

110/220

6,600

Inadequate

60

110

6,600

Inadequate

60

110/220

13,200

Marginal (small house only;

no major appliances)

100

110/220

22,000

Minimum

150

110/220

33,000

Good

200

110/220

44,000

Very good

Table 12-2. Power requirements of appliances.

Power requirement

Appliance

(watts)

Attic fan

400

Central air conditioning

6,000

Clothes dryer

4,500

Dishwasher

1,500

Forced-air furnace (electric heat)

28,000

Freezer

575

Garbage disposal

900

Hand iron

1,000

Instant hot water dispenser

1,000

Lamp (each bulb)

25-150

Microwave oven

500

Range, electric

8,000

Portable room heater

1,600

Room air conditioner

1,100

Sauna

8,000

Steam bath generator

7,500

Television (color)

150-450

Water heater

2,500 -4,500

acceptable. That might be true—for them— because they have adjusted to the lower electrical capacity by not using any major electrical appliances. Nevertheless, if you buy a house with low electrical service, you will probably have to upgrade the service after you move in.

The capacity of the electrical service should be great enough to satisfy the power requirements of the various electrical appliances to be used. Table 12-2 shows some typical electrical appliances and their associated power requirements.

Considering the many electrical appliances that are available to the homeowner, the minimum electrical service is 100 amps at 110/220 volts. However, if the house is small and the intention is not to use many electrical appliances, 60 amps at 110/220 volts will probably suffice. When a house is equipped with an electric water heater, electric range, electric clothes dryer, and a central air-conditioning system, it should have at least 150-amp service. If electric heat is used in addition to the above appliances, the house should have 200-amp service.

Was this article helpful?

0 0

Post a comment