Generators - how to calculate household power requirements

Cape Town South Africa has been experiencing the worst blackouts ever from December 2005. These blackouts occurred due to damage at Koeberg nuclear power plant generator 1. Escom announced that Generator 2 is due for maintenance in March 2006 which may lead to further blackouts unless generator 1 could be repaired in time.

These blackouts lead to severe dissatisfaction from normal residents and business owners as they were stuck without any power since the weekend of 18 February 2006. An influx took place to hardware and outdoors shops as citizens were buying any energy generating device (from gas stoves to high-tech generators) they could lay their hands on in order to cope with the power outages.

The most often asked question when it comes to generators and household use thereof, is how could a normal person calculate the power requirements for a standard household in South Africa in order to ensure that they purchase the correct generator?

Step 1:
Determine the consumption. In times of blackouts it might be good practice to use only the items that are essential - in our example we would use the following:
Kettle
Refrigerator
TV
Lights

Step 2:
Determine the total watts required in order to run the appliances: (Complete list here)
Kettle = 1000 w
Fridge = 250 w
TV = 150 w
Lights x 4 (100w)= 400 w
TOTAL : 1800 w (1.8 KVA generator)

Step 3:
When a generator starts up, it uses quite a bit of power until it runs. Users should take this into consideration, when calculating the Watts required.
In order to compensate for startup power, we multiply the Watts by 2: 1800 W X 2 = 3,6000 (3,6 KVA generator)

In our example a 3.5 KVA generator will therefore be sufficient to supply this household with power.

Justin Kitson is a manager at Goscor Engines and Forestry division. Please visit the complete appliance power requirement list in order to calculate your generator power requirements.