Getting Technical
Continued from page 55
rated at around 9kW so that it could cope with the appliances
being switched on in sequence and then operate at a baseload
of around 70% without producing too much clattering noise. In
addition, if he wanted the generator connected permanently into
the existing 230V wiring system the installation would have to be
professionally done and recorded which would cost an additional
amount of somewhere between R10 and R15 000.
However, the alternative of a simple six-plug bar adaptor
with a suitably sized built-in trip switch installed on an inside wall
would require installation only of a few metres of exterior supply
cable and normal 230V interior connection plugs and cables to
the appliances and the TV so that they could be connected or
disconnected, and switched on and off as required. This was what
he decided on and when I saw the completed installation, I was
suitably impressed – and envious. There was no getting away
from the noise of the generator, even though it was located in
a rain-protected open garden shed several meters away, but
the disappearance of virtually all the irritations brought on by
load shedding almost completely overshadowed this small
inconvenience. I found myself slipping into convenient thinking
wondering what the resale value of a generator would be;
remembering the times when power had been off during most of
a night and all of the following day; luckily I had kept just enough
old newspapers to mop up all the condensate from the fridge
and freezer; now – where was that pack of candles I bought a few
weeks ago?
When power subsided for the second time, it remained off for
almost six hours. Less than halfway through this powerless period
my laptop battery failed. The following morning, I went to the
local computer shop, owned and staffed by very knowledgeable
and friendly people. After only about 15 minutes I left with not
only a new computer battery but also another battery similar to,
Refrigerator or freezer (Energy Star)
Microwave oven
650 watts
800 watts
1000 watts
Incandescent lights
Television
Tube type
Flat screen (20”)
Flat screen (46")
Coffee maker (4 cup)
Dishwasher (cool dry)
Electric fry pan
Electric stove (8-inch element)
Automatic washing machine
www.hvacronline.co.za
although a bit larger than the batteries which operate driveway
gates and garage doors. Packed into a neat compact box around
the battery were electrical and electronic components making
up an assembly which automatically provided charging for the
battery as well as a 450 watt, 230VAC output.
Enough for a couple of lights, TV, charging a cell phone and
even back-up for a computer if necessary. At a price of R4 780
inclusive of VAT this new ‘appliance’ has so far delivered exactly
what it was designed to do – lighten the burden of load shedding
even if only for three hours or so. No heating or cooking but
simple gas cylinders and burners are better and more convenient
for those functions.
This commentary has been simply a personal experience
in a single residential dwelling referring to only a few domestic
and other appliances and electrically powered items. Obviously,
industrial, commercial, agricultural and many other organised
activities consume far larger amounts of electrical energy, often
within much smaller areas. We are told that Eskom still needs a
year or more to develop and consolidate into a settled situation
in which switching off supplies to designated areas becomes
a genuinely seldom-used option. However, there seems to be
a general feeling of transition from negative to positive which
sounds encouraging and appropriate for the future electrical
situation of South Africa.
Shown below are examples of recommendations by Eskom on
electrical power requirements for various domestic installations
and appliances.
POWER CONSUMPTION CHART
This chart is an example as to how wattage varies between
various electrical devices. It is not meant to be a strict guide to
calculate actual requirements. For the most accurate calculations,
refer to the owner’s manual of each device, tool or appliance, or
consult a professional electrician: RACA
Approximate starting watts
1 200 Approximate running watts
132-192
1 000
1 300
1 500
as indicated on bulb (i.e. 60W) 1 000
1 300
1 500
as indicated on bulb (i.e. 60W)
300
120
190
600
540
1 500
1 200 300
120
190
600
216
1 500
2 100
1 200
RACA Journal I May 2020
57