Milkman Telling you to Buy a Cow? Eskom Issues Recommendations on what Generator to Buy!

Eskom has published a document titled “Selecting the right type of generator”, providing guidelines on which generators to buy, and how to connect them to your home. Does not really instill much confidence for their future plans in them does it?

Residential generators are available in a variety of sizes, with power supply capacities ranging between 5kW and 50kW. These generators are petrol or diesel driven.

Eskom warned that generator under-sizing is one of the most common mistakes committed by buyers.

“Not only could it damage your generator, but it can also damage other assets connected to it, creating hazardous situations,” said Eskom.

Eskom said generator users must remember that more power generation capacity is always better than less.

Things to consider when buying a generator

Eskom said home owners must consider the following when buying a generator:

  • Safety: Generators need to be correctly installed and connected to the building via a suitable and approved change-over switch, including installation of an over current protection circuit breaker in the main distribution board by a certified electrician.
  • Total electrical load to be connected.
  • Voltage, frequency, and phase.
  • Does the generator need to start automatically? If so, then an automatic mains failure mechanism needs to be installed.
  • Suitable location for the generator – outside or in vented area (not to be installed in an enclosed area or indoors).
  • Acceptable noise levels.
  • Altitude and running time.

What should you power with the generator?

  • Kitchen, bathroom, and sitting room lights
  • One plug in kitchen for kettle or cellphone charger
  • Refrigerator/freezer
  • Television and decoder
  • Garage door opener
  • Microwave/oven
  • Computer
  • Security – alarm systems/electric fencing/lighting

How big a generator should you get?

The capacity of the generator depends on the total of the electrical loads you want to power simultaneously, measured in Watts.

This capacity depends on the sum (maximum total load expected at any given time) of the electrical loads you want to power simultaneously, measured in watts. First, add up all the loads you know you want to be able to run simultaneously. Then, as a precaution, figure out which electrical item in your house requires the most electricity to start its motor and add that to your total, bearing in mind that the startup current of a pool pump motor, for example, is about 1.4 times the running load and large items like air conditioners and some refrigerators can be two or three times what they use while running. Make sure your generator can accommodate that extra electricity needed so that larger items won’t overload the system if they start up. Every generator has two wattage ratings: running wattage and surge wattage. Generators are rated for surge wattage because they should have some excess capacity in case the load you need is temporarily larger than what you’ve calculated. When you buy a generator, choose the size based on the running wattage and its surge wattage should automatically fall into line with what you need. If you’re worried about needing more surge wattage, buy a larger generator.

All heating appliances – such as stoves, heaters, dishwashers, geysers, kettles, tumble dryers, toasters and hairdryers – draw the most power, and should be switched off.

PCs and electronic equipment don’t use much power, but are voltage sensitive. If the generator does not deliver a constant voltage and there are dips and spikes, equipment may suffer damage.

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Typical generator sizes needed:

The table below provides an overview of the typical generator sizes needed for households.

Generator sizes needed
Small portable generator (3kW to 4kW) Mid-sized portable and small stationary generator (5.5kW to 8kW)
What it can power: What it can power:
  • Refrigerator (600 watts)
  • Microwave (1500 watts)
  • Sump pump (600 watts)
  • Several lights (400 watts)
  • TV (200 watts)
  • Refrigerator (600 watts)
  • Microwave (1500 watts)
  • Sump pump (600 watts)
  • Several lights (400 watts)
  • TV (200 watts)
  • Portable heater (1300 watts)
  • Computer (250 watts)
  • Heating system (500 watts)
  • Second pump (600 watts)
  • More lights (400 watts)
Large portable generator (10kW) Large stationary generators (10kW to 15kW)
What it can power: What it can power:
  • Refrigerator (600 watts)
  • Microwave (1500 watts)
  • Sump pump (600 watts)
  • Several lights (400 watts)
  • TV (200 watts)
  • Portable heater (1300 watts)
  • Computer (250 watts)
  • Heating system (500 watts)
  • Second pump (600 watts)
  • More lights (400 watts)

Add a choice of:

  • Small water heater (150 litre – 200 litre hot water geyser – 3000 watts)
  • Central air conditioner (5000 watts)
  • Electric range (5000 watts)
  • Refrigerator (600 watts)
  • Microwave (1500 watts)
  • Sump pump (600 watts)
  • Several lights (400 watts)
  • TV (200 watts)
  • Portable heater (1300 watts)
  • Computer (250 watts)
  • Heating system (500 watts)
  • Second pump (600 watts)
  • More lights (400 watts)

Add a choice of:

  • Small water heater (150 litre – 200 litre hot water geyser – 3000 watts)
  • Central air conditioner (5000 watts)
  • Electric range (5000 watts)
  • Clothes washer (1200 watts)
  • Electric dryer (5000 watts)

 

What’s the difference between a standby generator and a backup generator?

A standby generator is permanently installed apparatus, much like a compressor for a central air-conditioning system. Its engine runs on natural gas or propane. A backup generator is a small, petrol-engine generator that you wheel into position outside the house and then plug into the transfer switch. Or it can be connected to electrical loads via heavy-duty extension cords.

If it’s raining outside, can you put the generator in the garage and run it there, as long as the door stays open?

No. Never run a generator inside a house, inside a garage, under a carport, on a porch, inside a screened porch or near an open window. Even with the garage door open, the carbon monoxide (CO) in the generator’s exhaust can sicken somebody inside the house or, in the worst case, even kill someone.

Generators are loud. What can be done about that?

Unfortunately, not much. More mechanically advanced generators do a better job than older ones at adjusting engine rpm to their electrical output. This reduces their running speed, which is quieter and conserves fuel. The simplest way to reduce generator noise is to reduce the electrical load you’re imposing on it.

Does the generator need to be grounded?

Follow the instructions in the owner’s manual. If the manual calls for grounding the generator, that’s relatively easy to do. One simple way is to run a 12-gauge ground wire from the grounding terminal on the generator to a copper ground rod you’ve driven into the soil next to the generator. (The generator will have a grounding terminal symbol to help you identify the terminal’s location.)

As an alternative, the manual may ask you to run a ground wire from the generator’s grounding terminal to the ground bus inside the house’s service panel. As long as you follow the instructions provided in the manual, the generator will be safely grounded.

Caution: When a power failure occurs please keep candles and matches from the generator fuel tanks.

 

Eskom-peak-demand-graph

 

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