How do generators work?


A generator supplies electrical power during a power outage and crucial to have as back-up since security systems can falter without electricity. They are available in different electrical configurations and used for various purposes, both commercial & domestic.

With power outages being a common occurrence in South Africa, having a generator as back up for electricity usage, is a good idea. Though there are a few types of generators (large fixed position generators, industrial, domestic, mounted, diesel and portable), the most common backup generator for domestic use will be the portable or fixed. These generators work with different fuel ranges, from petrol, bio-diesel, diesel and LP Gas. All of these have different pros and cons.DY5000L_generators_bbf

Naturally, the small the generator, the smaller the fuel tank and the more you would have to refuel – should you run them often. These generators can be directly connected to your property by using a transfer switch and may be started manually or automatically. If you have an automatic system, the generator will automatically switch itself of when the power is restored.

How do I choose a fuel option?

This choice should include the availability of the specific fuel in your area. Gas generators are not too common. A diesel generator is commonly used, unfortunately, these generators are also the most costly. Petrol generators are the most used, with the only disadvantage of the petrol being highly combustible and cannot be stored for too long. These types of generators come in various sizes and generating different power outputs.

The smaller petrol and diesel generators are great for home use. These type of generators does cost more to run, as they use fuel and not renewable energy sources like solar or wind generators, but they are still a cost effective way to generate power during power outages.

Where do I install my backup generator on my property?

Any generator should not be positioned close to windows or doors as carbon monoxide is deadly and should best be mounted on a cement floor outside. Remember, these machines create a fair amount of noise and air pollutions. Always make use of a certified electrician if you are installing a transfer switch (this is required by law).

What is a transfer switch?

When the power goes out, there is a delay of about 15-20 seconds before the generator automatically kicks in. You will need a UPS is you can’t afford to lose power to your computers. The generator will continue to run until the power is restored. When that happens, the generator switches off automatically too.

What is a UPS?

A UPS, otherwise known as an uninterruptible power supply, is basically an extra battery to ensure your computer keeps running when you experience a power outage, ensuring no power interruption to these devices.

How do portable generators work?

A portable generator is a machine that converts mechanical energy into electrical energy from an external source. These generators work with petrol/diesel and are great for emergency power systems. These compact generators, can power multiple appliances for up to 8 hours. Usually used with extension cords. Do take in mind that you will need to make use of lamps, as lights can’t be used with generators. With portable generators, you will need an extension cord, just ensure you are using the correct sized cord to carry the electric load.


Generators (petrol & diesel) cost about R3500 moving upwards.

Backup generators produce more power than portable generators (between 5kW up to 100’s of kW).

Take note: A generator can never be used indoors as the exhaust gasses from the generator are highly toxic and can be fatal.

Use the grid below to see which size portable generator you will require:

Rated Watts



5 – 6.5 kW

Good for basic appliances and a few extras.

A few lights & refrigerators.

8 – 10 kW

An emergency system providing enough comfort & security.

Survival appliances, a whole kitchen and 2-3 rooms.

15kW-25 kW

A powerful system with power to run a small home easily.

Same as above, add laundry room and heaters/coolers.

30kW +

A powerful system to run a large property.

Complete comfort.


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