Highly inconvenient but unless one is a hospital, or business that draws large amounts of power for production of widgets and results in a loss of revenues, it is just really irritating at home.
What can one do for the home and what are the cheapest options?
In every case it is going to be an expense and generating one’s own power from either a generator or UPS will be to overcome the inconvenience.
Buy a Generator
- A 5,5 kVA generator will cost in the region of R9,000 from the likes of Makro or Builders Warehouse.
- This will be more than adequate for running all your lights and essential appliances like the fridge, deep freeze, TV, DSTV, computers etc, but not adequate for kettles, hairdryers, electric oven, electric geysers, or oil filled radiators.
- The easiest way to do it is to run an extension lead from the generator to the plug or plugs that are on the electrical circuit or circuits that feed these essential appliances.
- You must turn ‘off’ the relevant circuit breaker(s) at the distribution board, before connecting the lead from the generator into the plug.
- Turn ‘on’ the generator and you then have power. It is best to run the generator to a level of at least 30% of its potential output, otherwise it will overtime damage the generator and the engine will generate excessive carbon build up.
- When the mains comes ‘on’ again, turn ‘off’ the generator, then remove the extension lead from the plugs, and only then turn the circuit breaker back ‘on’ at the distribution board.
- If Eskom power is fed back into the generator, it will in all probability damage the generator beyond repair.
- Expected cost of running the generator is R4,00 to R5,00 per kWh used, or over double mains power costs.
Changeover Generator Switch
- The next stage up is to install a changeover generator switch. This overcomes the inconvenience of running extension leads from the generator to the plug circuits you want to use, and avoids having to turn ‘on and ‘off’ the circuit breakers at the distribution board.
- The changeover switch will generally be located by the distribution board. A qualified electrician must install the unit.
- The principles are exactly the same as with the extension leads but simplified. When Eskom goes ‘off’, turn the switch ‘on’ at the changeover switch, and start the generator. When mains power come back ‘on’ turn ‘off’ the generator and turn back the changeover switch to ‘off’.
- A light or bell or both can be fitted on the changeover switch.
- Expected cost including installation R4,000 to R4,500
Automatic Generator and Changeover Switch
- The next stage up is to automate the whole process. When power goes off the generator will be started automatically and the changeover will switch power from Eskom to the generator and back again.
- A more sophisticated generator and changeover switch will be required, and an anticipated cost including installation will be around R23,000.
Uninterrupted Power Supply (UPS)
- The alternative to the noisy but powerful generator route is to go for batteries or a UPS.
- Very small systems can be bought for a few thousand Rands, but need to be installed on a similar basis to the generator and extension leads.
- Adding in a changeover switch adds to the costs.
- Batteries are charged from the mains through an inverter from 220V into stored 12V DC power. When being discharged they convert the 12V DC back into 220V AC.
- Depending on the type of batteries, deep cycle lead acid or gel batteries will be considerably cheaper than Lithium Iron. The number of cycles of lead acid batteries will typically be a third of Lithium, and discharging them below 50% will kill the batteries within a couple of years.
- As a guideline, a good UPS system will cost from around R23,000 (similar to an auto generator and switchover system), but the amount of hours that will be provided during load shedding will depend on the draw of the power used.
- Do not expect to be able to provide more than 4-6 hours of non-mains power unless a very large battery pack is installed. Cost of power used from batteries will again be in the region of R4,00 to R5,00 per kWh taking into account the cost of batteries and future replacement.
- Advantage is noise, and immediate switching over within milliseconds.
Solar Electric Generation (Solar Photo Voltaic)
- Thinking about generating one’s own electricity at home is a huge subject in itself.
- Have a look at our beginner’s guide to solar electric generation.
- Be aware before you start, that a small system will cost around R70,000 to R90,000 and in our opinion a decent home system for a family of four will cost from R180,000 and up.
- We get a lot of enquiries from smaller homes for solar electric to power fridges. We suggest you go for the options above relating to load shedding, before considering solar PV.