To unplug or not to unplug? That’s just one of many questions that plague South Africans living in the era of rolling blackouts. 

When the electricity supply suddenly returns after rolling blackouts, it can result in a power surge, which can potentially damage appliances. A power surge is a sudden and brief increase in the voltage of electricity, causing an increase in the current flowing to your appliances. The increase, as brief as three nanoseconds (billionth of a second), results in an electrical spike, also known as a power surge. During normal uninterrupted electricity supply, this can happen for a variety of reasons, such as lightning strikes, power company equipment failures, or the operation of power-hungry electrical devices such as air conditioners, refrigerators or elevators. 

As per Eskom’s own fact sheet on surge protection, “[Power surges], after repeated load shedding, outages/interruptions or heavy industrial load fluctuations may eventually cause damages. While these surges are nowhere near the intensity of lightning surges, they can be severe enough to damage components, immediately or gradually, through regular occurrences.”

While unplugging one’s appliances may seem like the most straightforward solution, it is not exactly the most practical, especially during periods of rolling blackouts of up to three times a day, which are often exacerbated by further unplanned outages in many parts of the country. The next best solution for many, is to invest in power surge protectors, which work by diverting the extra electricity away from one’s appliances.

A graphic representation of a voltage surge. Image credit: Eskom

The right surge protector for you

As explained on Eskom’s fact sheet and on reputable platforms such as HowStuffWorks, the vast majority of surge protectors work by conducting the extra current to the ground before it reaches your appliances. 

Others work by suppressing surges, slowing electricity down on its way through the live line. Others still have a built-in fuse that, should the mechanism fail to divert the surge, will overheat and cut off supply. This only works once, as the fuse will be destroyed when it overheats. Even more ideal for sensitive equipment such as computers, some surge protectors feature a “line-conditioning” system, which filters out smaller current fluctuations, referred to as “line noise”.

Which surge protector to choose?

However, besides the various features and the inner technical workings of different surge protectors, the main options to choose from range from whole-house surge protectors — which would be installed directly on the distribution board (DB) by an electrician — through to plug-in protectors, which can either be a single outlet plug adaptor or a power strip with multiple outlets. Some UPS battery backup systems also come with surge protection included. Then there are power surge stations which offer superior protection and line-conditioning for devices such as computers. Since telephone lines and data cables can also conduct high voltage, these power stations will often also feature inputs for phone lines, to protect routers, modems, and computers. 

A 12-way multi-plug adaptor with surge protection. Image: Ellies

Single outlet plug-in adaptors and multiple outlet power strips with surge protection are often the most affordable, costing a couple to a few hundred rands. However, one would have to buy a number of these for various wall outlets. It is also important to take into consideration that they might not work for all equipment. For example, they might not work effectively for devices that draw a lot of power such as refrigerators. 

Hence it is recommended to consider installing both a whole-house surge protector, as well as plug-in protectors to protect equipment from other surges within the house. For example, if a refrigerator and a computer are plugged into the same circuit, that could cause fluctuations within the home even with whole-house surge protection, hence an additional surge protector for the computer would protect your equipment and possibly extend its life. 

Computers in particular have voltage-sensitive components that can be easily damaged by power surges, instantaneously or gradually over time, and therefore it is recommended that even in the absence of rolling blackouts, one should always use a surge protector with a computer in order to extend its life.

Warranties, joules, and rands: Keep an eye on the numbers

As per Eskom, “determining how good a particular surge protector is, can be difficult, and will take comparative research into each system to identify its effectiveness. As a general rule of thumb, the more expensive the surge protector, the higher the level of protection. However, the cheaper surge protectors commonly provide sufficient protection for single loads. It is important to select protection suitable to the risk level and value of equipment to be protected.”

Read in Daily Maverick: Pay less for electricity by getting your head around Eskom’s sometimes confusing block tariffs

In addition to cost considerations, a few other numbers are important to consider. First, the clamping voltage. This indicates what voltage will cause the surge protector to divert electricity to the ground. The lower the number the better. Eskom advises looking for a clamping voltage no higher than 400 volts. Second is the energy absorption rating, which is indicated in joules. This tells you how much energy the surge protector can absorb before it fails. In this case, the higher the better, and Eskom advises consumers to “look for a protector that is at least rated at 200 to 400 joules. For better protection, look for a rating of 600 joules or more.”

Third is the response time. They don’t necessarily kick in immediately in response to a power surge, hence it is recommended to look for a surge protector that responds in less than one nanosecond. Additionally, some surge protectors come with a repair or replacement warranty for your appliances, should they be damaged while using the surge protector. For example, Ellies famously offers between R20,000 and R30,000 appliance repair or replacement warranties on various surge protectors, should equipment be damaged while using their products.

Last, it is also recommended to look for surge protectors with indicator lights, which will tell you if your surge protector is functioning properly. Some surge protectors will continue to conduct current, even if not functioning properly.

Single outlet plug-in adaptors with surge protection are often the most affordable, costing a couple hundred rands. Image: Ellies

What about lightning?

A number of manufacturers will clearly state that their surge protectors are not effective against lightning. However, some do not. Lightning produces far greater voltage fluctuations and will likely require a multi-component surge protection system to work effectively — one installed by experts. Hence, buying off-the-shelf items for lightning surge protection is not recommended. As per Eskom, “it is highly unlikely that surge protection will protect equipment against lightning and will certainly not do so for repeated lightning strikes… The best protection, with lightning, is to unplug your equipment.” DM/ML