Surge Protectors – do they work?

How to understand what a surge protector does

Nobody wants to spend money on a "proper solution" to power surges. But you need a surge protector anyway, with or without load shedding. It won't keep the lights on, and it won't even keep your electronics working during load shedding like a UPS (Uninterruptible Power Supply) would, but it can offer some level of protection. 

But if you buy the cheapest one you can find, you are asking for trouble. Not all surge protectors are of a high standard, and many manufacturers aren’t really transparent about how helpful their devices may be in the event of a lightning strike or power surge.

Technically, a power "surge" occurs when the normal mains voltage increases for three nanoseconds or more – and in some countries with stable power grids they’re fairly rare.

Aside from lightning strikes (which most of these devices claim to protect against), surges occur when Eskom switches off (and on) your power. Most of the times this happens, devices such as computers, decoders, routers, and televisions may still be connected to the mains.

Voltage fluctuation can easily damage components in electronic devices, and even if the surge doesn’t immediately destroy your electronics, repeat surges will damage anything over time.

A good quality surge protector will divert "extra" electricity away from your equipment, and can save your sensitive electronics. But not all surge protectors are created equal – in fact some offer protection only marginally better than nothing at all.

Establishing how good a particular surge protector is can be difficult, but generally speaking, the more you spend, the more protection you’ll get. This means that the el-cheapo surge protectors sold at most electronics and hardware stores in South Africa may not be offering as much protection as they promise.

There are four key things to look out for when buying a surge protector:

1. Joules

A Joule is a measure of energy released over a period of time. For example, an average lightning strike releases about one billion Joules of energy over a fraction of a second. A surge protector Joule rating indicates how much energy it can absorb before it fails. The higher the number of Joules, the greater the surge protection provided. Go for the highest Joule rating (1000 minimum, but 2000 and above is better) you can afford for any computer equipment. If the voltage rises above an acceptable level, the surge protector suppresses the excess voltage to prevent it from causing harm. Specifically, internal components called metal oxide varistors (MOVs) absorb the excess voltage and divert it safely to the ground wire, preventing it from reaching the connected equipment.

2. Clamping Voltage

Clamping Voltage refers to the Voltage level at which the surge protector begins to attenuate or reduce the surge — the lower the better. The best surge protectors feature a clamping voltage of 300 Volts or less.

3. Response time

This determines the length of time your equipment is exposed to the surge before protection kicks in. Look for a surge protector that responds in less than one nanosecond.

4. UL Rating

Look for both the UL mark (a symbol consisting of a circle inscribed with “UL”) and a specific rating of “UL Listed,” or, even better, “UL 1449 Listed” or “UL 1449 Revision 2.” These marks indicate that the surge protector has undergone rigorous safety and performance testing by the Underwriters Laboratory and meets the minimum performance rating for surge protectors. Surge protectors without this mark or with only the label “UL” or “UL tested” offer insufficient surge protection capabilities – although this has no official recognition in South Africa.

Unfortunately, many plug manufacturers and retailers in South Africa neglect to mention all of these figures, or they bury them in complex acronyms and numbers that most average shoppers aren’t able to understand. Instead, they tend to shift the focus onto terms like "heavy duty rating", and focus on 'features' like "overload protection" and "comes in different colours". 

Next article : Choosing the best solution for Eskom's inadequacy – To UPS or not to UPS?