By Dr Andrew Dickson, engineering executive at CBi-electric: low voltage

Meeting insurer requirements doesn’t necessarily guarantee that South Africans are sufficiently protected against power surges. In a country where lightning strikes, load shedding, and grid instability are everyday occurrences, this oversight could have costly consequences for both parties.

Insurers are increasingly requiring surge protection devices (SPDs) for property owners. However, do these requirements genuinely safeguard policyholders and their assets, or are they simply fulfilling a compliance obligation without offering meaningful protection against real-world electrical threats?

Not All Surges Are the Same

Electrical surges vary in origin and intensity. Some are dramatic, like those caused by direct lightning strikes. Others are smaller but equally damaging, such as switching transients triggered when power is lost and restored during load shedding, or by everyday fluctuations caused by short circuits and other electrical faults.

These surges behave differently and pose unique risks. Yet many insurance policies recommend a one-size-fits-all approach to protection - typically requiring the same type of SPD regardless of a property’s location, use case, or exposure level. This blanket approach may fall short of protecting the very assets these policies are designed to cover.

What Insurers Require vs What Properties Need

While insurers have some alignment with the national wiring code by mandating Class 2 SPDs for low-voltage installations, their insistence on higher kA ratings reflects a misconception that higher peak values are a silver bullet in providing effective protection, which is not necessarily the case.

For reference, there are three classes of SPDs, namely 1, 2 and 3. Class 1 SPDs are designed to handle extreme surges from direct lightning strikes and are typically installed where power enters a premises or building. They act as the first line of defence, intercepting high-energy surges before they can enter the internal electrical distribution system. These devices are also typically used in remote areas, locations at high risk of direct lightning strikes on incoming services, or where there's a threat of explosions or damage to sensitive equipment.

More common in domestic settings, Class 2 devices offer protection from smaller surges associated with indirect lightning strikes or switching transients in urban areas.

Class 3 protectors provide localised protection for sensitive electronics like televisions, routers, or gaming systems and are located at the point of consumption.

Each class serves a different purpose, and the best protection often involves a layered approach. Tailoring the solution to the property’s risk profile is essential.

The Truth About 40kA Ratings

While the SPD class defines the type of surges the device is designed to handle, the kA rating is another piece of the protection puzzle. This rating indicates the maximum current the device can divert in a single event.

Insurers often specify a 40kA rating, based on the belief that higher ratings equate to better protection. But that’s not always true. It’s like using a 10-pound hammer to drive in a 10mm nail: it might work, but it’s excessive and inefficient.

In practice, what matters more is how the SPD performs under repeated smaller surges – the kind that happen most often and result in cumulative wear. Devices degrade over time, regardless of their kA rating. That’s why the joule rating, which indicates how much total energy the SPD can absorb, is an important guide to long-term protection. Both values - the kA rating and the joule rating - should be considered together when specifying SPD requirements for an installation. This ensures a more holistic approach to surge protection and means more effective, practical policy guidelines from insurers.

Moving Beyond Compliance to Genuine Protection

It’s encouraging that insurers are starting to mandate SPDs, but these recommendations must go further. Relying solely on class and kA rating without considering real-world electrical threats can leave gaps in protection or provide a false sense of security.

National standards for protecting people, structures, and devices are well established and clearly outline how protection should be correctly applied. However, a 'sledgehammer approach', where protection is applied in a broad or excessive manner, does not guarantee the intended level of safety. As a result, the actual protection may fall short of expectations. This leaves insurers vulnerable to claims, despite having enforced requirements, and questioning why the anticipated risk mitigation hasn’t materialised.

By engaging electrical engineers and applying the national standards, insurers can ensure that surge protection is not just a tick-box exercise – but a robust defence against electrical damage. The ultimate objective should be to protect people, property, and productivity with solutions grounded in both science and context, rather than merely fulfilling an underwriting requirement.