Surge versus Load Shedding Protection: Clarifying common misunderstandings

Introduction: Load Shedding Surge Protection

Written by Jason Roper of Africa Surge, a Safehouse member.

In the current climate, the impact of load-shedding on our electronic and electrical devices, both at home and in the office, is substantial, affecting not just personal convenience but also the broader economy.

This article doesn’t delve into the economic repercussions or the debate over energy sources; instead, it focuses on dispelling prevalent misconceptions around load-shedding, particularly those concerning surge protection. These misunderstandings, if not addressed, could prove costly for consumers, business owners, and insurance professionals alike.

To lay a solid foundation, let’s begin by defining key terms related to this topic. It’s common to encounter the term “surge” in various media outlets, often used broadly to describe electrical phenomena during load-shedding. However, this usage can be misleading. In our context, “load-shedding” specifically refers to the deliberate power cuts implemented by utility providers. While the term is uniquely pertinent to our country, the concept of power outages is universally understood. Both scenarios typically involve fluctuations in voltage levels, characterised by increases (swells) and decreases (sags).

Understanding Surge, Sag and Swell

  • Let’s clarify three crucial terms – Surge, Sag and Swell – and add two more for context: Normal and Interruption.
  • Normal” denotes the standard, expected electrical waveform provided by power utilities – in South Africa, typically 240/220Vac, as per Eskom (1).
  • Interruption,” on the other hand, signifies a complete lack of power, or 0Vac.
  • A “Sag” (2) or voltage dip, is a short-duration decrease in voltage, ranging from milliseconds to several seconds. Instances of sags dropping to 175Vac have been reported, with significant impacts on electrical systems, damaging components in appliances like refrigerators and high-end office equipment.
  • Swell” refers to a short-term increase in voltage, observed between 285 to 380Vac, which can cause severe damage to electronic devices.

Both sags and swells are commonly associated with load-shedding and power outages.

AC Waveforms Surge Sag Swell

  • “Surge”: According to the International Electrotechnical Commission (IEC), (3), a surge is a current and footage waveform, ranging from 6000 to 20kVac, characterised by its rapidity, occurring in microseconds. 

Understanding Surge

Surge versus Load Shedding Protection


Lightning Surge


The speed of a surge is critical to understanding its impact during load-shedding events. Surges are quick, causing electronic components to pop or break apart. In contrast, swells and prolonged over-voltages allow components to overheat, potentially leading to fires.

This distinction is crucial when considering surge protectors. These devices are designed to respond at speeds far exceeding the duration of a typical surge, cutting off the surge voltage during its rise time (8 microseconds). Standard surge protectors are effective against high voltage and high speed surges but are less effective against sags and swells.

Understanding Surge Protectors

Not all surge protectors are created equal. While most are designed to counteract high-speed, high-voltage surges, they often do not respond adequately to swells. Advanced models with additional circuitry can offer some protection against swells, but these tend to be more expensive and are not standard in surge protector design. Innovations in this field have led to the development of specialised load-shedding protectors, addressing the unique challenges posed by both surges and swells resulting from load-shedding.

Surge and Load Shedding Protector

Understanding these electrical phenomena is crucial, not just locally but globally. It’s important to recognize that a surge protector is not synonymous with a load-shedding protector. While some surge protectors can handle longer durations and lower voltages, they are not ideal for load-shedding scenarios. Products specifically designed to address swells and sags are different in design and function from surge protectors. High-quality load-shedding protectors are generally more expensive, given the complexity and quantity of their components. They often include an integrated circuit (IC) that continuously monitors voltage from the utility provider.

Our Promise - Your Electrical Safety Compliance

Safehouse’s core promise is that a Safehouse product is a safe product. The Safehouse mark stands for absolute adherence to the highest electrical safety standards.  The Electrical Safety Compliance Safehouse.

Download the Safehouse Guide to Surge Protection here.

Find a list of safe products here.


In conclusion, while some manufacturers (4) offer combined surge and load-shedding protection devices, it’s vital to understand that these are fundamentally different in their operation and purpose. The intricacies and technological advances in this field continue to evolve, offering more robust solutions to the challenges posed by electrical fluctuations. Stay tuned for further insights in future articles.

Safehouse invites you to explore our initiatives, or follow us on LinkedIn and consider becoming part of a community that protects lives and livelihoods. Together, we can build a future where electrical safety is not just an expectation but a guarantee.

Join us in this vital mission and become a representation of safety and excellence in the electrical industry.