Okay, let's break down what likely happened based on your experience and the symptoms you described. It's a classic case of low voltage exacerbated by what's known as voltage sag during the restoration of power after an outage.

What happened


Power Outage

The initial bad weather caused a complete power outage. This is straightforward.2.

Power Restoration and Voltage Sag

When power is restored after an outage, the system is stressed. Multiple circuits are trying to draw current simultaneously as appliances try to start up. This can cause a temporary drop in voltage, a phenomenon known as

voltage sag or voltage dip. This sag can last for a few seconds to minutes.3. Low Voltage Symptoms



Dimmed Lights

Incandescent and halogen lights are very sensitive to voltage. A drop in voltage causes a significant drop in light output.

Fluorescent Lights Failing

Fluorescent lights require a certain voltage to strike the arc and start. Low voltage prevents this.

Gas Boiler Issues

Modern gas boilers rely on electronics to control ignition, gas valves, and safety circuits. These electronics are sensitive to low voltage and will often shut down or fail to start. The "reset" may fail because the voltage is still too low.

Induction Hob (U1 Error)

The "U1" error code almost certainly indicates an undervoltage condition, as you suspected. Induction hobs use sophisticated electronics and are very sensitive to voltage fluctuations.

Microwave Issues

The microwave's motor might turn (as it's a relatively low-power function), but the high-voltage transformer that generates the energy for cooking likely needs a certain minimum input voltage to operate.

Working TV, WiFi, Kettle

These devices likely have wider voltage tolerances, or switch-mode power supplies that can regulate the voltage better to compensate for the sag. Also, some of the TV's and the kettle's components may have warmed a little while power was gone and so worked more easily, if the sag was minor.4.

Return to Normal

After 5 hours or so, the power cycled off and then on. This allowed the power grid to stabilize as electrical equipment switched off when it lost power and then slowly started up as power returned to normal, reducing the strain on the supply and the voltage was able to return to its nominal level.

Why the temporary power had such an effect

The key is the

combination of factors: Overall System Load

The load on the local electricity grid was high immediately after the outage. Every home and business in the area was drawing power all at once.

Inrush Current

Many appliances, especially those with motors (like refrigerators, air conditioners, and some components in the microwave and boiler), draw a surge of current (called "inrush current") when they first start up. This further stresses the grid and contributes to voltage sag.

Sensitivity of Modern Appliances

Many modern appliances rely on sensitive electronics, which need a stable voltage to operate correctly.

What was the reduced voltage exactly?

It's impossible to say exactly what the voltage was without a meter. However, based on the symptoms, it was likely significantly below the nominal voltage (e.g., below 200V if your nominal voltage is 230V).

SWEB and Reduced Voltage

Your retired electrician friend's point about SWEB (now likely part of a larger energy company) deliberately supplying reduced voltage is generally correct. They wouldn't intentionally reduce the voltage as a matter of policy. However: Voltage Drop in the Distribution System

Voltage drop is inherent in any electrical distribution system. As electricity travels through wires, there is some voltage loss due to the resistance of the wires. This drop is more pronounced when the current is high (i.e., high load).

Fault Conditions

During and after a fault, the voltage can fluctuate significantly. This is an inherent consequence of the fault and the system's attempt to restore power.

Key Takeaways

What you experienced was almost certainly a result of low voltage due to the grid being overloaded immediately after a power outage, causing a voltage sag. The sensitive electronics in modern appliances are more susceptible to voltage fluctuations than older appliances. The system eventually recovered as the load on the grid stabilized.* It's unlikely that any of your appliances suffered permanent damage, as you observed. They were simply unable to operate correctly under the low-voltage conditions.

In summary, you witnessed a common post-power-outage phenomenon: a temporary but significant voltage sag that affected the operation of some of your appliances but didn't cause lasting damage. The fact that everything returned to normal after the load stabilized is a good sign. Flag for review