# Does Loadshedding Damage Your Fibre Line?

Source: https://urbanx.co.za/knowledge-hub/fno-troubleshooting/loadshedding-damage-fibre-line

**Answer:** No. Loadshedding does not physically damage fibre cables because fibre carries light, not electrical current. However, power instability can reboot your ONT, delay PON registration, or damage power adapters if there is a surge. Persistent red LOS after loadshedding indicates a signal fault, not power loss.

Part of [FNO Troubleshooting & Fibre Diagnostics](https://urbanx.co.za/knowledge-hub/fno-troubleshooting) · 6 min read · by UrbanX Network Operations

## What the Problem Means

In South Africa, loadshedding causes sudden power loss to:

- Your ONT
- Your router
- Street-level fibre cabinets (in some areas)

Many users assume that power outages damage fibre lines. This is incorrect.

Fibre cables transmit optical light signals and are not affected by grid electricity in the way copper cables are. However, power instability can affect the ONT device and network re-registration.

Understanding the difference prevents unnecessary FNO escalation.

## What Loadshedding Actually Affects

1. ONT Reboot Cycle

When power cuts:

- ONT turns off
- Optical session drops
- Upon power return, ONT re-registers (PON flashing)

> **INFO:** This is normal behaviour.

2. Registration Delays

If many homes reboot simultaneously:

- Access-layer registration queues may temporarily increase
- PON may flash longer than usual
- Sync may take up to 5–10 minutes

This is not fibre damage.

3. Power Surge Risk

The real risk is not loadshedding — it is power surge on restoration.

Surges can:

- Damage ONT power adapters
- Cause unstable voltage
- Prevent ONT from powering on properly

> **WARNING:** If Power light remains off after outage, test another power source.

## Cause vs Effect Table

| Event | What Happens | Fibre Damage? | Action |
| --- | --- | --- | --- |
| Normal loadshedding | ONT turns off | No | Wait for power return |
| Power restoration | ONT reboots, PON flashes | No | Allow 5 minutes |
| Voltage surge | ONT fails to power on | No fibre damage, device risk | Check adapter |
| Persistent red LOS after outage | Signal lost | Not caused by loadshedding | Escalate access-layer fault |

## Step-by-Step After Loadshedding Checklist

1. **Check Power Light**
   - If off → confirm adapter or UPS output.
2. **Allow Full Boot Cycle**
   - Wait 5 minutes without interruption.
3. **Check PON Status**
   - Flashing → normal re-registration.
   - Solid → connection restored.
4. **Check LOS**
   - Red after full boot → possible access-layer fault.
5. **Avoid Rapid Restarting**
   - Follow correct ONT restart process once if needed.

> **INFO:** If LOS remains red beyond 10 minutes, escalation may be required.

## Definition: Optical vs Electrical Infrastructure

- **Optical Infrastructure** — Fibre infrastructure uses optical light pulses, not electrical current, to transmit data.
- **Electrical Impact** — Loadshedding affects electrical supply but does not travel through fibre cables.
- **Device-Level Damage** — May occur from voltage instability, but fibre lines themselves are not electrically harmed.

## South African Context: Cabinet Power

Some fibre cabinets include battery backup. During extended loadshedding:

- Cabinet batteries may deplete
- Area-wide outages may occur
- Service restores once cabinet power returns

This is temporary and does not indicate fibre damage.

## When to Escalate

Escalate when:

- ONT has stable power
- PON does not stabilize after 10 minutes
- LOS remains red
- Neighbours are also offline

Typical South African repair timelines:

- 24–48 hours for isolated signal faults
- Up to 72 hours for fibre break investigation

Loadshedding itself is not grounds for fibre repair unless physical infrastructure was damaged separately.

## When This Is NOT the Issue

If all of the following are true, this is not your fault domain:
- PON is solid
- LOS is off
- Internet works but is slow

Then the issue is not related to loadshedding or signal interruption.

## Frequently Asked Questions

**Can loadshedding burn my fibre cable?**

No. Fibre carries light, not electrical current.

**Can power surges damage my ONT?**

Yes. Voltage spikes can damage power adapters or ONT hardware.

**Why does my internet take longer to reconnect after loadshedding?**

Mass simultaneous re-registration can extend PON flashing time.

**Should I unplug the ONT during loadshedding?**

Optional, but using surge protection or stable UPS is safer.

**Why is my LOS red after power returns?**

This likely indicates a separate access-layer signal issue, not power loss itself.