Reticulation Design & Fault Level Safety
Protecting Your People, Your Equipment, and Your Business
In any industrial electrical system, the biggest danger is not a shock or a loose wire — it’s an arc flash.
An arc flash is a violent electrical explosion that can happen when someone switches a breaker back on while a fault is still present. It releases extreme heat, bright light, and explosive pressure in a fraction of a second.
This is why reticulation design and fault level audits are not optional. They are essential safety measures that protect your staff from life changing injuries.

What Is Fault Level — In Plain English
Every electrical system has a “fault level.”
This is the maximum amount of energy the system can release if a short circuit occurs.
Think of it like water pressure:
• High pressure = a burst pipe
• Low pressure = a manageable leak
Electrical systems behave the same way.
If the fault level is high, a short circuit can release enough energy to:
• Blow apart a breaker
• Damage a distribution board
• Cause a severe arc flash in someone’s face
Knowing the fault level is the only way to design a system that can safely handle a fault.

Where the Fault Level Comes From
As an example, imagine your supply comes from a generally small 330 kVA, 3 phase transformer with a 6% impedance. It could be less as well.
In simple terms:
This transformer can deliver almost 8000 Amps during a fault at the transformer, enough to cause and arc flash and explode a breaker, if it is not matched for this transformer.
Also imagine you have a 50 metre, 50 mm² armoured cable feeding your plant or distribution board.
Even at the end of that cable, the available fault energy is nearly 5000 Amps, if not matched for this cable it can:
• Destroy equipment
• Cause an arc flash
• Injure an employee resetting a breaker
• Reduce life cycle or damage the cable permanently
This is why accurate reticulation design is essential.

Why Reticulation Design Matters
A proper reticulation design ensures that:
1. Breakers can safely interrupt the maximum fault energy
At the Transformer, the breaker selected must be able to trip fast enough and are capable of surviving a short circuit in the cable or just after the breaker, without exploding and causing a arc flash when it is reset. If a breaker is under rated, it can explode instead of tripping.
2. Cables can handle the heat of a fault
Incorrect cable sizing increases fire and equipment failure risk.
Each cable also has a manufacturer maximum short circuit characteristic. Cables are expensive and a cable can only deal with so many short circuits before being destroyed.
3. Protection devices trip fast enough to prevent arc flash
The faster the trip, the lower the incident energy. The higher the transformer short circuit current potential, the faster the breaker must trip.
4. Your system complies with SANS 10142 1
This protects your business legally and operationally.

Why a Fault Level Audit Is Critical
A fault level audit is not a technical luxury — it is a life safety assessment.
It answers the most important question:
“If someone resets a tripped breaker, will they be safe?”
A proper audit will:
• Measure the real fault levels at each point in your plant
• Identify equipment that is under rated or unsafe
• Highlight panels with high arc flash risk
• Recommend corrective actions
• Prevent catastrophic failures and injuries
Most importantly:
It ensures no employee ever has to experience an arc flash in their face when switching a breaker back on.

E Square Electrical Solutions: Engineering for Safety
Our reticulation design and fault level audits include:
• Full transformer and cable fault analysis
• Fault level calculations at every DB
• Protection grading and coordination
• Arc flash risk identification
• SANS 10142 1 compliance verification
• Clear recommendations for safe operation
We design electrical systems that are safe, predictable, and built to protect your people.

cobus@e2electrical.co.za & 0824442347