Modern Electrical Protections: The Importance of Arc Flash Detectors (AFDD)
The evolution of modern electrical protection: Beyond traditional circuit breakers
In the field of electrical installations, safety has taken a quantum leap thanks to the introduction of devices such as Arc Flash Detectors (AFDD). While circuit breakers and differential circuit breakers have been fundamental pillars of electrical protection, AFDDs address a type of fault that traditional systems cannot handle: dangerous electrical arcs. Fires caused in old installations with bad contacts, poor wiring, or where electronic devices coexist where a small diode or capacitor can fail, are the common scenario we see weekly on the news of a catastrophic fire.
What are AFDDs and how do they differ from other devices?
An AFDD (Arc Fault Detection Device) is a device designed to detect specific patterns of dangerous arcing, either in series (within a damaged cable) or in parallel (between conductors). These do not generate sufficient currents to trip a circuit breaker or earth leakage circuit breaker, but can cause fires.
Comparison with traditional devices:
- Circuit breakers (MCB): Act against overloads and short circuits. They do not detect electric arcs in series or parallel that do not exceed their current limit.
- Residual current circuit breakers (RCD): They operate against earth leakage currents, protecting against indirect contacts and electrocution. They are not sensitive to arcing faults that do not involve earth leakage.
- AFDD: Detect dangerous electric arcs by analysing the current signal, disconnecting the circuit before the heat generated causes a fire. Particularly effective in installations with damaged cables or loose connections.
When does each device work?
Why are AFDDs essential in modern installations?
- Risk mitigation in home automation environments: In systems with a high density of electronic devices, such as smart lighting or sensors, wear and tear on cables and connections can lead to electrical arcing. AFDDs complement traditional protections, ensuring the safety of sensitive equipment and people.
- Fire prevention in vulnerable buildings: Wooden buildings, hospitals, hotels and crowded places are scenarios where AFDDs act as a crucial barrier against electrical fires.
- Regulatory compliance and advanced protection: In Spain, although they are not generally mandatory, the ITC-BT-24 of the REBT recommends their use in fire-risk premises, such as warehouses and historic buildings.
A case study: How do they work together?
Imagine an electrical system with a damaged cable behind a wall. This cable starts to arc in series due to insulation wear:
- The circuit breaker does not trip because there is no overload or short circuit.
- The differential circuit breaker does not detect the fault because there is no earth leakage.
- The AFDD identifies the characteristic arcing pattern and disconnects the circuit before the heat generated causes a fire.
Conclusion: Comprehensive safety with complementary protections
AFDDs do not replace circuit breakers or differential circuit breakers, but complement them, covering a critical area of protection that traditional devices do not. In an environment where technology and electrical safety are evolving rapidly, these devices are an essential investment to avoid risks that could have catastrophic consequences.
Are you ready to take the electrical protection of your projects to the next level? Leave us your comments or get in touch to explore the safest and most efficient solutions for your facilities.
Prepared by: Manuel García Jiménez
