How selectivity helps increase the comfort of modern electrical installations

A blackout during a World Championship match? It doesn’t bear thinking about, right? Selective protection devices prevent a complete power failure.

A blackout during a World Championship match? It doesn’t bear thinking about, right? Selective protection devices prevent a complete power failure. But what does selectivity mean?

Imagine you’re about to watch the World Championship soccer quarter-final, and just after the first whistle, the electricity cuts out. Total power failure, throughout the entire apartment. It doesn’t bear thinking about, right?

Well… that already happened in 2008, during the semifinal between Germany and Turkey…
A blackout resulted in six minutes of transmission interruptions. Only the TV commentary was able to carry the audience through this difficult time, which felt like an eternity. Avoiding complete electrical outages is a true art: selective protection devices in electrical distribution boards prevent a complete blackout.

In my opinion, electricity has got to be available at all times and right away in this day and age. “Electricity just comes out of the socket, right?” In private homes, a blackout can be unpleasant and annoying. In business and at production sites, a blackout can quickly lead to mounting costs. But what does selectivity actually mean for circuit breakers?

What is selectivity?

You’ve almost certainly heard the term ‘selectivity’ before in terms of circuit breakers or other protection devices. Selectivity is supposed to ensure that as many components of the electrical circuit remain operational as possible despite a fault, and only the protection element that is installed closest to the fault location is triggered. Selectivity is supposed to be achieved for both overload and short-circuit, especially in end circuits—where, for instance, the TV is connected. As a result, only a small part of the electrical installation is separated from the circuit. Other circuits that are not experiencing a fault continue to be supplied with electricity. That way, you won’t miss the final when your neighbor has a short circuit.

Where is selectivity used?

Selective behavior of protection devices is required almost everywhere. The choice of devices with selective behavior and the installation layout are important for protecting people (RCCB) as well as cables and wiring systems. When planning an installation layout, the distribution of the individual consumer groups on the circuits must be taken into consideration

What are the advantages of selectivity?
In electrical installations, selectivity:

• Ensures safety of the installation and people at all times, due to the fact that circuits of safety mechanisms are not unnecessarily switched off.
• Reduces the extent to which equipment is affected
• Minimizes damage to or stress on components
• Safeguards high availability of an electrical installation (minimizes downtime)
• Provides high service security
• Allows faults to be located and rectified quickly, as only a small part of the installation is switched off

The importance of selectivity is only obvious after the example of the Championship finals match. The good news: You or your electrician no longer need to make any calculations, compare tables or just simply hope for the best when it comes to circuit breakers in distribution and end circuits.

Simple solution for distribution and end circuits

The S750 and S750DR type series selective main circuit breakers are the solution for existing selectivity problems, and, thanks to their innovative technology, provide future-oriented energy distribution with optimal system availability. Their special operating principle allows full selectivity for downstream circuit breakers. Their special construction also provides a reliable protection function, independent of system incidents or network configuration.

If only we’d known before the Championships, right? Well, at least it’s still in time for the World Cup! That gives you plenty of time to have your electrical services converted so that you don’t suffer any blackouts during the 2018 finals.

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About the author

Florian Krackhecke

Ich arbeite bei ABB im Bereich der Niederspannungsprodukte als Produktmarketingmanager für Installationsprodukte. Meine Aufgabenschwerpunkte liegen in der Lebenszyklusbetreuung von Sicherungsautomaten und unserem Stecksockelsystem Smissline TP. In diesem Zusammenhang erstelle ich den richtigen Marketing Mix und unterstütze das operative Tagesgeschäft. Am liebsten erkläre ich jedoch meine Produkte, informiere mich auf Messen und Veranstaltungen über neue Trends, Produkte, Anwendungen und Lösungen im Rahmen der Energieeinspeisung und Verteilung von Niederspannungsanlagen.
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