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Circuit Breakers for Industry 4.0

One of the most common issues with circuit protection is over current situations. Typically, the solution to this is incorporating a circuit breaker, or a fuse into the circuit. This is to prevent excessive current overloads flowing down the circuit and damaging components.

The choice between fuses and breakers is a big talking point between electrical designers. It largely boils down to the application. Circuit breakers are easily reset after being tripped, however, this comes at a premium. Fuses, however, are dirt cheap but can take longer to replace and can require higher labour costs and downtime.

Fuses are very simple. They were patented by Thomas Edison in 1890. The most common form is a metal wire or filament enclosed in a glass or ceramic and metal casing. In the event of an overload, the filament melts, and breaks the flow of electricity; hence breaking the circuit. Once a fuse has blown it needs replacing.


Circuit breakers work in a similar way to fuses. The difference is that breakers don’t need to be replaced every time it is tripped. When circuit breakers open, current continues to flow for a short time by arcing across open contact points. Minimising arcs is important for two reasons:

  1. Arcing can damage the contacts.
  2. The arc can ionize gases within the breaker frame. An arc over a long period of time increases pressure which can result in catastrophic failure.

There are many different types of circuit breakers, each with their own methods of tripping and arc management:

  • Magnetic-hydraulic – Used in abnormal site conditions, i.e. high or low temperatures or moisture. These breakers are typically used in marine environments, transportation, and generator rooms; where conditions are extremes. Fluid cylinders are used to dampen mechanical actuators when tripped.
  • Low voltage
  • Medium voltage
  • High voltage
  • Air Circuit – Uses air to quench any arc at atmospheric pressure.
  • SF6 – Current carrying contacts operate in sulphur hexafluoride gas which is a great electrical insulator.
  • Vacuum – Uses a vacuum to extinct arcs.
  • Minimum and Bulk Oil breakers – Contacts are submerged in oil due to its insulating and cooling properties. These breakers are largely obsolete now due to high maintenance requirements.

Schneider Electrics new GV4 range of circuit breakers are available with 2 types of protection.

  • Magnetic
  • Thermal Magnetic

Magnetic breakers make use of a solenoid (electromagnet), that when turned on, allows current to flow across the breaker terminals. If the current reaches excessive levels, the magnetic field will be strong enough to switch a magnetic lever in the mechanism, breaking the current. The breaker can then be reset with a switch.

Thermal magnetic breakers use both electromagnetic circuit breaking and bimetallic strip trip techniques. This has the advantage of reacting instantly to large current surges or short circuits whilst the bimetallic strip reacts to extended current surges over time. The thermal part offers the flexibility of an inverse time response that allows for small overloads over periods of time; as opposed to instantly tripping. This time delay provided by the thermal sensors allows for real-time automated adjustments that can prevent trips, and relay information to drives.


Advances in NFC proximity sensing means that you can now use smartphones for accessing settings, alarms history, and fault differentiation. Connected products are the future of industry and automation.

For more information on Schneider electric GV4 range, please visit

Written by Mark Collings - Graduate at Schneider Electric

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