Medium Voltage Fuses

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Fuse Products

• For all orders over $100 (excl. GST & freight), freight is FIS (Free into Store).
• For all orders under $100 (excl. GST & freight), a freight charge of $25 + GST is applicable.
• Additional fees may apply for deliveries to the Northern Territory and remote areas.

All Other Products

• Freight charges POA (Price on Application)
• FOT (Customer nominates own carrier and accepts all charges)

Freight details

Fuseco can help! We provide a 24 hour 7 day a week service for customers who are experiencing a breakdown situation or need a fuse urgently after-hours or during the weekend.

To use this service, please call our after-hours number 0411 104 363 and one of our customer service team members will be available to assist you. Please note that an after-hours fee applies to this service.

Medium voltage fuses are defined as fuses with a voltage rating greater than 1,500V and less than or equal to 36,000V (36kV). MV fuses are primarily used for the protection of transformers, motors, CT’s and VT’s. They are very common in electrical systems and they come in diverse styles, shapes and sizes. The most common styles in Australia & NZ are DIN style, British Standard Air and British Standard Oil type. MV fuses are available in three IEC performance categories: Back Up, General Purpose and Full Range.

Fuses are primarily designed to protect equipment from two dangerous electrical events. They are (1) Overloads, and (2) Short Circuits (also known as ‘faults’). In the case of an overload, the current rises above the normal operating current and if it stays there for a period of time, the fuse element melts and the fuse opens the circuit. In the case of a short circuit, the current rise is of such magnitude and speed that a fuse usually opens the circuit very quickly. All quality fuses will be triggered by such events and should open their respective circuit. This is the traditional & common application of the fuse.

However, certain circuits can experience another event which has proven to be extremely dangerous…..temperature rise.

With many high voltage fuse applications, the temperatures can be several 100°C and this can normally be absorbed by the fuse link and the switchgear. However, in some circumstances, the core temperature of the fuse can rise very slowly. Some of the causes of excessive temperature rise include:

• Fuse links switch a fault current below their minimum breaking current. 
• Faults between the windings in the transformer can cause a long lasting fault current. 
• The transformer is operated above its capacity limit. 
• The fuse rated current chosen for transformer protection is too small. 
• Poor contacting. 
• Fuse link current carrying capacity can be reduced due to transient influences damaging individual elements of the melting element system. 
• A lack of air convection or poor switchgear heat dissipation.
• Other factors causing a very slow rise in the circuit current over a long period of time.

This situation can be disastrous because the fuse element could slowly melt while not separating (arcing) to open the circuit. Molten metal can still conduct electricity so the fuse will remain conducting, but the element has melted and has warped from its original design, thus not able to operate as a heat sensitive circuit protection device. If the current continues to rise slowly, the equipment is unprotected by the fuse, possibly leading to a catastrophic situation. Alternatively, if the circuit does experience an over-current after the fuse element has melted, the performance of the fuse will be unpredictable and unreliable. Furthermore, on-going heat stress significantly stresses and ages switchgear equipment.

During testing to IEC420, SIBA thought that it would be highly advantageous to reduce the temperature during and after a current interruption to protect the switchgear. SIBA have done two things to deal with this potential situation.

(1) SIBA have developed a melting activator that has reduced the internal operating rupture temperature of the fuse from 960°C to a much cooler 230°C. Now, the opening of the switchgear is no longer caused by the arcing of the melting element but the striker pin mechanism is triggered by the Melting Activator which in turn acts on the 3 pole trip-free release of the switchgear.

(2) The development of the melting activator has allowed the use of a new type of temperature limiter device in the fuse to activate a striker pin, which in turn operates the relay that protects the asset. This temperature limiter mechanism is a technology that is unique to the SIBA brand and has rapidly become the first choice for electrical engineers around the world. The operating points of the temperature limiter are in a range where temperature rises last longer than 10 minutes.

Incidentally, some high voltage fuse manufacturers still use the old technology of a pyrotechnic device to operate the fuse striker. SIBA believe that a mechanical spring-loaded striker pin system is a far more reliable and effective system and the temperature limiter mechanism has been incorporated into this system.

The Temperature Limiter function, coupled with the fact that all SIBA fuses are manufactured to the highest standards in Germany means that SIBA high voltage fuses represent excellent value and peace of mind. 

There are a number of reasons to choose the SIBA brand for your medium voltage fuse requirements, including the following:

• SIBA high voltage fuses are the ONLY brand to have the integrated Temperature Limiter mechanism. This has been a revelation for companies such as Energex, ETSA, Integral Energy, Western Power, ACTEW and Ausgrid. 
• SIBA fuses are the only fuses that are made in Germany. 
• SIBA have been manufacturing fuses since 1946. Their experience is unsurpassed. 

The DIN design is the most popular style of MV fuse used in the world. Originally designed in Germany, DIN fuses became the default fuses used in electrical systems in Europe and now are a global reference. DIN fuses are characterized by a cylindrical body with 35mm long DIN end caps at either end. DIN fuses are available with the Back Up performance characteristic.

Fuseco is proud to offer the SIBA brand of medium voltage fuses. SIBA is a long established German fuse manufacturer that is widely considered to produce the highest quality MV fuses in the world. SIBA MV fuses have parallel connected pure silver fuse elements, ensuring narrow tolerances of the time/current characteristics. SIBA fuses also contain the SIBA temperature limiter mechanism that protects against inadmissible temperature rises, a unique feature that has become a ‘must have’ choice for many protection engineers. 

The DIN design is the most popular style of MV fuse used in the world. Originally designed in Germany, DIN fuses became the default fuses used in electrical systems in Europe and now are a global reference. DIN fuses are characterized by a cylindrical body with 35mm long DIN end caps at either end. DIN fuses are available with the General Purpose performance characteristic.

Fuseco is proud to offer the SIBA brand of medium voltage fuses. SIBA is a long established German fuse manufacturer that is widely considered to produce the highest quality MV fuses in the world. SIBA MV fuses have parallel connected pure silver fuse elements, ensuring narrow tolerances of the time/current characteristics. SIBA fuses also contain the SIBA temperature limiter mechanism that protects against inadmissible temperature rises, a unique feature that has become a ‘must have’ choice for many protection engineers. 

The DIN design is the most popular style of MV fuse used in the world. Originally designed in Germany, DIN fuses became the default fuses used in electrical systems in Europe and now are a global reference. DIN fuses are characterized by a cylindrical body with 35mm long DIN end caps at either end. DIN fuses are available with the Full Range performance characteristic.

Fuseco is proud to offer the SIBA brand of medium voltage fuses. SIBA is a long established German fuse manufacturer that is widely considered to produce the highest quality MV fuses in the world. SIBA MV fuses have parallel connected pure silver fuse elements, ensuring narrow tolerances of the time/current characteristics. SIBA fuses also contain the SIBA temperature limiter mechanism that protects against inadmissible temperature rises, a unique feature that has become a ‘must have’ choice for many protection engineers. 

Industrial fuses made to BS88 standards are very popular in countries like England, Australia and South Africa. The industrial versions are characterised by either clip-in tags, offset tags or centre tags. To install them in their holders, the usual practice is to screw the fuse to the inside of the fuse holder wedge which then slides into the holder base. British standards (eg. BS1361) also cover service fuses and J-Type fuses.

Motor protection fuses are specially designed for use in a motor circuit (according to IEC 60644) and are available in DIN standard and British Standard design, providing great choice and flexibility to designers of switchboard panels. These fuses provide high reliability against cyclic and peak current loads and incorporate age resistant technology needed to cope with high motor start-up currents. 

They also feature low power losses thus minimising temperature increases in narrow contactor enclosures and low minimum interrupting currents for operation of over-currents in the range 3 - 3.5 times rated current.

Fuseco is proud to offer the SIBA brand of medium voltage fuses. SIBA is a long established German fuse manufacturer that is widely considered to produce the highest quality MV fuses in the world. SIBA MV fuses have parallel connected pure silver fuse elements, ensuring narrow tolerances of the time/current characteristics. SIBA fuses also contain the SIBA temperature limiter mechanism that protects against inadmissible temperature rises, a unique feature that has become a ‘must have’ choice for many protection engineers.