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Understanding Heat Load Calculations in Switchboards
Introduction Heat is a critical factor in the failure of electronic components within switchboards, with a big impact on their longevity and reliability. When the temperature inside a Switchboard exceeds the maximum permitted operating temperature by 10 Kelvin, the service life of these components is effectively halved, while their failure rate doubles. 💨 If natural […]
Understanding AC Induction Motor Starting
Introduction Just to be clear from the beginning, a three-phase induction motor is self-starting. When the supply is connected to the stator of such a motor, a rotating magnetic field is produced. This causes the rotor to begin rotating, effectively starting the motor. However, it’s important to note that the starting current at this stage […]
Understanding Induction Motors Nameplate
Introduction A motor nameplate is like the ID card for an electric motor, and it’s glued or bolted right onto it. This nameplate has all the key details you need for setting up a new system, doing regular upkeep, or fixing problems. It tells you what the motor can do, how to use it correctly, […]
Understanding Cable Pathways, Cable Conduits, Cable Trays, Cable Pits
Introduction A cable pathway or raceway is a protective channel or enclosure made of materials like metal or plastic, used to manage and safeguard electrical cables and wires. It serves to organize and shield cables from physical damage, environmental elements, and interference. There are various types, including surface-mounted, flush-mounted, and underground pathways, each suited to […]
Understanding Power Cable Sizing, AS/NZS3008
Introduction In electrical engineering design and installation, choosing the right cable size is important. It’s not just about ensuring power flows efficiently, but also about safety, compliance, and reliability. Opt for a size too small, and it’s non-compliant and unsafe; go too big, and it’s simply a waste of resources. This is where AS/NZS3008, the […]
Understanding Surge Protection Devices (SPD), AS/NZS3000
Introduction Surge protection devices (SPD) offer protection against overvoltage, typically arising from lightning strikes at installation or from the electricity grid and telecommunication network. While the installation of an SPD is not mandated by the Australian standard AS/NZS3000, it is included in the standards for informational purposes. However, there may be instances where it is […]
Understanding Overcurrent Circuit Protection, AS/NZS3000
Introduction In electrical systems, active conductors are protected by fuses or circuit breakers, which are sized to automatically disconnect the power supply in cases of overcurrent. This is important for preventing injury to individuals or livestock. These devices can also act as points of isolation. Fuses are not normally installed in neutral conductors. The installation […]
Understanding LV segregation, AS/NZS3000
Introduction The Australian standard AS/NZS3000 or wiring rules provides guidance on how to segregate systems operating at different voltages that share common wiring pathways, as well as how to segregate between electrical and non-electrical services sharing pathways. ⚡️ AS/NZS 3000 walks us through voltage diversity and shared wiring paths. High Voltage + Low/Extra Low […]
Understanding Type 1 and Type 2 Cordination
Introduction The International Electrotechnical Commission (IEC) has come up with a criteria for the short circuit performance of contactors and starters, known as Type 1 coordination and Type 2 coordination. These terms define the protection levels of motor controllers in the event of a short circuit fault. To meet these standards, a motor controller (contactor […]
Understanding Ingress Protection (IP) Ratings
Introduction Ingress Protection (IP) ratings measure how resistant a device is against solids and water. IP ratings are determined by the international standard EN 60529 (British BS EN 60529:1992 – Degrees of protection provided by enclosures (IP Code) and European IEC 60509: 1989 – Degrees of protection provided by enclosures (IP Code). The first edition of IEC […]
Understanding Why Switching the Neutral Conductor is a bad idea, AS/NZS3000
Introduction In AS/NZS3000, it’s specified that switching the neutral conductor of consumer mains is not allowed. This applies similarly where the neutral conductor is used as a combined protective earthing and neutral (PEN) conductor for protective earthing of any portion of an electrical installation. “⚡⚠️ Important lesson from AS/NZS 3000: Never switch the neutral conductor […]
Understanding the MEN system, AS/NZS3000
Introduction The Multiple Earthed Neutral (MEN) earthing system, used in Australia and New Zealand, involves grounding the neutral conductor (PEN) of the distribution system at regular intervals starting from the source of supply and continuing throughout the entire system, including every connected electrical installation. Within each electrical setup, the earthing system is separate from the […]
Understanding The Consumer Mains Cable, AS/NZS3000
Introduction In this blog post, we’ll take a closer look at the different components of a facility’s distribution network: the consumer mains, submains, and final subcircuits. We’ll focus more on consumer mains. While the wiring rules do give some guidance on what’s needed, the finer details often depend on your local utility. So, it’s a […]
Understanding Transformer Vector Groups
Introduction A vector group is the International Electrotechnical Commission (IEC) method of categorizing the primary windings and secondary winding configurations of three-phase transformers. The vector group designation indicates the windings configurations and the difference in phase angle between them. This naming convection is done by the IEC though their standard IEC 60076-1. Understanding transformer vector […]
Understanding Arcflash Assessment
Introduction An arc flash is a sudden and dangerous release of electrical energy that poses a serious risk of injury or even death to individuals exposed to it. This event occurs when insulation breaks down between two conductive surfaces of different electrical potential, often within a high-voltage or low-voltage electrical system. This breakdown creates a […]
Understanding Transformer Cooling
Introduction Transformers are among the most efficient electrical devices, with most of them having full load efficiencies ranging between 95% and 98.5%. During normal operation, transformers produce a slight amount of sound and heat. The heat is due to copper losses in the windings and iron losses in the core. Eventually, the generated heat needs […]
Understanding Short Circuit Fault Calculations
Introduction Electrical installations always require protection against short-circuits and/or overloads. According to industry standards, an overcurrent protective device, protecting against both overload and short-circuit currents, must be positioned at the origin of every circuit and at any point where a reduction occurs in the current carrying capacity of the conductors. The short-circuit current must be […]
Understanding Power Cable Insulation
Introduction We have all, at some point, held a live electrical cable and not received an electrical shock. Magic, right? Well, this is because of the cable’s insulation. Insulation is an important non-conductive material that surrounds and protects the individual wires or conductors. It resists electrical leakage and preserves the material integrity of the conductor […]
Understanding Switchboard Access, AS/NZS3000
Introduction Today we are going to talk about the requirements contained in the standard AS/NZS3000 around access to switchboards. As previously discussed, a switchboard is an assembly of circuit protective devices, with or without switchgear, instruments or connecting devices, suitably arranged and mounted for distribution to, and protection of, one or more submains or final […]
Understanding the Power Triangle
Introduction The power triangle is a graphical representation that aids in understanding the relationship between active power, reactive power, and apparent power in an electrical system, all of which are explained below. It serves as a valuable tool for engineers and technicians working with power systems, providing a visual representation of the power flow in […]
Understanding Low Voltage Earthing Systems
Introduction The fundamental rule for protection against electric shock is that hazardous live parts must not be accessible, and likewise, accessible conductive parts must not be hazardous—neither under normal conditions nor under single fault conditions. Protection under normal conditions is provided by basic protective provisions, while fault protective provisions handle single fault conditions. Alternatively, an […]
Understanding Power Factor in Power Systems
Introduction Power factor is a term used in electrical engineering to describe the ratio of Real Power (W) to Apparent Power (kVA) in an electrical circuit. It is a measure of how effectively electrical power is being converted into useful work output. The Power Triangle We have previously discussed three phase power and the power […]
Understanding Switchboard Form of Separation, AS/NZS61439
Introduction Switchboard form of segregation or, correctly according to AS/NZS 61439, form of separation refers to the separation of functional units and busbars within an Assembly, as specified by AS/NZS 61439. The standard specifies four main types of separation methods: Form 1, Form 2, Form 3, and Form 4. Each type also has further subdivisions, […]
Understanding Voltage Drop, AS/NZS3008
Introduction Voltage drop occurs in electrical circuits and systems where the voltage level at a specific point is reduced as current flows through conductors. This reduction in voltage happens due to the inherent resistance of the materials used as electrical conductors. Voltage drop can lead to several consequences such as: “ Exploring Voltage Drop Discover how […]
Understanding Maximum Demand, AS/NZS3000
Introduction According to the Australia wiring rules book AS/NZS3000 the maximum demand is the maximum current which the consumer mains or submain conductor can carry for a sustained period without overheating. Why is it important? 🏡 At home, maximum demand matters too! From running appliances to charging gadgets, our energy consumption impacts the grid. Learning […]
Understanding Miniature Circuit Breaker (MCB) Types and Tripping Curves
Introduction Miniature circuit breakers (MCB) provide protection against short circuits and are rated normally up to 125A. They can be combined with a residual current device, to provide protection against short circuits, overloaded circuits and ground faults. MCB’s tripping characteristics are represented graphically in a trip curve. The curve shows the response of the thermal and magnetic trip […]
Understanding Earth Fault Loop Impedance, AZ/NZS3000
Introduction When it comes to designing electrical systems, safety should always be the number one priority. One critical aspect that plays a vital role in protecting people and property from electrical faults is the earth fault loop impedance. In this blog post, we will explore what earth fault loop impedance is, why it’s important, and […]