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Free AI-Powered Electrical Calculators – Size Equipment & Forecast Energy Costs

Use our free AI tools to accurately size transformers, wires, and motors. Forecast electricity procurement costs and optimize energy budgets in seconds.

Sizing the circuit breaker

This tool calculates the rating of protective devices (circuit breakers) for electrical circuits according to IEC 60364-4-43, providing protection against overloads and short circuits. Suitable for industrial, commercial, and building electrical design. Parameter Description Current Type Select the type of current in the circuit: - Direct Current (DC) : Constant flow from positive to negative pole - Alternating Current (AC) : Reverses direction and amplitude periodically at constant frequency System configurations: - Single-phase: Two conductors (phase + neutral) - Two-phase: Two phase conductors; neutral may be distributed - Three-phase: Three phase conductors; four-wire system includes neutral Voltage Electric potential difference between two points. - For single-phase: Enter Phase-Neutral voltage - For two-phase or three-phase: Enter Phase-Phase voltage Load Power to be considered when determining the characteristics of circuit components. Power Factor Ratio of active power to apparent power. Formula:cos φ = P / S where φ is the phase angle between voltage and current. Value ranges from 0 to 1. Method of Installation Installation method as defined in IEC 60364-5-52 (Table A.52.3). Examples include: - Free air - In conduit - Underground - Multiple circuits in a common duct Note: Not all installation methods are recognized in every country's regulations. Ambient Temperature Temperature of the surrounding medium when the conductor is not loaded. Affects current-carrying capacity; commonly referenced at 30°C or 40°C. Conductor Material of the conductor used: - Copper - Aluminum Different materials have different resistivity and current-carrying capabilities. Insulation Temperature rating of the insulation material: - PVC (Thermoplastic): 70°C at conductor - XLPE or EPR (Thermosetting): 90°C at conductor Higher temperatures reduce insulation performance and require derating. Wire Size Cross-sectional area of the conductor, typically in mm². Determines the maximum allowable current. Phase Conductors in Parallel Conductors with the same cross-sectional area, length, and material can be connected in parallel. The maximum permissible current is the sum of individual-core maximum currents. Circuits in the Same Conduit Number of lines inside the duct powering different loads (e.g., 2 lines for 2 motors). Reduction factors apply based on IEC 60364-5-52 Table B.52.17. Total Harmonic Distortion (THD) Total content of 3n harmonic current. If the value of total 3n harmonic distortion is unknown, use the total harmonic distortion value. High THD increases neutral current and affects breaker sizing. Protection Device Device responsible for protecting the cable from overload and short circuit, such as a circuit breaker or fuse. All Parallel Cables Are in a Single Conduit Check this option if all sets of parallel cables are installed in one duct (derating factor will be applied). Uncheck if each set is installed in a separate duct. Definition: One "set" consists of one conductor per phase + one neutral conductor (if required) + one protective conductor.

Dimensions and weight of cables

A reference guide for electrical cable specifications including type, size, diameter, and weight. "Cable dimension and weight data are essential for selecting conduit size, planning installations, and ensuring structural safety." Key Parameters Cable Type Unipolar: consisting of a single conductor. Bipolar: consisting of 2 conductors. Tripolar: consisting of 3 conductors. Quadrupolar: consisting of 4 conductors. Pentapolar: consisting of 5 conductors. Multipolar: consisting of 2 or more conductors. Common Cable Standards Code Description FS17 PVC insulated cable (CPR) N07VK PVC insulated cable FG17 Rubber insulated cable (CPR) FG16R16 Rubber insulated cable with PVC sheath (CPR) FG7R Rubber insulated cable with PVC sheath FROR PVC insulated multipolar cable Wire Size Cross-sectional area of the conductor, measured in mm² or AWG. Determines current-carrying capacity and voltage drop. Larger sizes allow higher currents. Common sizes: 1.5mm², 2.5mm², 4mm², 6mm², 10mm², 16mm², etc. Conductor Diameter Total diameter of the strands of wires within the conductor, measured in millimeters (mm). Includes all individual strands twisted together. Important for terminal compatibility and connector sizing. External Diameter Outside diameter including insulation, measured in millimeters (mm). Critical for selecting conduit size and avoiding overcrowding. Includes both conductor and insulation layers. Cable Weight Weight of the cable per meter or per kilometer, including conductor and insulation. Measured in kg/km or kg/m. Important for structural design, support spacing, and transportation. Example values: - 2.5mm² PVC: ~19 kg/km - 6mm² Copper: ~48 kg/km - 16mm²: ~130 kg/km Why These Parameters Matter Parameter Engineering Use Case Wire Size Determine ampacity, voltage drop, and circuit protection Conductor Diameter Ensure proper fit in terminals and connectors External Diameter Choose correct conduit size and avoid overcrowding Cable Weight Plan support intervals and prevent sagging Cable Type Match application needs (fixed vs. mobile, indoor vs. outdoor)

Fuses application categories

A comprehensive guide to understanding fuse classification according to IEC 60269-1. "The abbreviation is made up of two letters: the first, lowercase, identifies the current interruption field (g or a); the second, uppercase, indicates the category of use." — According to IEC 60269-1 What Are Fuse Application Categories? Fuse application categories define: The type of circuit the fuse protects Its performance under fault conditions Whether it can interrupt short-circuit currents Compatibility with circuit breakers and other protective devices These categories ensure safe operation and coordination in power distribution systems. Standard Classification System (IEC 60269-1) Two-Letter Code Format First letter (lowercase): Current interruption capability Second letter (uppercase): Application category First Letter: Interruption Field Letter Meaning `g` General purpose – capable of interrupting all fault currents up to its rated breaking capacity. `a` Limited application – designed for overload protection only, not full short-circuit interruption. Second Letter: Category of Use Letter Application `G` General-purpose fuse – suitable for protecting conductors and cables against overcurrents and short circuits. `M` Motor protection – designed for motors, provides thermal overload protection and limited short-circuit protection. `L` Lighting circuits – used in lighting installations, often with lower breaking capacity. `T` Time-delayed (slow-blow) fuses – for equipment with high inrush currents (e.g., transformers, heaters). `R` Restricted use – specific applications requiring special characteristics. Common Fuse Types & Their Uses Code Full Name Typical Applications `gG` General-purpose fuse Main circuits, distribution boards, branch circuits `gM` Motor protection fuse Motors, pumps, compressors `aM` Limited motor protection Small motors where full short-circuit interruption is not required `gL` Lighting fuse Lighting circuits, domestic installations `gT` Time-delay fuse Transformers, heaters, starters `aR` Restricted use fuse Specialized industrial equipment Why This Matters Using the wrong fuse category can lead to: Failure to clear faults → fire risk Unnecessary tripping → downtime Incompatibility with circuit breakers Violation of safety standards (IEC, NEC) Always select the correct fuse based on: Circuit type (motor, lighting, general) Load characteristics (inrush current) Required breaking capacity Coordination with upstream protection

Electrical symbols

A reference guide to standardized electrical and electronic symbols according to IEC 60617. "An electronic symbol is a pictogram used to represent various electrical and electronic devices or functions in a schematic diagram of an electrical or electronic circuit." — According to IEC 60617 What Are Electrical Symbols? Electrical symbols are pictograms that represent components and functions in circuit diagrams. They allow engineers, technicians, and designers to: Communicate circuit designs clearly Understand complex systems quickly Create and interpret wiring diagrams Ensure consistency across industries and countries These symbols are defined by IEC 60617 , the global standard for graphical symbols in electrical technology. Why IEC 60617 Matters IEC 60617 ensures: Universal understanding — same symbols worldwide Clarity and safety — prevents misinterpretation Interoperability — supports global design collaboration Compliance — required in many industrial and commercial applications Common Electrical Symbols & Their Meanings Symbol Reference Table Symbol Component Description Power Source / Battery Represents DC voltage source; positive (+) and negative (-) terminals indicated AC Supply Alternating current source (e.g., mains power) Resistor Limits current flow; labeled with resistance value (e.g., 1kΩ) Capacitor Stores electrical energy; polarized (electrolytic) or non-polarized Inductor / Coil Stores energy in magnetic field; used in filters and transformers Diode Allows current in one direction only; arrow indicates forward direction LED (Light Emitting Diode) Special diode that emits light when current flows Lamp / Bulb Represents lighting load Transformer Changes AC voltage levels between primary and secondary windings Switch Controls circuit continuity; can be open or closed Relay Electrically operated switch controlled by coil Ground Connection to earth or reference potential Fuse Protects circuit from overcurrent; breaks if current exceeds rating Circuit Breaker Automatically interrupts fault current; resettable Fuse Holder Enclosure for fuse; may include indicator Terminal Block Point where wires connect; often used in control panels Motor Rotating machine driven by electricity Integrated Circuit (IC) Complex semiconductor device; multiple pins Transistor (NPN/PNP) Amplifier or switch; three terminals (Base, Collector, Emitter) How to Use This Guide This web-based reference helps you: Identify unknown symbols in schematics Draw accurate circuit diagrams Learn standard notation for exams or projects Improve communication with electricians and engineers You can bookmark this page or save it offline for quick access during work or study.

Table of resistivity and condctivity

A reference guide for electrical resistivity and conductivity of materials at different temperatures, based on IEC standards. "Calculation of the resistivity and conductivity of a material based on temperature. Resistivity strongly depends on the presence of impurities in the material. Copper resistivity according to IEC 60028, aluminium resistivity according to IEC 60889." Parameters Resistivity Electrical resistivity is a fundamental property of a material that measures how strongly it resists electric current. Conductivity Electrical conductivity is the reciprocal of electrical resistivity. It represents a material's ability to conduct electric current. Temperature coeff. Temperature coefficient of resistance for the conductor material. Temperature Dependence Formula ρ(T) = ρ₀ [1 + α (T - T₀)] Where: ρ(T): Resistivity at temperature T ρ₀: Resistivity at reference temperature T₀ (20°C) α: Temperature coefficient of resistance (°C⁻¹) T: Operating temperature in °C Standard Values (IEC 60028, IEC 60889) Material Resistivity @ 20°C (Ω·m) Conductivity (S/m) α (°C⁻¹) Standard Copper (Cu) 1.724 × 10⁻⁸ 5.796 × 10⁷ 0.00393 IEC 60028 Aluminum (Al) 2.828 × 10⁻⁸ 3.536 × 10⁷ 0.00403 IEC 60889 Silver (Ag) 1.587 × 10⁻⁸ 6.300 × 10⁷ 0.0038 – Gold (Au) 2.44 × 10⁻⁸ 4.10 × 10⁷ 0.0034 – Iron (Fe) 9.7 × 10⁻⁸ 1.03 × 10⁷ 0.005 – Why Impurities Matter Even small amounts of impurities can increase resistivity by up to 20%. For example: Pure copper: ~1.724 × 10⁻⁸ Ω·m Commercial copper: up to 20% higher Use high-purity copper for precision applications like power transmission lines. Practical Use Cases Power Line Design : Calculate voltage drop and select wire size Motor Windings : Estimate resistance at operating temperature PCB Traces : Model thermal behavior and signal loss Sensors : Calibrate RTDs and compensate for temperature drift
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