Guides & Engineering Reference
Read beginner-friendly lessons to understand the engineering, or use the reference handbook for fast technical lookups.
Engineering Reference
Search standards, ANSI/IEEE relay function numbers, electrical equations and SI prefixes without opening a full lesson.
Open the reference library →Educational guides
Illustrated explanations, worked examples and practical engineering notes.
- Electrical Fundamentals · 2
- Cables & Distribution · 6
- Power Systems · 5
- Power Quality · 2
- Motors & Industrial · 3
- Protection & Safety · 3
- Renewable Energy · 1
- Greece: grid & regulations · 2
Electrical Fundamentals · 2
Ohm's Law Explained
Understand voltage, current, resistance and power through an electrical circuit diagram, V-I graph, equations and worked examples.
Read the full guide →AC Power Explained: P, Q, S & Power Factor
What kW, kvar and kVA mean, how the power triangle works, current/voltage phase diagrams, cos φ, single-phase vs three-phase and worked examples.
Read the full guide →Cables & Distribution · 6
Voltage Drop Explained
Why voltage decreases along cables, R and X, operating temperature, power factor, circuit types, formulas and worked examples.
Read the full guide →LV Cable Sizing Explained
Installation ratings, temperature/grouping derating, parallel conductors, breaker coordination, voltage drop, adiabatic fault checks and how to choose the neutral conductor.
Read the full guide →MV Cable Sizing Explained
How 20 kV XLPE cables work, flat burial versus underground ducts, thermal ampacity, conductor faults and metallic screens.
Read the full guide →PE Conductor Sizing Explained
IEC 60364-5-54 table and adiabatic thermal method, k factors, installation conditions and practical examples.
Read guide →LV Busbar Sizing Explained
Rectangular copper/aluminium bars, transformer kVA, cross-sectional area, adiabatic fault heating, IEC 61439 temperature-rise verification and peak short-circuit forces.
Read the full guide →Cable Tray Fill Explained
Single-row width from cable outside diameters, gaps and reserves, and why there is no universal IEC fill percentage.
Read guide →Power Systems · 5
Transformer Fundamentals & Calculations
The laminated magnetic core, Faraday induction, cast resin vs oil insulation, Dyn5/Dyn11 vector groups, HV/LV currents and simplified fault levels.
Read the full guide →LV Short-Circuit Fundamentals
Transformer and feeder impedance, IEC 60909 boundaries, fault current screening and fault-duty checks.
Read guide →Transformer Loss & Energy Cost Explained
No-load and load losses, the x² law, annual energy and cost, and why the average loading must not simply be squared.
Read guide →Transformer Tap Adjustment Explained
How MV taps change the LV voltage, the ratio estimate from a measurement, and the off-circuit safety boundary.
Read guide →UPS & Battery Sizing Explained
W and VA, sizing headroom, the energy for a backup time, and why runtime charts decide.
Read guide →Power Quality · 2
Power Factor Explained
What cos φ means, leading and lagging current, the power triangle, kvar correction, capacitor-bank sizing and worked examples.
Read the full guide →Capacitors, Reactors & L-L Measurements
Delta/star connection diagrams, terminal C/L measurements, ideal reactance, kvar estimates and practical capacitor-bank testing precautions.
Read the full guide →Motors & Industrial · 3
Motor Current & Starting Methods
Rated line and delta winding current, DOL, star-delta, soft starter and VFD figures, and what each one really means.
Read guide →Soft Starter Sizing Explained
The continuous current to look for, the assumed current-limit setting, and why duty and acceleration need manufacturer data.
Read guide →VFD Sizing Explained
Output-current sizing, light-overload and heavy-duty ratings, derating, and motor-side versus mains current.
Read guide →Protection & Safety · 3
CT & VT Sizing Explained
Ratios, burden, 1 A against 5 A, measuring and protection classes (0.2S, 5P10, 3P/6P), ALF and safety.
Read guide →MV Transformer Protection Settings Explained
Rated and LV short-circuit currents seen at MV, illustrative 50/51/50N/51N pickups, IEC curves and the ABB REF615 Start value. Reference only, not for commissioning.
Read guide →Insulation Resistance PI/DAR Explained
Timed insulation-resistance readings, the polarization index and the dielectric absorption ratio, and their limits.
Read guide →Renewable Energy · 1
Greece: grid & regulations · 2
Electrical Installation Inspections in Greece
Categories A, B and Γ, inspection intervals and the installer declaration (ΥΔΕ) under Greek decision 101195/2021. Summary in English, full guide in Greek.
Read summary →Standard HEDNO Supply Sizes in Greece
The standard low-voltage supplies of the Greek distribution operator: kVA, meter fuse and consumer panel fuses. Summary in English, full guide in Greek.
Read summary →How to read the results
Every KiloVolt calculator reports checks in the same way, so you can tell at a glance what has been shown, what has not been checked, and what you still have to verify yourself.
Status badges
- Pass The check was calculated from the data you entered and the limit was met. It is a screening result, not an approval.
- Warning The calculation is valid but something deserves your attention, for example an advisory rating shortfall.
- Fail A limit was exceeded or a required condition is not met. Change the design or the inputs.
- Not assessed The calculator could not check this because data is missing or the method does not cover it. Not assessed is never a pass. Supply the missing data or verify it another way.
- Provisional Every check that could be made was met, but the result still depends on assumptions and data you must confirm. It is not a design approval.
Notices below the results
- Correct these inputs (red): a value is missing or impossible, so no reliable result can be shown. The message names the field as it appears on screen.
- Check before relying on this result (amber): an assumption, missing datum or finding that changes how the result must be read.
- Scope and assumptions (collapsed): what the method always includes and excludes, for example that a short-circuit screen does not include motor contributions. These are always true for the tool, so they are collapsed to keep the amber notice meaningful. Open them whenever you rely on a number.
Each calculator's guide explains its own limits in detail. Back to the guide directory.