GorkyCAD Pro Blog (English)

Smart home electrical design: what you need to consider

Mon, 25 Aug 2025 00:00:00 GMT

## Smart home — more than gadgets When a client says "smart home", the electrical engineer should think not about voice assistants but about a fundamentally different power supply topology. A smart home is a distributed system with dozens of devices needing power, protection, and communication. Let's break down the key aspects of smart home electrical design. ## 1. Expanded panel A typical apartment panel: 12-24 modules. For a smart home, plan **minimum 36-54 modules**. What's added: - MCBs for automation controllers (separate group) - MCBs for 24V power supplies (LED strips, sensors, actuators) - Socket group inside the panel (router, switch, automation server) - RCBOs for "wet" zones with leak sensors - Contactors for power circuits (relay-controlled) - Space for DIN-rail controllers (KNX, Loxone, Wiren Board) **Rule**: smart home panel — no less than 48 modules. 60 is better. ## 2. Separate automation power Smart home controllers (KNX bus, Loxone, Wiren Board, Home Assistant on Raspberry Pi) need stable 24V DC or 5V DC. Never put them on the same group as power loads. **Solution**: - Dedicated C6 MCB → DIN-rail SMPS 230V→24V DC - UPS for critical automation: clean shutdown on power loss - PoE switch (sensor and camera power over twisted pair) — C6 MCB ## 3. ELV cables and protection A smart home needs a separate ELV panel (or section): - **Twisted pair UTP/FTP Cat 6A**: IP cameras, Wi-Fi APs, PoE sensors, KNX/IP gateways - **KNX cable (2×2×0.8 mm)**: green bus cable, separate from power lines - **Coax RG-6**: TV points (increasingly moving to IPTV) - **Speaker cables**: for built-in speakers **Installation rules (IEC 60364)**: - Minimum 300 mm separation between power and ELV cables - Cross at right angles - ELV cables in separate conduits - Mandatory labeling of all cables ## 4. Redundancy and emergency modes A smart home must not "die" on internet or power loss: - **Basic lighting** (stairs, corridors) — manual bypass (relay modules with manual control) - **Fridge, freezer, server room** — dedicated MCBs with ATS - **Automation UPS**: minimum 30 minutes for clean shutdown - **Generator or PowerWall**: for houses (optional, but plan ATS input) ## 5. Surge and noise protection Controllers and sensors are noise-sensitive: - SPD Class II at input — lightning and switching surge protection - Line filters on controller power supplies - Separation: power cables left, ELV right inside the panel ## 6. Protocol integration: KNX, Zigbee, Wi-Fi, Matter A modern smart home is a protocol zoo. The engineer must plan physical infrastructure: - **KNX**: dedicated twisted pair (green cable), bus topology, up to 700 m - **Zigbee**: no cable needed, but plan router placement every 10-15 m. Specify outlets with built-in Zigbee routers - **Wi-Fi**: ceiling-mounted APs with PoE. One AP per 40-60 m² - **Matter/Thread**: border routers (Apple HomePod, Google Nest Hub) — plan outlets at 1.2 m height ## 7. Documentation Critical for smart homes: - **IP/MAC address map** of all devices - **Group table**: which MCB feeds which consumer - **ELV cable schedule**: type, length, from-to - **Panel photos** before/after wiring with readable labels ## How GorkyCAD helps - Expanded panel with automation section ("Smart Home" template) - Automatic thermal calculation for large panels - ELV section with separate groups and conduits - Documentation export with detailed labeling

How to calculate room illuminance per SP 52.13330 and IS 3646

Wed, 20 Aug 2025 00:00:00 GMT

## Why calculate illuminance Lighting is not "hang a chandelier and done". Insufficient illuminance leads to eye strain, reduced productivity, and even accidents. Excessive — energy waste and discomfort. The electrical engineer must be able to calculate illuminance precisely. In Russia, calculations follow **SP 52.13330.2016**. In India — **IS 3646 (Parts 1-3)**. Both use the utilization factor method. Let's work through a concrete example. ## Initial data Room: kitchen 12 m² (4 × 3 m), ceiling height 2.7 m. Finishes: light wallpaper (walls 50%), white ceiling (70%), porcelain floor tiles (30%). Purpose: cooking, dining — required illuminance 200 lux (SP 52.13330 / IS 3646 for residential kitchens). **Kitchen illuminance standards comparison**: - SP 52.13330: 200 lx (general), 300 lx (countertop work zone) - IS 3646 Part 1: 200 lx (general), 300 lx (work zone) - EN 12464-1: 300-500 lx (kitchen overall) ## Utilization Factor Method Formula: **Φ = (E × S × Ks × Z) / (N × η)** Where: - Φ — required luminous flux per luminaire (lm) - E — required illuminance (lx) = 200 lx - S — room area (m²) = 12 m² - Ks — maintenance factor (accounts for dust and lamp aging) = 1.3 for LED - Z — non-uniformity factor = 1.1 for spot lights - N — number of luminaires - η — utilization factor (determined by room index and reflectance) ## Step 1: Room Index i = (A × B) / (h × (A + B)) Where: - A = 4 m, B = 3 m — room dimensions - h = H - hw - hs = 2.7 - 0.8 - 0.15 = 1.75 m — calculation height i = (4 × 3) / (1.75 × (4 + 3)) = 12 / 12.25 ≈ 0.98 ## Step 2: Utilization factor η From SP 52.13330 tables for cosine-distribution luminaire (Type D) at i ≈ 1.0 and reflectance 70/50/30: η ≈ 0.48 (48% of luminous flux reaches the working plane) ## Step 3: Luminous flux Φtotal = (E × S × Ks × Z) / η = (200 × 12 × 1.3 × 1.1) / 0.48 = 3432 / 0.48 = 7150 lm ## Step 4: Luminaire selection Option 1 — 4 spot lights (N = 4): Φ1 = 1788 lm → LED 1800-2000 lm (≈ 15-18 W each) Option 2 — 2 linear luminaires (N = 2): Φ1 = 3575 lm → LED panels 3600-4000 lm (≈ 30-36 W each) Option 3 — central chandelier (N = 1): Φ1 = 7150 lm → LED 7000-8000 lm (≈ 60-70 W) ## Step 5: Power density check Power density for kitchen: 10-15 W/m². All LED options ≈ 6 W/m² — economical, 2.5-3× better than fluorescent. ## Work zone: local lighting Countertop requires 300 lx. For 2.5 m² work zone and η = 0.5: Φ = (300 × 2.5 × 1.3 × 1.1) / 0.5 = 2145 lm → LED strip 2200 lm (18-20 W) under cabinets. ## What GorkyCAD automates - Calculates room index from floor plan geometry - Selects η from SP/IS/IEC tables - Proposes luminaire placement variants - Calculates total lighting group load - Checks compliance with standards and power density

Voltage drop in real projects — common mistakes

Fri, 15 Aug 2025 00:00:00 GMT

## Why voltage drop matters Voltage drop is the "silent killer" of electrical installations. It doesn't cause instant failures, but consequences accumulate: dim lights, motor overheating, false automation trips, reduced equipment lifespan. Permissible drop per IEC 60364: from main panel to end consumer — **max 5%** (power circuits — 4%, lighting — 3% per some standards). Let's examine three typical design mistakes. ## Mistake 1: Undersized cable for a long run **Situation**: workshop in a private house, 45 m from panel. Loads: compressor (2.2 kW), circular saw (2.5 kW), lighting (0.3 kW). Designer chose 3×2.5 mm² (copper), reasoning: total current 22 A → C25 MCB, 2.5 mm² rated 27 A — fine. **The error**: length wasn't considered. Let's check the drop: - Icalc = 5000 / 230 = 21.7 A (compressor + saw = 4.7 kW) - L = 45 m ΔU% = (2 × 45 × 21.7 × 0.85) / (57 × 2.5 × 230) × 100% = **5.07%** 5.07% > 5% — fails! During compressor start (inrush × 5-7), drop briefly hits 25-30%. **Fix**: cable 3×4 mm² → ΔU% = **3.17%** — passes with margin. Mistake cost: cable replacement + labor ≈ $200+ vs original cable price difference of ~$30. ## Mistake 2: "Forgotten" cable length in conduit **Situation**: open-space office, 25 workstations. Designer calculated drop by straight-line distance from panel to farthest desk (18 m on plan). Actual cable length accounting for rises, drops, and beam bypasses — 31 m. With design length (18 m, Icalc = 10 A, 2.5 mm² copper): ΔU% = **0.99%** — looks great. With actual length (31 m): ΔU% = **1.70%** — still OK but notably worse. Adding vertical runs (±1.2 m per desk through raised floor): 8 desks × 1.2 × 2 = 19.2 m extra. Total: 37.2 m → ΔU% = **2.05%**. **Lesson**: always apply 1.3-1.5× multiplier to plan length for conduit cables. ## Mistake 3: Parallel cables with uneven current distribution **Situation**: 15 kW 3-phase electric boiler, 60 m from panel. Two parallel cables 5×4 mm² (copper) installed — but different lengths (58 m and 63 m, routed differently around obstacles). Currents distribute inversely proportional to resistance (Kirchhoff's law): I1 = 22.8 × 0.276 / (0.254 + 0.276) = 11.9 A I2 = 22.8 × 0.254 / (0.254 + 0.276) = 10.9 A 9% imbalance — cable 1 is overloaded. Copper resistance rises with temperature (+0.4%/°C), imbalance worsens over time. **Fix**: parallel cables must have **strictly equal length** (max 1% difference), same cross-section, same type, identical installation method. Both cables 63 m. ## How GorkyCAD prevents these 1. Auto-calculates voltage drop per circuit segment using actual route geometry (not straight line) 2. Warning + recommendation when > 5% exceeded 3. Parallel cable parameter identity check 4. Calculation with real cable temperature consideration

The future of CAD is in the browser: why desktop is fading

Sun, 10 Aug 2025 00:00:00 GMT

## The desktop CAD era is ending For 40 years, CAD systems were desktop-bound: AutoCAD (1982), SolidWorks (1995), EPLAN, Revit. But the last 5 years have seen a tectonic shift — and it's irreversible. Figma (2012) first proved that a complex engineering tool can work in the browser without performance loss. Onshape (2015) did the same for solid 3D modeling. GorkyCAD (2023) — for electrical power design. ## The technology stack Browser-based CAD became possible thanks to four technologies: ### 1. WebAssembly (WASM) WASM runs code compiled from C/C++/Rust in the browser at near-native speed (90-95%). Heavy calculations — short-circuit currents, ray tracing, topology analysis — now fly in the browser. ### 2. WebGPU A new graphics API (Chrome 113+, Firefox, Safari). Renders complex 2D and 3D scenes with desktop OpenGL/Vulkan-level performance. GorkyCAD uses WebGPU for floor plan and schematic rendering. ### 3. PWAs (Progressive Web Apps) PWAs let web apps work offline, like native apps. Desktop installation, app icon, no address bar. GorkyCAD is a PWA: works without internet, all data stored locally in IndexedDB, syncs when connected. ### 4. Cloud computing Heavy computation can be offloaded to the cloud. GorkyCAD does it locally (WASM), but uses cloud sync for team collaboration. ## Advantages of the web approach 1. **Cross-platform**: Windows, macOS, Linux, ChromeOS, iPad — identical experience everywhere 2. **Instant updates**: no installers, no admin rights needed 3. **Collaboration**: multiple engineers in one project, like Google Docs 4. **Zero deployment**: open browser — start working. Company rollout in 1 day 5. **Security**: data stays in the browser sandbox (without sync enabled) 6. **Accessibility**: no powerful PC required. Project opens on a $150 Chromebook ## What's holding it back - **Habit**: old-school engineers only trust "real" desktop software - **Huge files**: a factory project can be gigabytes — but cloud streaming solves this - **PLM/ERP integration**: historically desktop API-bound — but web APIs are replacing COM/OLE ## Forecast By 2030, 70% of new CAD projects will start in web tools. Desktop will remain in niches: aerospace, automotive (CATIA), microelectronics. The mass market — construction, electrical, HVAC, site planning — will move to the web. GorkyCAD made this bet from day one.

RCD types AC, A, B — differences and when to use each

Tue, 05 Aug 2025 00:00:00 GMT

## What is an RCD An RCD (Residual Current Device) disconnects a circuit when earth leakage current appears. It's the primary protection against electric shock and fires caused by leakage. Operating principle: the RCD measures the difference between phase and neutral currents. In normal operation, Iphase = Ineutral, difference = 0. A leakage through a human body or damaged insulation creates a differential current — the RCD trips in 20-40 ms (at 5×IΔn). BUT: not all RCDs are equal. The type determines what form of leakage current the device responds to. ## RCD Types per IEC 60755 / GOST R 51326.1 ### Type AC Responds **only to sinusoidal AC leakage current**. - Cheapest and most common - Suitable for: incandescent lamps, resistive heating, general socket circuits without electronics - **NOT suitable for**: circuits with SMPS, inverters, dimmers, washing machines, dishwashers, air conditioners, computers ### Type A Responds to **sinusoidal AC + pulsating DC leakage current**. Pulsating DC arises in circuits with half-wave rectification — virtually all modern electronics: SMPS, dimmers, chargers. - **Mandatory for**: washing/dishwashing machines (inverter-controlled motors), air conditioners, computers, server rooms - Recommended by IEC for all residential socket circuits - Price: 30-50% higher than AC ### Type B Responds to **AC + pulsating DC + smooth DC leakage current**. Used where DC leakage is possible: solar inverters, EV charging stations (Mode 3, IEC 61851), VFDs, UPS, medical equipment. - Mandatory for EV charging stations (IEC 61851-1) - Mandatory for transformerless solar inverters - Price: 3-5× higher than AC ### Type F (new) Responds to AC + pulsating DC + mixed-frequency currents (up to 1 kHz). Intermediate between A and B. For single-phase inverter circuits (inverter AC compressors, VFD washing machines). ### Type B+ (newest) Extended B: additionally responds to currents up to 20 kHz. For high-frequency inverters. ## Comparison table | Characteristic | Type AC | Type A | Type F | Type B | Type B+ | |---|---|---|---|---|---| | Sinusoidal AC | ✅ | ✅ | ✅ | ✅ | ✅ | | Pulsating DC | ❌ | ✅ | ✅ | ✅ | ✅ | | Freq. up to 1 kHz | ❌ | ❌ | ✅ | ✅ | ✅ | | Smooth DC | ❌ | ❌ | ❌ | ✅ | ✅ | | Freq. up to 20 kHz | ❌ | ❌ | ❌ | ❌ | ✅ | | Price (relative) | 1× | 1.5× | 2.5× | 4× | 6× | | Typical use | Heaters, lamps | Sockets, appliances | Inverter AC, washers | EV, solar inverters | Medical, industrial VFDs | ## RCD selection for an apartment **Lighting (LED)**: Type A (LED drivers produce pulsating leakage) **Socket circuits**: Type A — mandatory per modern standards **Washing/dishwasher**: Type A (or F for inverter-motor models) **Electric stove**: Type A (electronic controls) **Air conditioner**: Type F (inverter compressor generates mixed-frequency currents) **EV charger**: Type B (IEC 61851-1, mandatory) ## Common mistakes 1. Type AC for the whole apartment — doesn't protect against pulsating leakage, RCD may "go blind" from core saturation 2. Type B where Type A suffices — 4× overpayment 3. Incomer RCD rated too low — nuisance tripping from cumulative natural leakage ## How GorkyCAD helps - Auto-selects RCD type based on consumer composition per group - Recommends Type A/F when inverter-based equipment is present - Warns if Type AC is on a group with a washing machine

GorkyCAD vs EPLAN: honest comparison for designers

Fri, 01 Aug 2025 00:00:00 GMT

## Introduction EPLAN Electric P8 is the de-facto standard for electrical design of industrial facilities in Europe. GorkyCAD Pro is a new web-based tool for electricians and designers. There's a chasm in price, architecture, and philosophy between them. But is the choice that clear-cut? We compare honestly. ## Comparison criteria We evaluated both systems across 15 criteria, grouped into 5 categories: cost, functionality, automation, platform/accessibility, and learning curve. ## 1. Cost - **EPLAN Electric P8**: license from €3,000/year. With Pro Panel, API, P&ID modules — up to €6,000+/year. Deployment: training, server infrastructure, administration — from €10,000 one-time. - **GorkyCAD Pro**: free plan for basic projects, Pro — from ~€10/mo. No hidden modules. Deployment: open browser — start working. **Verdict**: EPLAN is 30-50× more expensive. For a small design bureau or independent electrician, this is the deciding factor. ## 2. Functionality EPLAN covers everything: circuit diagrams, cabinet layout (Pro Panel), hydraulics (Fluid), instrumentation (Preplanning), harnesses (Harness proD). An ecosystem for large manufacturers. GorkyCAD focuses on the electrical designer's tasks: floor plan, single-line diagram, panel layout, BOM, calculations. For industrial multi-line design, GorkyCAD isn't there yet — and we admit it. **Verdict**: EPLAN wins on breadth. GorkyCAD wins in its segment through speed and simplicity. ## 3. Automation - **EPLAN**: powerful macros, C#/Python API, auto-routing, auto-numbering. But setup requires a qualified administrator. - **GorkyCAD**: automatic diagram and BOM generation from floor plan, auto-selection of breakers and cross-sections, auto-placement of devices on DIN rails, AI assistant for standards checks. Everything works out of the box. **Verdict**: EPLAN is more flexible for complex customization, GorkyCAD goes faster from zero to result. ## 4. Platform and accessibility - **EPLAN**: Windows only. Requires powerful PC (16+ GB RAM, SSD, dedicated GPU). Network licensing via ePLAN License Manager. Annual updates, complex procedure. - **GorkyCAD**: web app. Works on Windows, macOS, Linux, Chromebook, tablet. No installation. Weekly updates, transparent to user. **Verdict**: GorkyCAD wins on accessibility. Open a project from any device, anywhere. ## 5. Learning curve - **EPLAN**: productive work requires 1-3 months of training. EPLAN Certified Engineer (ECE) certification is expensive and time-consuming. - **GorkyCAD**: "pick up and work" interface. Basic skills — 30 minutes. Full proficiency — 2-3 days. **Verdict**: GorkyCAD is dozens of times faster to learn. For hiring new staff, this is critical. ## When EPLAN is still needed We'll be honest: EPLAN is irreplaceable when: 1. You design industrial cabinets with hundreds of devices and complex 3D layouts 2. Enterprise-level multi-user work with version control is required 3. End-to-end ERP/PLM integration (SAP, Teamcenter) is needed 4. Client requires documentation specifically in EPLAN format (Z13, AML) 5. Project includes hydraulics, pneumatics, and instrumentation simultaneously In all other cases — especially residential, commercial, and small production sites — GorkyCAD gets the job done faster, cheaper, and more conveniently. ## Summary table | Criterion | EPLAN Electric P8 | GorkyCAD Pro | |---|---|---| | Price | €3,000-6,000/yr | ~€10/mo | | Platform | Windows only | Browser (all OS) | | Learning | 1-3 months | 1-3 days | | Floor plan | No | Yes | | Auto diagram | Via macros | Out of the box | | AI assistant | No | Yes | | 3D cabinet layout | Pro Panel | Basic | | Industrial projects | Yes | Limited | The choice is not what's better "in general", but what's better for your tasks.

Top 5 mistakes in apartment panel layout design

Wed, 30 Jul 2025 00:00:00 GMT

## Why panel layout matters The panel is the heart of an apartment's electrical installation. Layout mistakes mean: inconvenient maintenance, no expansion capability, overheating, and in the worst case — fire. Yet a correctly designed panel costs only 10-15% more than a flawed "budget" version. Let's examine the five most common mistakes we see in novice electricians' projects. ## Mistake 1: Panel with zero module reserve **Problem**: designer counts modules exactly for the current scheme. 12-module panel for a studio: main C32 (2), RCD (2), 4 MCBs (4), neutral + earth bars (2), terminals (2) = 12 — "everything fits". A year later, client installs AC — needs another C16. No space. Panel replacement: chasing, new panel, moving all devices. **Solution**: always allow **30-40% reserve** modules. Studio minimum: 18-20 modules; 2-3 bed apartment: 24-36 modules. Cost difference between 24-module and 12-module panel: ~$5-10 — savings that backfire. ## Mistake 2: One RCD for all groups **Problem**: a single 40A/30mA RCD for all socket circuits. It trips — all sockets go dead: fridge defrosts, computer loses unsaved work, aquarium light goes out. Per IEC 60364: splitting across multiple RCDs is recommended for tripping selectivity. Optimal: separate RCD for "wet" zones (kitchen, bathroom), separate for living rooms. **Solution**: minimum 2-3 RCDs per apartment panel. Grouping: RCD1 — kitchen (sockets + stove), RCD2 — bathroom + washer, RCD3 — living rooms. One trips — others keep working. ## Mistake 3: Neutral bar in wrong place **Problem**: neutral bar at panel bottom, RCD at top. N wires cross the entire panel, creating EMI and complicating maintenance. Worse: neutral wires from different RCDs mixed on a common bar — RCD will nuisance-trip because the current sum through it is non-zero. **Solution**: separate neutral bar (or section) per RCD, placed adjacent to its RCD. Group line neutrals connect to their RCD's bar. Pre-RCD and post-RCD neutral bars physically separated. ## Mistake 4: Panel in a niche without depth margin **Problem**: panel in an 80 mm deep niche. IP41 enclosure, 76 mm deep. "Almost fits." But internal wiring adds volume. Cover won't close without force. Wires get pressed — insulation wears against enclosure edge within a year. **Solution**: niche depth should exceed panel + wiring depth by 10-15 mm. Or use surface-mount panel (no niche needed). ## Mistake 5: No voltage monitoring relay **Problem**: neutral break in floor panel → phase imbalance → 380 V instead of 230 V enters apartment. All connected equipment burns out in seconds. Damage: $600-3,500+. Per modern standards: overvoltage protection required in residential (SPD Class II or voltage relay). **Solution**: voltage monitoring relay at input — disconnects load when voltage exceeds 170-270 V limits. Cost: from ~$20. Pays for itself on the first surge. Additionally: SPD Class II for lightning and switching surge protection — mandatory for overhead supply lines. ## How GorkyCAD prevents these 1. Warns at >85% panel module fill 2. Recommends multiple RCDs by room function 3. Auto-builds N-bar topology per RCD 4. Checks niche depth vs panel depth 5. Recommends voltage relay and SPD based on supply type

Apartment electrical design per PUE: complete walkthrough

Fri, 25 Jul 2025 00:00:00 GMT

## Initial data Let's walk through a real project: a 60 m² two-room apartment in a panel building. Client — a family of three. Full electrical supply design per PUE/IEC standards required. ## Step 1: Floor plan and electrical point placement In GorkyCAD, we load the floor plan (DWG/DXF or draw with built-in tools) and place: - **Kitchen (12 m²)**: 6 outlets (work zone — 4 doubles above counter + 1 fridge + 1 stove), 2 lights, 1 switch - **Living room (18 m²)**: 5 outlets (TV zone — 3, general — 2), chandelier + wall lamp, 2 switches (main + pass-through) - **Bedroom (14 m²)**: 4 outlets (both bedside + workstation + general), chandelier, 2 switches - **Bathroom (4 m²)**: 1 outlet for washing machine, light, switch (external) - **Hallway (8 m²)**: 2 outlets, light, switch - **Balcony (4 m²)**: 1 outlet, light Total: 19 outlets, 7 light points, 8 switches. ## Step 2: Grouping and load calculation Distribution into groups per IEC 60364: | Group | Rooms | Load | Icalc | |---|---|---|---| | Gr.1 — Lighting | All rooms | 0.8 kW | 3.5 A | | Gr.2 — Kitchen outlets | Kitchen | 3.5 kW | 15.2 A | | Gr.3 — Room outlets | Living, bedroom, hallway | 2.0 kW | 8.7 A | | Gr.4 — Washing machine | Bathroom | 2.2 kW | 9.6 A | | Gr.5 — Balcony | Balcony | 0.5 kW | 2.2 A | Total installed: 9.0 kW. Calculated (diversity factor 0.7): 6.3 kW. Input current: 28.7 A. ## Step 3: Breaker and RCD selection **Group breakers**: - Gr.1: C10, cable VVGng-LS 3×1.5 - Gr.2: C20, cable VVGng-LS 3×2.5 - Gr.3: C16, cable VVGng-LS 3×2.5 - Gr.4: C16, cable VVGng-LS 3×2.5 - Gr.5: C10, cable VVGng-LS 3×1.5 **RCDs**: - RCD1 (Gr.2 — kitchen): 25A, 30 mA, Type A - RCD2 (Gr.3-4 — rooms + washer): 25A, 30 mA, Type A - Gr.1 and Gr.5 without RCD (lighting — not required) **Main breaker**: C40, input cable 3×6 mm². ## Step 4: Panel layout Surface-mount panel, 24 modules. Fill order (top to bottom): 1. Main C40 — 2 modules 2. RCD1 25A/30mA Type A — 2 modules 3. Gr.2 (C20) + Gr.3 (C16) + Gr.4 (C16) — 3 modules 4. RCD2 25A/30mA Type A — 2 modules 5. Gr.1 (C10) + Gr.5 (C10) — 2 modules 6. Neutral bar + ground bar — 4 modules Total: 15 modules used. Reserve: 9 modules. ## Step 5: BOM GorkyCAD generates the BOM automatically — panel, MCBs, RCDs, cables, outlets, switches, lights — all counted from the model. ## Step 6: Cable schedule and export GorkyCAD generates a cable schedule with routing and lengths. Export: PDF (full album), Excel (BOM), JSON (for integration). **Result**: project ready in 25-30 minutes. All calculations, selectivity and voltage drop checks — automatic.

How to migrate from AutoCAD Electrical to GorkyCAD: a migration plan

Sun, 20 Jul 2025 00:00:00 GMT

## Why migrate AutoCAD Electrical is a powerful but expensive and complex tool. For residential and commercial building electrical design, 80% of its functionality is redundant, and project time is 5-10× longer than in a specialized tool like GorkyCAD. Migration shouldn't be painful. Here's a proven plan. ## Phase 1: Project audit (1-2 days) List all project types you do in AutoCAD Electrical: apartments/houses, offices, small commercial, industrial (if any). For each: time per project, repetitive operations %, manual work %. **Result**: understanding which projects can immediately move to GorkyCAD. ## Phase 2: Data export and preparation (2-3 days) **DWG/DXF drawings**: GorkyCAD reads them directly. Typical floor plans load as underlay. Import quality: layers, blocks, dimensions preserved. **Block libraries**: Map AutoCAD Electrical blocks (outlets, switches, lights) to GorkyCAD intelligent objects via the "Library Import Wizard" — one-time setup. **Panel schematics**: Single-line diagrams don't auto-transfer (different logic). But parameters (MCB ratings, cross-sections, lengths) can be exported via Data Extraction to Excel and imported to GorkyCAD. ## Phase 3: GorkyCAD template setup (1-2 days) Create project templates matching your AutoCAD templates: floor plan template, panel configuration template, BOM template, calculation methodology template. One-time investment, pays off on every subsequent project. ## Phase 4: Team training (2-3 days) - Day 1: interface, project creation, plan import, electrical point placement - Day 2: groups, calculations, panel, BOM, export - Day 3: real project under mentor guidance After 3 days, engineers work independently in GorkyCAD. ## Phase 5: Pilot project (3-5 days) Run a typical project (50-70 m² apartment) in GorkyCAD parallel to your normal process. Compare: time (25-35 min vs 3-5 hours), error count, output quality, engineer satisfaction. ## Phase 6: Full transition (1-2 weeks) After successful pilot: move all new residential/commercial projects to GorkyCAD. Keep AutoCAD Electrical for industrial only. Set up BOM export to ERP/CRM integration. Assign template/knowledge base owner. ## Economic effect Typical design bureau (3 engineers): - Time saved: 15-20 hrs/engineer/month - License savings: $7,500-15,000/year (3 seats) - Error/redo reduction: ~40% - Migration payback: 1-2 months

Automatic panel assembly: how it works in GorkyCAD

Fri, 18 Jul 2025 00:00:00 GMT

## What is auto panel assembly Auto panel assembly is a key GorkyCAD Pro feature. The engineer places electrical objects on the floor plan, assigns groups and subgroups — and GorkyCAD automatically composes the distribution panel: selects devices, places them on DIN rails, creates busbars, and outputs the BOM. This saves 1-3 hours of manual work per panel. ## Step 1: Building Feeder Topology Feeder Topology is a hierarchical power distribution model. GorkyCAD builds it automatically: 1. Identifies the power source (main incomer) 2. Analyzes consumer groups (lighting, outlets, heavy loads) 3. Builds hierarchy: Incomer → Main breaker → RCD → Group breakers → Consumers 4. Determines if additional levels are needed (sub-panels, floor panels) ## Step 2: Device selection For each group, GorkyCAD selects: - **MCB**: rating = Icalc × 1.25, curve (B/C/D) by load type, breaking capacity by Isc - **RCD**: rating ≥ MCB rating, leakage current (10/30/100/300 mA), type (A/AC) - **RCBO**: if group needs individual leakage protection ## Step 3: DIN rail placement The placement algorithm solves a 1D bin-packing problem: 1. Sorts devices by type: incomer → RCDs → group MCBs → terminals 2. Groups by phase (L1, L2, L3 — for 3-phase panels) 3. Places left to right, top to bottom (multi-row panels) 4. Respects thermal gaps (high-rated breakers — one module gap) 5. Reserves 15-20% modules for future expansion ## Step 4: Auto-busbars The busbar connects group MCBs to the RCD. Algorithm: 1. Determines which MCBs are fed by which RCD 2. Calculates busbar pole count (1P, 2P, 3P) 3. Selects busbar length (12, 24, 36, 56 modules) 4. Splits long busbars if MCBs exceed one busbar capacity ## Step 5: Thermal check GorkyCAD checks panel thermal conditions: - Total heat dissipation of breakers at rated load - Internal panel temperature (considering IP rating, enclosure material, ambient) - If temperature exceeds 40°C — warning and recommendation to enlarge enclosure ## Step 6: Documentation generation Final step — automatic generation: - **Panel schematic** — graphical DIN rail layout with positions - **BOM** — complete list with part numbers and quantities - **Label sheet** — position table for printing device labels - **Basic 3D view** — panel visualization for the client ## Result The engineer gets a fully designed panel in 30 seconds of automatic composition. Just review — and send to production.

SPD Guide: Surge Protection for Electrical Panels

Fri, 18 Jul 2025 00:00:00 GMT

## What is surge overvoltage Short-duration (µs-ms) voltage spike caused by: - **Lightning** (direct strike or induced) — up to hundreds of kV - **Switching** (motor/transformer disconnection) — 2-10 kV ## Three SPD classes ### Class I (Type 1 / Class B) For direct lightning strike (10/350 µs waveform). At the building incomer. Iimp ≥ 12.5 kA/pole, Up ≤ 2.5 kV. Spark gap technology. ### Class II (Type 2 / Class C) For residual and switching surges (8/20 µs). Floor/distribution panels. Imax ≥ 40 kA total, Up ≤ 1.5 kV. Varistor. ### Class III (Type 3 / Class D) Fine protection for end equipment. At the outlet. In ≥ 3 kA, Up ≤ 0.8 kV. Combined varistor + GDT. ## Cascade coordination Class I (main panel) → Class II (sub-panel) → Class III (outlet). Minimum 10 m cable distance between Class I and II. Otherwise — decoupling inductors needed. ## Selection parameters - Uc ≥ 275 V (L-N), Uc ≥ 350 V (L-PE) for 230/400 V network - Up: lower is better. Class II Up must be ≤ equipment withstand category - Network type matters: TN-C, TN-S, TN-C-S, TT — different connection schemes ## Do I need SPD in my apartment? - City apartment >5 floors: built-in appliance protection usually enough - Private house with overhead line: **Class I + II mandatory** - Private house with underground feed: Class II sufficient - Frequent thunderstorms (mountains, south): Class I + II mandatory Cost: Class I from $50, Class II from $25. Total home protection: $75-150. Compare to burnt appliances and rewiring.

How to read single-line diagrams: complete guide

Wed, 16 Jul 2025 00:00:00 GMT

What is a single-line diagram

A Single-Line Diagram (SLD) is a simplified graphical representation of an electrical network where all three phases are shown as a single line. It is the main document of any electrical supply project — from an apartment to a factory.

An SLD shows:

Power source (transformer, generator, utility feed)
Transmission lines and cable lines
Switching devices (breakers, disconnectors, contactors)
Protective devices (RCDs, fuses, relays)
Measuring instruments (meters, current transformers)
Busbars and distribution panels
Outgoing circuits with consumer labels

Once you learn to read an SLD, you can understand the electrical structure of any facility in 2–3 minutes.

Where single-line diagrams are used

Electrical design projects for residential, commercial, industrial buildings
Main switchboard (MSB) passport — on the inside of every apartment building panel door
Substation auxiliary panels
Grid connection agreements
Reconstruction and modernization projects

Symbols: main elements

Per IEC 60617 and IEEE 315 standards:

Switching devices

Circuit breaker (MCB/MCCB) — code QF. Drawn as a line break with a diagonal stroke (trip unit).
RCD / RCBO — code QFD. Added differential transformer symbol (oval or I∆).
Disconnector / Isolator — code QS. Line break without the diagonal stroke (no trip unit).
Contactor — code KM. Line break with a semicircle (electromagnetic coil).

Measuring devices

Current Transformer (CT) — code TA. Two intersecting circles on the line. E.g., CT 300/5: 300 A primary = 5 A secondary.
Voltage Transformer (VT) — code TV.
Energy meter — code PI. Rectangle with an arrow or Wh (watt-hours).
Ammeter, Voltmeter — codes PA, PV. Circle with letter A or V.

Other elements

Busbar — thickened horizontal or vertical line. May be labeled: BB1 (Section I), BB2 (Section II).
Cable line — thin line with marking: "XLPE 5×10 mm², L=45 m."
Power transformer — code T. Two intersecting circles on the line.
Surge arrester (SPD) — code FV. Triangle (varistor) on the line.

Step-by-step: analyzing a residential MSB diagram

Let's analyze a real Main Switchboard (MSB) diagram for a 9-story residential building.

Step 1: From utility feed to main breaker

Look at the top-left corner. Cable from the transformer station: marked "AL armour 4×150 mm², L=120 m" — aluminum armored cable, 4 cores × 150 mm².

Next: disconnector QS1 (400 A) — for visible isolation during maintenance. Then: main circuit breaker QF1 (C400, 400 A) with electronic trip unit.

Step 2: Metering section

After the main breaker: three CTs TA1-TA3 (400/5, class 0.5S). Signal wires go to energy meter PI1 — utility revenue metering.

Step 3: Busbar sectioning

Busbars split into two sections: BB1 (Section I) and BB2 (Section II). Bus-tie breaker QF3 (C250) between them — normally open (N.O.). On loss of one supply, the bus-tie closes.

Step 4: Outgoing circuits

Circuits branching down from the busbars:

QF4 (C63) → Staircase 1 panel: "FRLS 5×35 mm², L=18 m" (fire-resistant cable to the staircase panel)
QF5 (C25) → Elevator 1: "5×6 mm², L=55 m" with Type B RCD 30 mA
QF6 (C40) → Common area lighting panel: "5×10 mm², L=25 m"
QF7 (C16) → Emergency lighting panel: with ATS (Automatic Transfer Switch)

Step 5: Selectivity check

Chain: QF1 (C400) → QF4 (C63). During a fault in the staircase panel, QF4 (C63) trips first; QF1 (C400) stays on — selectivity achieved. Rating ratio 400/63 ≈ 6.3 — well above the 1.6 minimum.

Common reading mistakes

Confusing disconnector and breaker: a disconnector (QS) cannot interrupt fault current. If there's no breaker/fuse after a disconnector — that's a design error.
Ignoring cable type: "XLPE 3×2.5" and "FRLS 3×2.5" are different cables. Fire-resistant (FRLS) is mandatory for escape routes.
CT/breaker mismatch: a 150/5 CT before a 250 A breaker — the CT will be damaged on overload.
Missing RCDs: the diagram must clearly show which circuits are RCD-protected. Lighting — typically without RCD; outlets — with 30 mA RCD.

Standards reference

IEC 60617 — graphical symbols for diagrams
IEC 61082 — preparation of documents in electrotechnology
IEEE 315 — graphic symbols for electrical diagrams
IS 2032 — Indian standard for graphical symbols

How GorkyCAD simplifies reading and creating SLDs

In GorkyCAD, the single-line diagram is generated automatically from the project model. All elements are labeled: codes (QF, QS, TA, PI), ratings, cable types, lengths. Hover over any element for a tooltip with parameters. No guessing what a symbol means — the system explains everything.

Why you don't need AutoCAD Electrical for an apartment

Tue, 15 Jul 2025 00:00:00 GMT

## The Problem When an electrical engineer gets an apartment electrical design project, the first question is: what tool to use? Many habitually reach for AutoCAD Electrical or even EPLAN. This is a mistake. Heavy CAD systems were created for industrial facilities — factories, power plants, multi-story business centers with thousands of equipment units. For a 60 m² apartment, their functionality is 95% redundant. ## What's actually needed for an apartment An apartment electrical project requires: 1. **Floor plan** with outlets, switches, and lights placement 2. **Single-line calculation diagram** of the apartment panel 3. **Panel schematic** — device layout on DIN rails 4. **Specification (BOM)** — equipment list with quantities 5. **Calculations**: loads, cable cross-section, short-circuit currents 6. **Cable schedule** — types, lengths, installation methods And all of this — in a PDF for the client and electricians. ## Why AutoCAD Electrical is overkill - **Cost**: AutoCAD Electrical license — from $2,500/year - **Complexity**: just learning the interface takes 2-3 weeks - **No calculations**: AutoCAD doesn't calculate loads, cross-sections, short-circuit — it only draws - **No automation**: every line, every symbol must be drawn manually - **Windows only**: requires powerful hardware and Windows ## What GorkyCAD offers GorkyCAD is not a drafting tool — it's an engineering model: - **Single model**: floor plan, schematic, panel, BOM — all derived from one model - **Automation**: placed outlets → panel breakers auto-selected → schematic auto-built → BOM auto-generated - **Calculations**: loads, cross-sections, short-circuit, voltage drop — automatically - **Browser-based**: works on any computer, even Chromebooks - **Price**: from free plan to $12/mo for Pro ## Result Typical apartment electrical project in AutoCAD Electrical: **4-6 hours**. In GorkyCAD: **20-30 minutes**. That's 10-15x faster. Not because GorkyCAD "simplifies" — it automates routine, leaving decision-making to the engineer.

Free software for electricians in 2025

Mon, 14 Jul 2025 00:00:00 GMT

Why free software is serious business

Many electricians think: "Free = unprofessional." In 2025, that's no longer true. Free and open-source tools cover 80% of an electrical designer's tasks: schematics, calculations, floor plans, BOMs. You only pay with your time — and we'll help you pick the right tool.

1. QElectroTech — schematics and symbol libraries

QElectroTech (qelectrotech.org) is a free, open-source electrical schematic editor. Comparable to EPLAN and AutoCAD Electrical in basic functionality.

Pros:

Free, no restrictions
Cross-platform (Windows, Linux, macOS)
Own .qet format, export to DXF, PDF, PNG
Built-in symbol library (IEC, GOST)
Auto-numbering of conductors and terminals
Active community: symbol collections for Siemens, Schneider, ABB

Cons: no load/S/C calculations — drafting only. No 3D panel layout.

When to choose: circuit diagrams, panel wiring diagrams, automation schematics. Ideal for 10–50 sheet projects.

2. ProfiCAD — quick schematic drafting

ProfiCAD (proficad.com) is a freemium editor (free version with watermark on print). Very simple interface.

Pros: minimal learning — 15 minutes; ready libraries for MCBs, RCDs, relays, terminals, PLCs; auto-generated BOM.

Cons: no project hierarchy (pages), no macros. Awkward for large projects.

When to choose: simple residential panel, small distribution board, quotation schematic.

3. KOMPAS-Electric Express — free CAD from Russia

KOMPAS-Electric Express (kompas.ru) is a free version of a professional product from ASCON.

Pros: full GOST symbol library, circuit diagrams + BOM, PDF/DXF export.

Cons: Windows only, limited number of components in Express. Registration required.

When to choose: projects under Russian standards (ESKD/SPDS), when client requires KOMPAS format documentation.

4. GorkyCAD Free — cloud CAD for electricians

GorkyCAD (gorkycad.pro) is a web tool for electrical design. Free plan: one project with basic features.

Pros:

Floor plan + single-line diagram + panel + BOM — single model
Auto-calculation: loads, cable cross-sections, S/C currents, voltage drop
Browser-based (Windows, Mac, Linux, Chromebook)
Built-in online calculators at gorkycad.pro/tools/: S/C current, lighting, voltage drop, breaker selection
Export: PDF, Excel, JSON

Cons: internet needed (except PWA mode). No industrial-level multi-line schematics.

When to choose: apartment, house, or office electrical project. When you need engineering calculations, not just drafting.

5. Dialux evo — lighting design

Dialux evo (dialux.com) is a free professional lighting design tool. De-facto standard in lighting engineering.

Pros: illuminance calculation (lux), 3D visualization, luminaire databases from all manufacturers (Philips, Osram, LEDVANCE), reports per EN 12464-1.

Cons: Windows only, complex UI, requires training (2–5 days).

When to choose: office, warehouse, retail, or sports hall lighting design.

Comparison table

Software	Schematics	Calculations	Floor Plan	Platform	Difficulty
QElectroTech	★★★★★	—	—	Win/Mac/Linux	Medium
ProfiCAD	★★★★	—	—	Windows	Low
KOMPAS-El. Express	★★★★	—	—	Windows	Medium
GorkyCAD Free	★★★★	★★★★★	★★★★	Browser	Low
Dialux evo	—	★★★★★	★★★	Windows	High

Which software to choose: recommendations

Apartment / house: GorkyCAD Free — plan + calculation + schematic + BOM in one window, 20 minutes per project.
Office / retail: GorkyCAD (electrical) + Dialux evo (lighting).
Industrial panel: QElectroTech (circuit diagrams) + GorkyCAD (calculations & BOM).
Strict GOST compliance: KOMPAS-Electric Express or commercial version.
Quick schematics only: ProfiCAD.

Relay protection basics: overcurrent protection explained

Sat, 12 Jul 2025 00:00:00 GMT

What is relay protection (RPA)

Relay Protection and Automation (RPA) is a set of devices that detect faults in the electrical network (short circuits, overloads, earth faults) and disconnect the damaged section, preventing the accident from spreading.

Without RPA, any short circuit would cause a substation fire, transformer failure, and a district-wide blackout for weeks. Relay protection operates in 0.02–0.5 seconds and saves equipment worth millions.

Main types of relay protection

OCP — Overcurrent Protection (МТЗ): trips when line current exceeds a set threshold for a set time. Protects against overloads and distant faults.
IOC — Instantaneous Overcurrent (ТО): trips instantly at very high current — typically for faults close to the source.
Gas protection (Buchholz relay): for oil-filled transformers. Reacts to gas released from oil during internal faults.
Differential protection: compares current at the input and output of the protected element. If the difference exceeds the setting — internal fault. Used for transformers, generators, busbars.
Earth fault protection: responds to zero-sequence current. Critical for isolated-neutral networks (6–35 kV in Russia and India).

Calculation example: OCP & IOC for a 10 kV cable line

Given:

10 kV cable line, 2.5 km, cable 3×120 mm² Al
Maximum operating current: Iop.max = 180 A
3-phase S/C current at line end: Isc.min = 3200 A
S/C current at line start: Isc.max = 8500 A
CT: 300/5 (ratio Kct = 60)

Step 1: OCP pickup current

Formula: Ipu = (Krel × Kss × Iop.max) / Krt

Where:

Krel = 1.2 — reliability coefficient
Kss = 1.3 — self-start coefficient (for industrial load)
Krt = 0.85 — relay return coefficient

Ipu = (1.2 × 1.3 × 180) / 0.85 = 330 A

Step 2: OCP sensitivity check

Sensitivity: Ks = Isc.min / Ipu = 3200 / 330 ≈ 9.7

Required Ks ≥ 1.5 for the main zone. 9.7 — excellent, protection reliably detects faults at line end.

Step 3: IOC pickup current

IOC is set above maximum fault current at line end: Ipu.ioc = Krel × Isc.end.max

Krel = 1.3: Ipu.ioc = 1.3 × 3200 ≈ 4160 A

Step 4: IOC sensitivity check

Ks.ioc = Isc.max / Ipu.ioc = 8500 / 4160 ≈ 2.04

Required Ks ≥ 1.2 for IOC. 2.04 > 1.2 — passes.

Step 5: Secondary-side settings

OCP: Isec = 330 / 60 = 5.5 A

IOC: Isec.ioc = 4160 / 60 = 69.3 A

Standards reference

IEC 60255 — measuring relays and protection equipment
IEEE C37.112 — inverse-time characteristic curves
IS 3842 — Indian standard for relay protection

Common mistakes

Underestimated Ks — the most dangerous mistake. If Ks < 1.3, protection may fail during a real fault.
Wrong Kss — for purely cable lines without motors, Kss = 1.0, not 1.3.
CT connection scheme — star vs delta connection changes secondary current by √3.
Ignoring fault arc resistance, especially for 0.4 kV lines.

How GorkyCAD helps

GorkyCAD calculates S/C currents automatically and suggests recommended OCP/IOC settings. The engineer reviews and approves — eliminating arithmetic error risk from manual calculation.

IEC 60364 vs PUE vs IS 732: comparing electrical standards

Sat, 12 Jul 2025 00:00:00 GMT

## Introduction An electrical designer working in Russia and India or with international projects encounters three standards systems: - **PUE** (Electrical Installation Code, 7th ed.) — Russia and CIS countries - **IEC 60364** — international standard, basis for European norms - **IS 732** (Indian Standard, adopted from IEC 60364) — India Although IS 732 is based on IEC 60364, significant differences exist in practice. GorkyCAD supports calculations per all three systems — with automatic switching. ## Comparison table | Parameter | PUE (Russia) | IEC 60364 | IS 732 (India) | |---|---|---|---| | **Nominal voltage** | 230/400 V ±10% | 230/400 V ±10% | 230/400 V (50 Hz) | | **Voltage drop limit** | 5% from MDB | 3% (lighting), 5% (other) | 3% (lighting), 5% (other) | | **Cable sizing basis** | PUE tables 1.3.4-1.3.6 | IEC 60364-5-52 | IS 732, table 5 | | **Iz 2.5 mm² Cu** | 27 A (3-core, in chase) | 27 A (method C) | 27 A (method C) | | **Overcurrent protection** | Ch. 3.1 | IEC 60364-4-43 | IS 732 Section 4 | | **RCD mandatory** | Cl. 7.1.71 (bathroom, sockets) | IEC 60364-4-41 | IS 732 (≤20A sockets, wet areas) | | **Earthing** | TN-C-S, TN-S | TN, TT, IT | TN-S (preferred) | | **Selectivity** | Recommended | IEC 60364-5-53 | IS 732 Section 5 | | **Lightning protection** | Separate standard | IEC 62305 | IS/IEC 62305 (adopted) | | **S/C current calc** | GOST 28249 | IEC 60909 | IS 13234 (based on IEC 60909) | ## Key calculation differences ### Cable current ratings For 2.5 mm² copper, 3-core: - PUE (in chase, brick): 27 A - IEC 60364 (method C): 27 A - IS 732 (method C): 27 A → Minimal differences here. ### Voltage drop - PUE: single 5% limit for everything - IEC/IS: split — 3% lighting, 5% other A lighting circuit at 4.5% passes PUE but fails IEC/IS (needs 3%). ### RCD protection - PUE: mandatory for socket circuits, bathrooms. Type A recommended since 2020. - IS 732: mandatory for all ≤20A sockets in residential + all wet-area sockets. Type A recommended. - IEC 60364 (Germany): RCD ≤30 mA mandatory for all socket circuits ≤32 A. → IS 732 is generally stricter than PUE in coverage. ### Earthing system - Russia: TN-C-S dominant (combined PEN at input, split at MDB). PUE permits. - India: de-facto standard — TN-S with separate N and PE throughout. IS 732 recommends TN-S for new installs. - IEC: recognizes all systems, TN-C-S has usage restrictions. → For Indian projects: PEN conductor not allowed after separation point. Always run separate N and PE. ## Terminology differences | Russian (PUE) | English (IEC) | हिन्दी (IS 732) | |---|---|---| | Автоматический выключатель | Circuit Breaker (MCB) | परिपथ विच्छेदक (MCB) | | УЗО | RCD | अवशिष्ट धारा युक्ति (RCD) | | ГРЩ | Main Distribution Board (MDB) | मुख्य वितरण बोर्ड (MDB) | | Сечение | Cross-Sectional Area (CSA) | अनुप्रस्थ काट क्षेत्र (CSA) | ## How GorkyCAD simplifies work 1. Country/standard selection at project creation — all norms auto-configured 2. Standard switching for existing projects (e.g., started per PUE, client requested IS 732) 3. Automatic recalculation on standard change 4. Difference highlighting (where norms diverge) 5. Trilingual BOMs (Russian/English/Hindi) For engineers working on export or with Indian clients, this saves hours of manual recalculation and cross-checking.

Power Supply Categories: Class 1, 2, 3 — What Every Designer Must Know

Sat, 12 Jul 2025 00:00:00 GMT

## Three reliability categories per PUE/IEC PUE Chapter 1.2 defines 3 power supply reliability categories. The choice is not at the designer's discretion — it's mandated by regulations and technological necessity. ### Category I (critical) **Requirements:** two independent mutually-reserved sources + third independent (for special group). ATS with transfer time ≤ 0.5 sec. Diesel generator often added. **Consumers:** operating rooms, ICUs, fire pumps, smoke exhaust, data centers Tier III+, continuous-cycle industrial equipment. **Cost:** highest. Two inputs + generator + ATS increase panel cost 4-6× vs Category III. ### Category II **Requirements:** two independent sources. Switching can be manual or automatic (ATS not mandatory). Interruption during switching — up to 1 hour for manual. **Consumers:** residential buildings >5 floors, schools, shopping centers >2000 m², offices >50 people, non-continuous production lines. **Implementation:** two inputs with ATS or manual transfer switch. ### Category III **Requirements:** one source. Interruption for repair — up to 24 hours. **Consumers:** private houses, apartments in low-rise buildings, small shops, garages, temporary structures. ## Common mistake: over-specifying category Doubles panel cost, adds unnecessary cable — more elements = more potential failures. ## Common mistake: under-specifying category Project rejection, regulatory orders, risk of full outage on single-input failure. ## Practical approach: 10-floor residential building - Fire pumps: Category I - Elevators (<17 floors): Category II - Emergency lighting: Category I - Apartments: Category II Design: two inputs to main panel. Fire pumps and emergency lighting with ATS. Rest — sectioned across two inputs with tie breaker.

PLC programming for electricians: where to start

Thu, 10 Jul 2025 00:00:00 GMT

What is a PLC and why does an electrician need it

A PLC (Programmable Logic Controller) is an industrial computer that controls equipment: conveyors, pumps, ventilation, lighting, machine tools. Where control logic was once built with relays and contactors, it's now all moved into a PLC program.

For an electrician, knowing PLC programming is a ticket to the world of automation. Demand for automation engineers is growing in Russia, India, and globally. An automation engineer's salary is typically 1.5–2× that of an installation electrician.

The 5 IEC 61131-3 languages

The international standard IEC 61131-3 defines 5 PLC programming languages. An electrician will find it easiest to start with those that resemble electrical diagrams:

LD (Ladder Diagram) — looks like an electrical schematic: contacts, relay coils, timers. Ideal for electricians — you already know how to read such diagrams.
FBD (Function Block Diagram) — functional blocks. Connect blocks (AND, OR, timers, counters) with lines — just like an automation functional diagram.
ST (Structured Text) — similar to Python or Pascal. Great for complex math, loops, data processing. Most flexible, but requires programming skills.
SFC (Sequential Function Chart) — describes process stages: step 1 → condition → step 2. Useful for cyclic processes.
IL (Instruction List) — assembler-like. Being phased out, but still found in legacy Siemens S7-300 projects.

Recommendation: start with LD and FBD — as an electrician you already understand their logic. Then learn ST for complex tasks.

Where to start: hardware and software

Most accessible learning ecosystem:

Siemens LOGO! — a mini-PLC with LOGO! Soft Comfort software (free). Perfect for first steps: lighting, gates, pumps.
Siemens S7-1200 + TIA Portal — the industry standard. TIA Portal Basic is free.
Allen-Bradley Micro800 + CCW — for the US/India market. Connected Components Workbench is free.
CODESYS — free IDE, supports all 5 IEC 61131-3 languages. Download from codesys.com. The built-in PLC simulator lets you debug without any physical controller.
OWEN PLC110/PLC160 — Russian budget controllers (≈$80), programmed in CODESYS. Popular in Russia and CIS.
Segnetics (SMH4, Pixel) — Russian controllers with SMLogix IDE (FBD). Excellent for HVAC.

How GorkyCAD helps the automation engineer

When designing automation panels, GorkyCAD exports a BOM linked to PLC modules: digital inputs/outputs (DI/DO), analog inputs/outputs (AI/AO). This gives you a ready-made tag map for the PLC program. Instead of manually compiling a tag table, you get a structured list — and write the program faster.

3-month learning plan

Month 1: install CODESYS, complete built-in LD and FBD tutorials. Build a "motor start-stop" and "motion-sensor lighting control" program.
Month 2: buy a Siemens LOGO! or OWEN PLC110, set up a test bench with buttons and lights. Program and debug on real hardware.
Month 3: learn HMI panels (Weintek, Siemens KTP), build a simple operator screen. Learn Modbus RTU/TCP — polling sensors and actuators.

After 3 months, you'll have a portfolio of 3–5 mini-projects and can apply for a junior automation engineer position.

How to calculate cable cross-section: step-by-step guide

Thu, 10 Jul 2025 00:00:00 GMT

## Why correct cross-section matters Cable cross-section is a critical parameter. Too small — cable overheats, insulation melts, fire risk. Too large — wasted money on copper, difficult installation. The engineer must find the exact value. Calculation follows two criteria. The **larger** of the two is selected. ## Criterion 1: Heating (continuous current rating) Cables heat up when current flows. IEC 60364 / IS 732 specify maximum currents for each cross-section. ### Example Given: Icalc = 25 A, copper cable, 3 cores, in conduit. Per IEC table: copper 2.5 mm² → 27 A (sufficient). **Check**: Icalc (25 A) ≤ Imax (27 A) → 2.5 mm² passes heating criterion. ## Criterion 2: Voltage drop Per IEC, voltage drop from main panel to end consumer — max 5%. Formula: ΔU% = (2 × L × Icalc × cos φ) / (γ × S × Unom) × 100% Where: - L — cable length (m) - Icalc — calculated current (A) - γ — conductivity (copper ≈ 57 m/(Ω·mm²)) - S — cross-section (mm²) - Unom — nominal voltage (230 V single-phase) ### Example L = 30 m, Icalc = 25 A, cos φ = 0.92, copper. At S = 2.5 mm²: ΔU% = 4.2% < 5% → passes. At S = 1.5 mm²: ΔU% = 7.0% > 5% → fails. **Result**: choose 2.5 mm² (passes both criteria). ## GorkyCAD Algorithm GorkyCAD performs this calculation automatically for every circuit segment: 1. Determines Icalc from group total load 2. Selects cross-section by heating (IEC/IS 732/GOST tables) 3. Calculates voltage drop along entire circuit 4. Picks the larger of the two cross-sections 5. Rounds to nearest standard: 1.5, 2.5, 4, 6, 10, 16, 25 mm²... You just need to review and approve.

Single-line diagram in 5 minutes

Sat, 05 Jul 2025 00:00:00 GMT

## What is a single-line diagram The single-line calculation diagram is the main document of an electrical supply project. It shows: power source, panels, outgoing circuits with breaker ratings, cable cross-sections, and loads. All three phases are shown as one line — hence the name. In traditional design, the diagram is drawn manually — taking 30-60% of project time. ## How GorkyCAD builds it automatically 1. Place electrical objects on the floor plan 2. Assign groups (which outlets from which breaker) 3. GorkyCAD builds the panel hierarchy (Feeder Topology) 4. Loads, cross-sections, short-circuit currents are calculated 5. Diagram auto-generated — all connections, ratings, cross-sections ## What's on the diagram - Main breaker with rating - RCD with leakage current - Group breakers with ratings - Outgoing circuits with cable type and cross-section - Calculated loads per group - Total power ## Editing The diagram can be adjusted: rename groups, reorder breakers. When the plan changes, the diagram updates automatically — no redrawing needed. ## Result Single-line diagram — in 5 minutes instead of 2-4 hours. With automatic recalculation on any changes.

Cable Routing: 12 Rules That Will Save Your Project

Sat, 05 Jul 2025 00:00:00 GMT

## Why proper cable routing matters Cable installation is the most labor-intensive electrical work phase. It affects not just system operability but safety, maintainability, and cost of future upgrades. ### Rule 1: Minimum bend radii - Copper ≤10 mm²: R ≥ 6D - Copper >10 mm²: R ≥ 10D - Aluminum: R ≥ 15D ### Rule 2: No concealed wiring without as-built drawing Any chased or conduit route must be on the plan. ### Rule 3: Load-bearing wall chasing Max 25 mm depth, 3 m length horizontal. Max 50 mm vertical. Better to route through partitions. ### Rule 4: 30% conduit reserve Fill factor max 0.4-0.5. Always leave 30% free for future. ### Rule 5: Cable labeling Each cable labeled at both ends: group number, purpose, cross-section. ### Rule 6: Segregation Power and data cables — separate trays or metallic divider. 200 mm gap for unshielded, 50 mm for FTP/STP. ### Rule 7: Distance from heating pipes Min 200 mm from hot pipes (>60°C), 100 mm from cold pipes. ### Rule 8: Fire-resistant cables for escape routes FP cables must maintain function for 180 min (BS 5839, VDE 0108). ### Rule 9: Outlet heights Residential: 300 mm AFF. Kitchen (work zone): 100-150 mm above counter. Switches: 900 mm AFF. ### Rule 10: Pre-screed check Test all cables for continuity and IR (>0.5 MΩ). Photo-document routes with a tape measure. ### Rule 11: Outdoor temperature rating Cable must withstand -40°C to +40°C. Arctic-grade insulation needed. ### Rule 12: Expansion loops Every 30 m in rigid-mounted tray or direct burial runs.

Electrical safety calculations: S/C current, phase-neutral loop

Tue, 01 Jul 2025 00:00:00 GMT

Why calculate the phase-neutral loop

The single-phase S/C current (phase-neutral loop) determines whether the MCB will trip within the required time (0.4 s for 220 V, IEC 60364). Insufficient S/C current → MCB won't trip in time → the enclosure stays live.

Formula

Isc(1) = Uph / (Ztr + Zw × L). Where: Uph = 220 V, Ztr — transformer impedance (typically 0.01-0.05 Ω), Zw — loop impedance per km for the cable (phase + neutral), L — line length.

Example

Outlet 30 m from panel, cable 3×2.5 mm² (copper). Zw = 14.8 Ω/km. Zline = 14.8 × 0.03 = 0.444 Ω. Zloop = 0.02 + 0.444 = 0.464 Ω. Isc(1) = 220 / 0.464 = 474 A. C16 MCB: 16 × 10 = 160 A (C upper limit). 474 > 160 — protection works.

Automation in GorkyCAD

GorkyCAD automatically calculates S/C currents for each line, checks compliance with MCB characteristics, and warns on non-compliance. Saves up to 50 manual calculations per project.

What is protection selectivity and why you need it

Sat, 28 Jun 2025 00:00:00 GMT

## What is selectivity Protection selectivity is the system's ability to disconnect only the damaged section, leaving everything else energized. **Example without selectivity**: short circuit in an outlet → main breaker trips → entire house without power. **Example with selectivity**: S/C in an outlet → only that line's group breaker trips → other groups keep working. ## Types of selectivity 1. **Current-based** — upstream breaker has higher rating 2. **Time-based** — upstream breaker trips with a delay 3. **Energy-based** — modern breakers with energy selectivity ## How GorkyCAD checks it GorkyCAD automatically checks selectivity in the panel hierarchy: 1. Builds protection chain from final breaker to main 2. Compares ratings and characteristics (B/C/D) 3. On violation — warning and recommendation ## Practical example Apartment panel: main C40 → RCD 40A/30mA → group breakers C16. S/C in outlet (Isc ≈ 200 A): C16 trips in 0.01 s, C40 doesn't react in time. Selectivity achieved. S/C at input (Isc ≈ 1500 A): both trip. Need to reconsider — e.g., main breaker with D characteristic.

Grounding Types Explained: TN-C, TN-S, TN-C-S, TT, IT

Sat, 28 Jun 2025 00:00:00 GMT

## What is an earthing system The earthing arrangement determines how the source neutral and exposed conductive parts are connected to earth. Safety, protection device operation, and EMC all depend on this choice. IEC 60364 defines 5 types. In India — IS 3043. ## Letter meanings **First letter** — source neutral to earth: - T — earthed (solidly grounded neutral) - I — isolated **Second letter** — exposed parts to earth: - T — independently earthed - N — connected to source neutral **For TN only:** - C — Combined PEN conductor - S — Separate N and PE ## TN-C (old system) Common PEN conductor. Cheaper but dangerous — PEN break puts phase voltage on exposed metal. Banned in new buildings. ## TN-S (modern standard) 5-wire system (L1, L2, L3, N, PE). Maximum safety. Standard in Europe, recommended for hospitals, data centers. ## TN-C-S (compromise) TN-C before building entry, TN-S after PEN split at main panel. Split PEN into PE and N at the incoming device. Requires re-earthing of PE (≤10 Ω for 400/230 V). PEN minimum 10 mm² copper. Used in 90% of Russian residential buildings. Common in India for multistory apartments. ## TT (for private houses) Independent earth electrode for exposed parts. Mandatory RCD on incomer (IΔn ≤ 300 mA). Used when utility earth is unreliable. ## IT (hospitals, mines) Isolated neutral or high-impedance earthed. First fault — alarm only, no trip. Used in operating rooms, ICUs — where power continuity is critical. ## Selection guide | Building | System | |---|---| | Apartment | TN-C-S | | Private house | TT | | Office | TN-C-S | | Hospital | TN-S / IT | | Factory | TN-S | | Data center | TN-S |

Cable tray types and fill calculation

Sun, 22 Jun 2025 00:00:00 GMT

Cable tray types

Per IEC 61537: ladder (power cables, maximum load capacity), perforated (universal), wire mesh (light, for low-current networks), solid (for fire-hazard zones).

Fill factor

Total cable cross-section must not exceed 40% of tray cross-section for power circuits and 50% for control. Formula: Scable = Σ(π × d² / 4) × 1.1 (safety factor for uneven laying).

Calculation example

Given: 12 cables 5×2.5 mm² (d=10.2 mm), 5 cables 5×6 mm² (d=13.5 mm). Total area: S = 12 × 81.7 + 5 × 143.1 = 1696 mm². With 1.1 factor: 1865 mm². At 40% fill: Stray ≥ 1865 / 0.4 = 4663 mm² → select 200×50 tray (usable area ≈ 6000 mm²).

How AI helps the electrician (without replacing them)

Fri, 20 Jun 2025 00:00:00 GMT

## Philosophy GorkyCAD doesn't replace the engineer. AI is a tool that takes on routine and gives superpowers. The engineer makes decisions. AI checks, calculates, searches, explains. ## What AI does 1. **Checks standards**: is cable cross-section adequate, are breakers correctly selected, is selectivity maintained 2. **Explains calculations**: why this cross-section was chosen, how S/C current was calculated 3. **Searches objects**: "find all ungrounded outlets in the bedroom" — semantic search 4. **Gives recommendations**: "use Type A RCD for this group due to washing machine" ## What AI does NOT do - Does not make engineering decisions for you - Does not sign the project - Does not replace expert review - Does not require internet — works locally ## Result An engineer with AI assistant works 3-5x faster, makes fewer errors, gets explanations for every calculation. Not replacement — amplification.

Power Factor Correction: When You Need It and How to Calculate

Fri, 20 Jun 2025 00:00:00 GMT

## What is reactive power and cos φ In AC circuits, power has three components: active P (kW), reactive Q (kVAR), and apparent S (kVA). Power factor cos φ = P / S. **Typical cos φ values:** - Incandescent lamps, heaters: cos φ ≈ 1.0 - LED lights: cos φ ≈ 0.92-0.98 - Induction motors: cos φ ≈ 0.7-0.85 - Welding machines: cos φ ≈ 0.5-0.7 - UPS systems: cos φ ≈ 0.8-0.9 ## Why low cos φ is bad 1. **Utility penalties** — up to 30% of active energy cost 2. **Cable overheating** — current increases as 1/cos φ 3. **Oversized cables** required 4. **Voltage drop** increases 5. **Transformer underutilization** ## Calculation example: 100 kW office Measured cos φ = 0.75, target cos φ = 0.95. Qc = P × (tan φ1 — tan φ2) Qc = 100 × (0.882 — 0.329) = **55.3 kVAR** Select automatic capacitor bank 60 kVAR. ## Compensator types 1. Automatic capacitor banks (3-8 RUB/VAR) 2. Active harmonic filters (15-30 RUB/VAR) 3. Synchronous compensators (>5 MVAR) ## Payback Penalties: ~$150/month. Cable losses: ~$30/month. CAPEX 60 kVAR bank: ~$2,500. Payback: ~14 months.

Fire alarm electrical supply design

Sun, 15 Jun 2025 00:00:00 GMT

Regulatory framework

Fire alarm system power supply is governed by SP 5.13130, SP 6.13130, and IEC 60364. Fire alarm loads belong to Category I (critical) reliability.

Reliability category

Category I requires two independent power sources with ATS. Main supply + battery backup. Transfer time — max 3 seconds.

Cable lines

Fire alarm cables must be fire-resistant (FR) and flame-retardant. Marking: FRLS, FRHF. Routing in separate conduits. 180-minute survivability (E180) for evacuation routes.

Battery sizing

Battery capacity: C = (Istandby × 24 + Ialarm × 3) × 1.25. Where Istandby — standby current, Ialarm — alarm current (all sounders active), 24 and 3 — hours per standard.

Electricity metering automation in design

Sun, 08 Jun 2025 00:00:00 GMT

Why automate metering

Automated Meter Reading (AMR) systems are mandatory for new residential buildings and industrial facilities. Pulse-output meters are the most accessible integration method.

Connection diagram

A pulse-output meter connects to a data concentrator (DCU). The pulse output is a dry contact or optocoupler closing N times per kWh. Standard values: 100, 500, 1000, 5000 imp/kWh.

CT selection

For loads above 100 A, current transformers (CTs) are used. Accuracy class for revenue metering: 0.5S or 0.2S. Secondary rating: 5 A (standard) or 1 A (for long runs).

GorkyCAD and AMR

GorkyCAD automatically adds meters and CTs to the single-line diagram when the "Revenue Metering" option is enabled. The BOM includes all metering node equipment.

Circuit breaker selection: complete guide

Sun, 01 Jun 2025 00:00:00 GMT

The circuit breaker — foundation of protection

The circuit breaker (MCB) is the basic element of any electrical installation. Safety of people and equipment depends on correct selection.

Step 1: Rated current

MCB rating In is selected by design current: In ≥ Icalc. For a kitchen outlet group (3.5 kW): Icalc = 3500 / 230 = 15.2 A → select C16.

Step 2: Trip curve (B, C, D)

B — 3-5 In (lighting, general outlets), C — 5-10 In (universal, outlets, small motors), D — 10-20 In (large motors, transformers, welders).

Step 3: Breaking capacity

Icu must exceed the maximum short-circuit current at the installation point. For apartment panels: 4.5-6 kA. For main switchboards: 10-15 kA.

Step 4: Selectivity

The upstream breaker must be rated at least 1.6× the downstream one for current selectivity.