Engineering Toolkit
Select a category to access tools
Electrical Design & Sizing
Cable sizing, maximum demand, voltage drop, and circuit design suites.
10 ToolsRenewables, EV & HVAC
Solar PV, Battery Storage (BESS), EV Chargers, and Heat Pump calculators.
7 ToolsInspection & Testing (EICR)
Observation builders, safe isolation permits, PFC, and Zs calculators.
8 ToolsLighting & Commercial
LED ROI estimators, BS 5266 Emergency lighting planners, and Lux guides.
5 ToolsApprentice Training
18th Edition mock exams, AM2 simulators, and interactive flashcards.
6 ToolsGeneral Reference & Theory
Ohms law, kW/kVA converters, IP codes, and power factor calculators.
7 ToolsPublic Safety & Landlord
PRS compliance trackers, hazard diagnostics, and client EICR guides.
5 ToolsAbout the TMUK Engineering Tool Kit
As a professional electrical contractor, ensuring strict compliance with BS 7671:2018+A3:2024 is paramount. This bespoke suite of free engineering calculators has been developed by TMUK Group Ltd to assist electricians, designers, landlords, and duty holders in verifying their installations, sizing cables accurately, and generating statutory health and safety documentation.
Our Core Engineering Suites
- Electrical Design & Sizing: Advanced tools for accurate cable sizing, voltage drop verification, and complex maximum demand calculations for domestic, commercial, and industrial sites.
- Renewables, EV & HVAC: Dedicated Solar PV, Battery Storage, EV Charging, and Heat Pump planners.
- Inspection, Testing & EICR: Essential resources for verifying Earth Fault Loop Impedance (Zs), Prospective Fault Current (PFC), Ring Final Continuity testing, EICR Defect Classification, and digital Permit to Work (PTW) generation.
- Lighting & Commercial Estimating: Commercial calculators tailored for generating immediate LED return on investment (ROI) proposals, BS 5266-1 emergency lighting layouts, and rapid project quoting.
- Apprentice Training & Learning: Interactive test and exam engines designed to prepare electrotechnical learners for the City & Guilds 2382 exam, C&G 2391 assessment structures, and the rigorous AM2 practical verification bay.
- General Reference & Theory: Quick calculators for Ohm's Law, Star-Delta conversion, IP codes, and kVA conversions.
- Public Safety & Landlord Compliance: Guided diagnostic trackers to ensure properties meet the statutory requirements of the Private Rented Sector (PRS) regulations and basic consumer unit safety standards.
How to Use the Dashboard
Simply select the required engineering module from the grids above to launch the application. Each tool is designed to function flawlessly on mobile devices, allowing our field engineers, qualified supervisors, and apprentice learners to perform complex mathematical verifications or access study resources directly on-site without relying on signal-dependent cloud software.
Category Title
All-in-One Circuit Designer
Complete BS 7671 design engine. Calculate cable sizes, voltage drop, and diversity.
Cable Sizing Suite
Automatically size standard multicore cables based on Ib, Voltage Drop, and Install Methods.
Heavy Industrial Mains
Specify parallel single-core conductors (AWA/XLPE) with trefoil formation voltage drop logic.
Maximum Demand Calculator
Calculate connected load vs. maximum demand and apply BS 7671 diversity factors.
Voltage Drop Calculator
Verify BS 7671 statutory limits across single and three-phase circuits.
Containment Fill Calculator
Verify Conduit (40%) and Trunking (45%) sizing limits to BS 7671.
Adiabatic Equation Sizer
Calculate minimum CPC sizes using the BS 7671 adiabatic equation S = √(I²t)/k.
Main Earthing & Bonding
Size Main Earthing Conductors and Equipotential Bonding for all earthing systems.
SWA Gland & Cleat Selector
Instantly specify the correct BW/CW/CX gland pack and cleat diameter for SWA.
Circuit Protection Selector
Calculate Ib and automatically select correct MCB, RCBO, or Fuse ratings.
Solar PV & Battery Suite
Map roof space to kWp capacity, calculate clipping ratios, and specify storage.
Solar PV AC & DC Design
BS 7671 Section 712 Compliance, String Configuration & Protection calculator.
Battery Storage (BESS)
Capacity, EPS Runtime & Financial Payback Modeller.
EV Charging O-PEN Planner
Evaluate Section 722 earthing arrangements and open-PEN detection protocols.
EV Load Assessment
BS 7671 Section 722 Compliance & Supply Adequacy checker.
Heat Pump Sizer
Air-Source & Ground-Source Circuit Specification for Heat Pumps.
Heating Load Profiler
Underfloor, Trace & Space Heating Specification calculator.
RCD Risk Assessment
Dynamic EICR Coding Engine based on Installation Type and ESF BPG4 Issue 7.
EICR Observation Builder
EICR Field Observation Builder with Category, Defect, Location & C-CODE.
Digital Permit to Work
Safe System of Work (SSoW) field tool to digitally issue isolations & sanctions.
Maximum Zs Values
Find statutory 100% and temperature-adjusted 80% Earth Fault Loop Impedance limits.
Maximum Ze Evaluator
Evaluate external Ze parameters against standard limits for TN-S, TN-C-S, and TT.
Fault Current (PFC)
Calculate Prospective Fault Current (PSCC & PEFC) for switchgear ratings.
Ring Continuity (R1+R2)
Verify dead test readings or reverse-engineer continuity figures from live measurements.
EICR Testing Sequence
Comprehensive BS 7671 verification procedure detailing exact dead and live testing methodologies.
BS 5266 Emergency Lighting
2D layout simulator and coverage radii calculations for emergency escape routes.
Lighting Layout Estimator
Interactive 2D simulator using the Lumen Method for standard office layouts.
Commercial LED Payback Calculator
Calculate commercial lighting ROI, financial savings, and CO2 footprint reduction.
LED ROI Calculator
LED Energy Savings & ROI Commercial Lighting Upgrade Calculator.
CIBSE Lux Level Standard Guide
SLL Code for Lighting Compliance Standards checker.
Contracting Estimator
Rapid quotation engine. Calculate travel, plant hire, and bulk import materials.
Defect Classification Lab
Practise assigning C1, C2, C3, and FI classifications to real-world electrical faults.
AM2 Readiness Simulator
Practise zero-tolerance Safe Isolation procedures and visual fault diagnosis to NET standards.
Apprentice Training Hub
Knowledge base for C&G 2391 and AM2 prep. Review test sequences and reference data.
Microlearning & Flashcards
Master cable colours, regulations, and observation codes via spaced repetition.
18th Edition Mock Exam
Full 60-question dynamic exam engine mimicking real C&G 2382 assessments.
Cable Derating Thermal Sandbox
Mathematical visualisation tool. Manipulate ambient heat, insulation, and grouping sliders.
kW / kVA / Amps Multi-Converter
Rapid Single & Three-Phase Power Calculations.
kVA to Amps & Generator Sizing
Site Power, Temporary Supplies & Load Conversion.
EICR Frequency Guide
Determine the statutory testing periods and maximum intervals for electrical installations.
Star-Delta Converter
Instantly convert between Star and Delta three-phase motor or heater bank impedances.
Power Factor Correction
Calculate capacitor bank sizing and determine exact amperage reduction.
Ohm's Law & Power
Calculate Voltage (V), Current (A), Resistance (Ω), and Power (W) using standard DC theory.
IP Code Calculator
Determine exact protection levels against solid particles, dust, and water for enclosures.
Client Success & EICR Portal
Interactive observation decoder for clients to understand electrical safety reports.
Consumer Unit Hazard Diagnostic
Public safety self-audit wizard. Step-by-step visual diagnostic for homeowners.
Landlord Compliance Tracker
Calculate statutory 5-year expiration dates and track strict 28-day remedial deadlines.
Part P Notifiable Works Checker
Domestic Legal Compliance & Building Control Wizard for electrical works.
EICR Guidelines Client Preparation
Essential preparation guide for clients before an EICR inspection.