Reference Tables & Guides
Quick reference tables and guides from BS 7671:2018+A2:2022 (18th Edition) — 52 guides
BS 7671 Design Tables
Core tables for circuit design and cable sizing
Max Zs Tables
Maximum earth fault loop impedance values for MCBs and fuses with 80% testing limits
Cable Current Ratings
Current carrying capacity (Iz) for common cable types by installation method
Correction Factors
Derating factors for ambient temperature (Ca), grouping (Cg), and thermal insulation (Ci)
Voltage Drop Tables
mV/A/m values for calculating voltage drop in cable runs
References
Table 4D1BTable 4H1BTable 4J2B
Includes
CopperAluminiumSingle-phaseThree-phase
Testing & Inspection
Test procedures, limits, and certification guidance
Insulation Resistance
Minimum IR values from Table 6.1, test voltages, procedure, and interpreting results
Safe Isolation Procedure
Step-by-step safe isolation guide with GS38 requirements and lock-off procedures
EICR Codes Guide
C1, C2, C3, and FI classification codes explained with examples and overall assessment
Earth Fault Loop Impedance Guide
Zs & Ze testing guide with max values, 80% rule, earthing systems, disconnection times, and remedial strategies
PAT Testing Intervals Guide
Risk-based testing frequencies, equipment classes, test limits, landlord obligations per IET 5th Edition
Electrical Testing Sequence
Dead and live test order for initial verification and EICR, instruments, pass/fail limits, and common mistakes
Equipment & Components
IP ratings, MCB curves, and gland selection
IP Ratings Guide
Ingress protection ratings explained with common applications
MCB Time-Current Curves
Type B, C, D MCB tripping characteristics and selection guide
SWA Gland Sizes
Gland selection chart for SWA cables — CW and BW gland types by cable size and cores
RCBO vs RCD vs MCB: Complete Comparison Guide
Understand the differences between MCBs, RCDs, RCBOs, and AFDDs. Selection guide with BS 7671 requirements, comparison tables, and circuit protection recommendations.
References
BS EN 60898BS EN 61008BS EN 61009
Includes
BS 767118th EditionProtection Devices
Motor Starters & Control Circuits
Guide to DOL, star-delta, soft starters, and VFDs with wiring diagrams and selection criteria
Cable Types Selection Guide
Guide to cable types used in UK installations — T&E, SWA, FP, MICC, SY, and flex cables
Lightning Protection (BS EN 62305)
Lightning protection systems — risk assessment, protection levels, and installation requirements
Electrician's Toolkit Guide
Essential publications, hand tools, power tools, test equipment, and calibration requirements for UK electricians
Regulations & Compliance
18th Edition, Part P, and certification requirements
18th Edition Guide
Summary of BS 7671:2018+A2:2022 — key changes, structure, and regulation numbers
Certificate Completion Guide
How to complete EIC, MEIWC, and EICR certificates correctly with test results and Part P guidance
Part P Building Regulations
Notifiable vs non-notifiable work, compliance routes, special locations, England vs Wales, and BSA 2022 penalties
Domestic Circuit Types Guide
Standard UK domestic circuit types — ring finals, radials, lighting, cooker, shower, and EV circuits
Consumer Unit Regulations (Amd 3)
Amendment 3 consumer unit requirements — metal enclosures, AFDD, SPD, and circuit arrangement
VAT Guide for Electricians
Complete VAT guide — tripartite framework, ESM zero-rating, blocked items, reverse charge, and registration threshold
Quick Reference
Colours, symbols, and abbreviations
Cable Colour Codes
Current and old wiring colours for fixed wiring, flex cables, and three-phase
Electrical Symbols
BS EN 60617 symbols for switches, sockets, luminaires, MCBs, RCDs, motors, and fire alarm systems
Electrical Abbreviations
Glossary of electrical abbreviations, acronyms, and trade terms used in UK installations and testing
Design & Installation
Containment, cable management, and installation techniques
Trunking & Containment Sizing Guide
Cable containment sizing for trunking and cable tray per BS 7671 Appendix 12 with cable factors
Electrical Formulas Reference
Complete formula reference — Ohm's law, AC impedance, parallel resistance, star-delta, three-phase power, cable sizing corrections, and adiabatic equation
Cable Management Guide
Best practices for cable containment, supports, bends, and segregation per BS 7671 and BS 6701
Conduit Bending & Back Box Fill
Conduit bending calculations, set dimensions, and back box capacity for standard accessories
Torque Settings for Electrical Terminations
Recommended torque settings for MCBs, busbars, connectors, and cable terminations per manufacturer data
Installation Checklists
Step-by-step checklists for first fix, second fix, new builds, domestic rewires, and CU upgrades
Specialized Systems
Fire alarm, emergency lighting, and data systems
Fire Alarm Systems (BS 5839)
Fire alarm system design, categories, detection types, and wiring requirements per BS 5839
Emergency Lighting Requirements
Emergency lighting design, duration, lux levels, and testing requirements per BS 5266
Detector Spacing Guide
Smoke and heat detector spacing, coverage areas, and mounting heights per BS 5839
Structured Cabling & PoE
Cat5e/6/6a cabling standards, PoE power budgets, and testing requirements per BS EN 50173
Smart Home Wiring & Automation
Smart home wiring infrastructure — KNX, Zigbee, Z-Wave, and structured wiring for new builds
Outbuilding Electrical Supply
Supplying outbuildings, garages, and garden offices — cable selection, earthing, and RCD protection
Energy & Sustainability
Solar PV, batteries, heat pumps, and LED lighting
Solar PV Installation Guide
MCS pathway, panel technology, inverter selection, DC cable sizing (H1Z2Z2-K), isolation, AC integration, SPDs, metering (SEG), and battery integration
References
BS 7671 Section 712BS EN 50618ENA G98/G99
Includes
MCS certificationDC cablingInverter typesBattery integration
LED Lighting Upgrades & Savings
Comprehensive LED guide — L/B values, thermal management, Approved Doc L efficacy, LENI method, dimming protocols (DALI/0-10V), and industrial retrofits
References
Approved Doc LBS 5266IEC 61347
Includes
Part L efficacyDALI/0-10VL-value/B-valueIndustrial retrofit
Battery Storage Systems
Battery energy storage systems — sizing, installation, earthing, and safety requirements for electricians
Heat Pump Electrical Requirements
Electrical supply requirements for air and ground source heat pumps — cable sizing, protection, and controls
Advanced Topics
Harmonics, protection coordination, and special locations
Earthing & Bonding Requirements
Complete earthing and bonding guide — TN-S, TN-C-S, TT systems, CPC sizing, and bonding conductors
Protection Coordination & Discrimination
Overcurrent protection coordination — discrimination, back-up protection, and cascading
Harmonic Currents in Installations
Harmonic currents from LED drivers, VFDs, and IT equipment — neutral sizing, derating, and mitigation
Bathroom Electrical Zones Guide
Complete guide to bathroom electrical zones 0, 1, and 2 under BS 7671 Section 701, including IP ratings, equipment selection, and installation requirements.
Special Locations (BS 7671 Part 7)
Special installation requirements for bathrooms, swimming pools, construction sites, and other locations
References
BS 7671 Part 7Sections 701-740
Includes
BathroomsSwimming poolsConstructionMarinas
Electric Heating Systems Comparison
Comparison of electric heating systems — storage heaters, infrared panels, underfloor, and heat pumps
Training & Exam Prep
18th Edition, 2391, AM2 revision and career guidance
18th Edition Exam Revision Guide
Revision guide for the 18th Edition (2382) exam — key topics, regulation lookups, and exam technique
2391 & AM2 Exam Revision Guide
Revision guide for 2391 Inspection & Testing and AM2 practical assessment
Electrician Rates & Pricing (UK)
JIB 2025-2028 settlement, regional rates from 100+ locations, qualification hierarchy, CIS vs PAYE, and domestic job pricing benchmarks
References
JIB 2025-2028Industry data
Includes
JIB settlementRegional ratesCIS vs PAYEJob benchmarks
Using These Tables
For Design
- • Use tabulated values (It) for calculations
- • Apply correction factors: Iz = It × Ca × Cg × Ci
- • Use Max Zs values from design tables
For Testing
- • Apply 80% rule to Max Zs when testing
- • Compare measured values against limits
- • Document table refs on test certificates