- A4 PDF · 128 pages
- 2391-52 practice
- BS 7671:2018+A4:2026
Inspection and Testing Calculations
Practice Questions with Full Worked Answers
Calculation practice for the 2391-52 inspection and testing assessments and for on-site testing. For use with BS 7671:2018+A4:2026.
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Written by a City & Guilds 2391-51 qualified electrician.
What is inside
What you get
Calculation slips cost marks in a written assessment and confidence on site. This workbook gives you graded practice on the calculations used in initial verification and periodic inspection, with the formula, the numbers and the result shown for every answer.
- 200 questions in 14 sections, graded Easy, Core and Challenging
- Continuity of protective conductors, ring final circuits, earth fault loop impedance and temperature adjustment
- Prospective fault current, insulation resistance and RCD test results
- Voltage drop, design current and cable selection, the adiabatic equation, TT earth electrodes, maximum demand and power factor
- All the data each question needs is given in the question, so you practise the method rather than looking up tables
- Every numerical answer was calculated by computer and checked by a second, independent calculation
- A short method page at the start of each section and a two-page formula sheet
- A squared working box with every question
At a glance
- Format
- A4 PDF, 128 pages, clickable contents. Print the pages you need.
- Questions
- 200, in 14 sections, graded Easy, Core and Challenging
- Answers
- A full worked answer for every question
- Edition
- For use with BS 7671:2018+A4:2026
You do not need BS 7671 to work the questions: all the data each question needs is given in it. Conductor resistances, voltage-drop figures and some cable current ratings used in the questions are typical published values for copper cable, given so the questions can be worked; always check against your own copy of BS 7671 and the manufacturer’s data. No figure in the book may be used for design, installation or certification.
Contents
Contents
Front matter: how to use this book and a two-page formula sheet. Then 14 sections, each with a method page, followed by the worked answers.
- Ohm’s law and power
- Continuity of protective conductors
- Ring final circuits
- Earth fault loop impedance
- Temperature adjustment
- Prospective fault current
- Insulation resistance
- RCD testing
- Voltage drop
- Design current and cable selection
- The adiabatic equation
- TT systems and earth electrodes
- Maximum demand and diversity
- Power factor
Sample pages
Pages from the PDF
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