The City and Guilds 2394 qualification is for practising electricians who wish to have a qualification that will enable them to inspect and test new electrical installations.It is also a level 3 qualification.This is combination with the City and Guilds 2395 course replaces the old C and G 2391. The course is a combination of classroom work and practical.


City and Guilds 2394 Assessments


There are 3 assessments for the City and Guilds 2394. These are:

  • Online multiple choice paper consisting of 40 questions. You have 80 minutes to complete the test. If you pass the online test then you do not have to take it again if you choose to do the City and Guilds 2395 course, as it is the same test. You will need to know your Guidance Note 3 very well and also have decent knowledge of your BS 7671.


Outcome Number of questions %
1 You have to understand what is required for completing the safe isolation of electrical installations and circuits. 7 18
2 You have to understand the requirement for electrical inspection and testing of electrical installations and recording the condition thereof installations 2 5
3 Understands the requirements for the safe testing of electrical installations which havebeen placed in service 9 22
4 Understand the requirements for testingcircuits which have been placed in serviceand may require isolation 7 18
5 The requirement for testing installations that have been energised 13 22
6 Understand and interpret test results 2 5
Total 40 100


  • A closed book written exam consisting of about 6 questions. You have 90 minutes to complete the written test and the date is set by City and Guilds. The test always starts in the early evening around 06:30 and finishes at 08:00, however from August 2014 the time allowed to complete the test will increase to 2 hours.

You can use this exam success book.This is also the book that City and Guilds recommend to maximize your chances to pass. Loads of people who have use it has passed and the type of questions you will get is laid out like in the exam.


Tips for passing C and G 2394 Written Test


  • Read the question properly. So many times people do not do the basics right and this is one of the biggest ones people slip up on.  “One question relating to an earthing conductor clearly asked ‘what would be confirmed by inspection…’ but many candidates included testing of continuity in their answers, thus indicating that the question had not been read fully”
  • Learn your IP codes and exactly what the ingress is. 1mm and larger than 1mm is a big difference. You will almost always get a question about IP codes
  • Answer the question with regards to the details about the installation they list. If they ask how you would perform an insulation resistance test and have mentioned there are electric motors, time clocks, light sensors etc. in the circuit the mention what you would do about those equipment before/during/after the test. Do not just memorise a generic answer and write down as if you cannot think differently.
  • In a 3 phase system you have to remember to multiply your PFC by 2 (technically 1.732). Many people who have not a lot of experience in testing might not always remember this. I know people who boast that they have been doing inspection and testing for over 12 years and I have seen them time and time again fail to multiply the reading. The reason you do this is to allow for the highest possible prospective fault current. In a 3 phase system this will be between 2 line conductors shorting.
  • Remember to use the correct symbols like Ω, V, A etc. If you just give a number as an answer then the examiner will not know what unit you mean and you will not get marks for your answer. So just doing 99% will not cut it.
  • Use the correct terminology. Earth wire? Bonding wire? The correct terms are circuit protective conductor (CPC) and Supplementary Bonding Conductor and you would be wise to learn all the correct term as you will not get the marks if you do not use them.
  • Learn your earth fault paths for the different earthing systems as they do like to ask them.
  • Study the different ways to test the resistance of an earth electrode of a TT system, and remember that you get a stakeless tester


Resources to help you pass your 2394 exam:

  • Chief examiners report. You can get it here. Read it and see how they want the questions answered and where cpass your C&G 2395 with GN3andidates are making mistakes.
  • GN3. Again this is the book the entire test is based upon. You need to know it and the only way to know the book is to read and study it in detail.
  • BS 7671. Even though you do not get many questions about your 17th edition you still need to know the information contained in it. You can find information about IP ratings, and your tables for Zs values(41.1| 41.2| 41.3| 41.4). This is a book any practising electrician who takes his job seriously should own.
  • Exam success book. As stated earlier this is the book City and Guilds recommend in order to pass the exam.


The C and G 2394 practical assessments consists of a few different tests you have to complete.

The 2394 practical assessments are:

Doing a visual inspection to the standards in BS7671:2008-amd 1 and Guidance Note 3.There are a number of faults on a list the assessor has and you have to identify the 12 faults he has on his list.

Some of the faults might be the following:

  1. The colour coding of the cables are incorrect
  2. Exposed live parts
  3. Incorrect circuit breaker for circuit
  4. Incorrect polarity
  5. The earth and neutrals are not terminated in the correct sequence
  6. The circuits are not labelled correctly or missing circuit chart
  7. No sleeving on bare earths
  8. Absent earth wires
  9. Missing protective bonding conductor
  10. Missing notices such as mixed colour codes and RCD quarterly test notices.
  11. Twisted cables
  12. The cable sizes are too small for the circuit and breaker
  13. Any damaged enclosures or equipment
  14. Loose wires from the Steel Wire Armouring

The main thing to remember is that it is visual only, so if you touch something to identify a fault, then the chances are that it is not the fault the assessor is looking for. Furthermore tugging on wires and the like will create other “faults” not on the sheet and doing this will create problems for other candidates who might identify false faults and end up failing the assessment.


Fault Finding by means of an insulation resistance tester


You will need to do a fault finding exercise on what is called a “black box”. This is fairly straight forward, but do keep in mind that the assessor changes the faults that you must find. Before starting the test you have to complete the usual pre-test checks on the tester, which are checking the tester for damage, seeing of the test leads are not damaged and compliant, that there is enough battery power and that the calibration date is not expired.

You then proceed to test:

  • Line to Earth
  • Line to Neutral
  • Neutral to Earth

The test results you can expect is an open circuit (>299M Ω), a reading under 2 M Ω (low insulation resistance), or a reading of 0 Ω (short circuit). You then need to identify these faults and suggest what could be a possible cause for it.


C and G 2394 Inspection and Testing Practical Assessment (2394-03)


You will have 2 hours to complete the entire test with the relevant paperwork on a test rig. The whole of the installation needs to be tested and all the paper work completed fully.

The City and Guilds 2394 test rig looks like this

City and Guilds 2394 test rig
Image courtesy

A 3 phase DB supplying:

  • Socket ring circuit
  • Radial circuit wired with MI cable and terminating in a fused spur isolator with a neon
  • DOL starter wired with a 3 phase SWA cable
  • Sub-main to a single phase DB

A single phase DB supplying:

  • Socket outlet supplied by a radial circuit
  • Lighting circuit with intermediate switching
  • Lighting circuit with a dimmer switch

The test procedure you will need to follow will be:

  1. Ask for all the circuit details and ask permission to isolate the installation.
  2. Lock off the isolator and place tag and put the key in your pocket.
  3. Prove your voltage indicator on proving unit, test that installation is dead, and re-test your voltage indicator on proving unit.

Do your internal inspections, and then continue to test:

  1. Continuity of protective conductors including supplementary bonding conductors
  2. Continuity of ring final circuit conductors
  3. Insulation resistance test for the installation.

If there are no problems at this stage then you can make sure that all the circuit breakers are switched off, and then you can proceed to re-energize the installation. You might be required to put the cover back on, then re-energise, and then take the cover off again. This is depending on the assessor you get.

  1. Now do the Ze test with the mains switch off, and by testing at the incoming terminals. Remember to mention the calibration, tests leads etc. are compliant.
  2. Reconnect the earthing conductor after the test is completed.
  3. The tests for PFC and PSCC can be done in the same manner.
  4. Because it is a 3 phase installation you need to take the highest reading you get for your PFC and multiply it by 2.
  5. To test the RCD you will need to switch the main switch on and the RCD, but nothing else.
  6. Then complete the RCD test at 0.5 X at both cycles, 1X at both cycles and 5X at both cycles and record the readings. Remember to press the test button as well.

Lastly you then need to replace all the covers, barriers and accessories to complete the functional tests.  This is just checking that the lights switch on sockets work etc.


City & Guilds 2394 Course Content:

Key areas covered include:

  • Reasons, requirements and procedures for safe of electrical circuits and installations
  • Why it is required to do initial verification of electrical installations before being put into service
  • How to perform safe testing safe testing and commissioning of electrical installations
  • Testing electrical circuits before they are energised
  • How to complete the electrical installation certificates and other related paper work for test results and inspections.
  • Safety of systems and equipment prior to completion of inspection, testing and commissioning
  • Inspection of electrical installations before they are to be used
  • Commissioning electrotechnical systems and equipment
  • Health and Safety requirements
  • Requirements for the inspection of electrical systems
  • Factors that affect conductor resistance values
  • Common earth fault loop paths
  • How to verify protection of circuits
  • How to determine fault current
  • Procedures to follow when dealing with clients

The 2394 is definitely a worthwhile qualification to have. You can then complete the C and G 2395 after this which will definitely make you more attractive to potential employers or if you plan to incorporate inspection and testing into your electrical business.