Guidance Note 3: Inspection & Testing (Electrical Regulations)

Product Information

Predicted measured resistance = r y//r g = 0.5762×0.4264 ÷ (0.5762+0.4264) = 0.2451 Ω Step 3, resistance at Test Point 6 Fire alarm and emergency lighting systems are required to be inspected in accordance with BS 5839 fire detection & alarm systems for buildings and BS 5266 Emergency lighting, code of practice for the emergency lighting of premises respectively. Electrical installations open to the public may be subject to licensing conditions which dictate the frequency of inspection and testing. For a cinema an interval of between one and three years would be typical, whereas a petrol filling station or a caravan park will generally be required to be subjected to inspection and testing annually. However, these answers need to be presented in written prose, so will take a substantially longer time to craft than multiple-choice responses. Furthermore, responses need to be well-structured and flow smoothly, so there needs to be an element of preparation time also factored in. Delegates will be expected to incorporate relevant electrotechnical terminology in their answers. This should be extracted from both pieces of literature referenced earlier (IET wiring regulations and Guidance Note 3). However, this is a closed-book exam, and therefore candidates will not be permitted to refer to these during the test.

It was noted that those testing RCDs in the field would find it difficult to carry out the variety of tests permitted and may not know which of the available tests would be applicable to a given make or type of RCD.

If available, previous inspection and test documents should be sought prior to starting a periodic inspection and test as they are an important resource in detecting any deterioration of an electrical installation. The written exam is perhaps the most difficult segment. Therefore, it may be worth prospective participants practicing their written style (and handwriting!) prior to conducting the examination. Remember, these questions demand the incorporation of industry-recognised terminology in your responses. The terms expected to be utilised are denoted in the IET wiring regulations ( 18th edition), and Guidance Note 3 (inspection and testing). As this is a closed-book exercise, ensure you’ve familiarised yourself with this literature, in detail, before heading into the exam. Lastly, it’s also worth noting that multiple-choice exams can sometimes be a little misleading in terms of difficulty level. Some questions will require candidates to methodically work through a number of sums, formulas and information to arrive at the correct answer. Therefore, responses won’t always come purely down to technical knowledge, and may require considerable time and focus. By calmly and competently applying the right electrotechnical process or algorithm to each option, delegates can offer the correct response through a process of elimination. Written examination Further information on RCD testing can be found in IET Guidance Note 3 Inspection and Testing and PD IEC TR 62350:2006 Guidance for the correct use of residual current-operated protective devices (RCDs) for household and similar use which states that ‘ The testing current should be applied between the upstream and downstream terminal of the RCD’, see Figure 4 extracted from IET Guidance Note 3 Inspection and Testing.

a person who possesses, as appropriate to the nature of the electrical work to be undertaken, adequate education, training and practical skills, and who is able to perceive risks and avoid hazards which electricity can create.’ A typical spec is more like this maker's data for the LTW 425 - and that is a dedicated loop tester, not a compromised design to make a multi function tester all fit in one box, they tend to be worse.

Guidance Note 7: Special Locations, 7th Edition

There is an extra level of qualification and competence achieved, beyond the standard four-year vocational route commonly followed by qualified inspectors and testers.

It was therefore agreed that the testing procedure could be greatly simplified and safety would remain unaffected since RCDs are, in any event, tested extensively by manufacturers prior to sale. What are the changes to the requirements for RCD testing? The requirements for testing RCDs have been simplified, a single test is all that is required to show compliance with the minimum requirement laid out in BS 7671:2018+A2:2022. Regardless of RCD type, the test is carried out using an alternating test current, applied at the RCD’s rated residual operating current I Δn, the maximum disconnection time is expected to be less than 300ms for a general non-delay type RCD. For S type time-delayed RCDs, the operating time should be 130 - 500 ms. Other kinds of RCD testing may be useful for fault finding purposes. However, it is important to remember that Table 3.2 is titled ‘recommended initial frequencies of inspection of electrical installations.’ The first important word is ‘recommended’, it is exactly that, a recommendation and not a legal requirement. It is also important to note that this is for initial frequencies for new installations. It is worth noting that for domestic rented accommodation and houses in multiple occupation, the recommended maximum period between each inspection and test is five years or change of occupancy, which is often overlooked. The whole spectrum of electrical tests is employed on the necessary circuits and devices including when appropriate… The written part of the assessment is particularly challenging due to the nature and construction of question sets. The themes and specific conditions captured in the first question of each, will correlate through to the second and third questions. This means that if the initial question is approached incorrectly, it could scupper responses for the remaining two. Therefore, although this is useful from a consistency perspective, it still presents delegates with a significant scoring risk. By ‘building’ question content up, examiners are looking to assess whether candidates have a firm grasp on sequencing and process flow. Candidate approachIt is not normally necessary to inspect and test every single circuit, point and accessory within the installation due to the size and the costs that may be involved. However, you should inspect and test enough of the installation to be able to form an educated opinion on its overall condition. This is an online test. Therefore, if students are sitting the assessment remotely, they’ll need to ensure they have ready access to an internet-enabled device. This is often labelled as the easiest part of the examination timetable, therefore candidates ideally need to acquire a high score in this assessment. This will give them a decent platform to take on the remaining, more complex, challenges.