The process involves stepping up the voltage to minimize the loss of energy in the form of heat. Mains voltage test: (dead test) This test isolates the power supply serving the boiler, so as safe, further testing can be continued, without the risk from stray electrical currents causing a shock. It is more important than ever that industrial employers understand their legal responsibility to make sure their technicians are competent to carry out their tasks. Remember ! Look for any feedback given if you get an answer incorrect. A key thing to note about the AM2 though is that they will happily fail you for incorrect terminology. Loss of Supply Tripped CB – Blown Fuse – Internal Fuse, Potential cause:               1.Overload (time to trip or blow will determine the likelihood)                                      2.Earth Fault (does it re-engage)                                      3.Faulty device (is it operating functionally – opens and closes)                                      4.Dead Short – in real terms this could trip a circuit breaker for the circuit                                      that is shorted, & not the Main fuse. During the course of assessing more than 1,000 candidates over a 15 year period, MCP has found fault finding to be the second biggest weakness in maintenance trade tests. Fault-finding involves checking the sequence by monitoring the state of electrical outputs to solenoids and inputs from limit switches. Murray Loop Test Equation:        A/B = {L+(L-X)}/X. Looking at Figure 1 (other side of this sheet), the lighting circuit is seen to be ‘switched off’ and therefore it should be seen as safe to work within any of the modular fittings repairing or replacing parts – but on closer inspection it can be seen that the NEUTRAL is passing across the switch, not the phase, and therefore the phase section of the terminal block (and any part thereafter) remains live even with the switch in the open* position. Our courses have been delivered across the UK and around the world. These principles apply in all disciplines regardless of whether they are civil, electrical, mechanical etc. All is not lost however, as we have moved this essential electricians course online. Keep choosing an answer until you get it correct. Finally, look closely at Figure 3. Intriguingly in this case the use of a 100mA RCD as a main switch could well give rise to nuisance tripping throughout the life-span of the installation, because the discriminatio0n of the device would be seen to be incorrect. The delegate will be required to select the appropriate tester (insulation resistance tester) and after visually inspecting the tester for faults , setting it up for the correct voltage. Look for any feedback given if you get an answer incorrect. What are the six key steps to approach electrical fault finding? Electrician Training - A Systematic Approach to Trouble shooting and Electrical Fault Finding. The test involves wiggling the wiring to see if a fault occurs. Mostly seen in Industry Control Circuits (Internal Fuses) – Contactors (Breakdown of Parts)  – 3PH motors (Loss of  Phases &/Or burnt out coils) – Single Phase Motors – (Carbon Brushes), Initial Faults on newly Installed work Reversed Polarity – Discrimination – loose connections – Protective Devices –Faulty Portable equipment – (NB: Cannot be ‘ware and tear’). One end of the faulted cable is connected through a pair of resistors to the voltage source. With more sophisticated equipment or systems it may necessary to ‘fine-tune’ the system in order to return it to optimum working conditions. Cable Fault Finding – Decay Method. The healthy side can now be disregarded and the half-test carried out again on the damaged side of the circuit. It is always worth remembering that Motor & Control Circuits often contain Internal Fuses –  & what may seem like a loss of supply could be an internal fuse having blown. Electrical Exam | Electrical Training for Bright Sparks. Understanding the importance of multi-skilling your engineers is the first step towards addressing any skills shortages you may have. State and record how the identified faults can be rectified. Introduction. What other benefits can a multi-skilled workforce bring…. Testing to locate the position of a Fault. Here, John Saysell, Head of Business Development and Technical Training at MCP Consulting Group, explains his Six-Step Approach to Fault Finding…. In figure 2 (other side of this sheet), the problem with, Potential cause:               1.Overload (time to trip or blow will determine the likelihood), 3.Faulty device (is it operating functionally – opens and closes), 4.Dead Short – in real terms this could trip a circuit breaker for, Type C/Type 3        Motor Circuits – Inductive Loads. I passed my Trade Test in 1980 and have been involved in the Electrical Trade since then with a large number of years as an Electrical Contractor catering for both Domestic and Industrial sectors. It's annoying if an electrical socket or appliance doesn't work. When electrical energy is generated in the generations’ stations, it is distributed to the different loads, i.e. Finding Electrical Faults. From the above, if a reading of 0.00Ω was seen, then the two cables being tested are in contact with each other at some point in that circuit. At supply Origin – at a single outlet (Phase Neutral reversed or neutral earth reversed) or at a single fitting (Phase – Neutral) – Live Test Vs Dead Test. Industry Control Circuits often contain Internal Fuses – what may seem like a loss of supply could be an internal fuse having blown. the fault is removed) this will not be of much use if the cause of the puncture in the first place is not determined and appropriate action taken. Troubleshooting is the process of tracing and rectifying faults in electric/electronics circuit. If a Low Ω reading were obtained at that point this would indicate reversed polarity, and must be investigated further. One side would read >999MΩ, and the other would continue to read 0.00Ω. Answer ALL questions. Definition of fault finding. Here are six key points to consider: 1. Online Fault Diagnosis Test – Practice Test Download Fault Diagnosis Test – Practice Test. It is important to ensure that the machine, equipment or system is functioning normally after the cause of the fault and the fault itself has been dealt with. Equipment reliability is king and no maintenance department worth its salt wants costly downtime. This may be a simple task, as in the case referred to above, or it may be a much bigger one. Reject it afterwards at the first opportunity if it clearly is not relevant. 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Devices shipped with integral Ground Fault Interrupting cords (such as blow dryers, etc.) The testing equipment used to detect faults in the operation of electronic devices by creating stimulus signals and capture responses from electronic devices under test is known as electronic test equipment. Note 1* This is why ISOLATION is much more preferable to switching off for maintenance – breaking both poles would eradicate the risk in this case, although the problem would still be in place. The first rose is wired correctly & how would be expected, although the second is a complete wiring confusion, with the lamp wired across the Neutral and the loop and no wiring in the switch-plate. Newly Installed work – CB’s tripping once power is energised. VLF Sheath Test Voltages. The areas or regions are systematically reduced in size until a specific part can be identified as being faulty. From the above, if a reading of 0.00Ω was seen, then the two cables being tested are in contact with each other at some point in that circuit. The feedback from delegates about their feeling safe and relaxed while undergoing training has been outstanding to date, so we look forward to seeing you soon on one of our courses at DJT. This must be removed. If none is seen (ie: open circuit, > 200Ω), then the test would be moved to the N – E of the same termination point. For shielded cable, insulation is used to limit current leakage between the phase conductor and … Hopefully the installer will have some indication of the most likely ‘trouble spot’ area within the installation that any fault (earth of short circuit) may have occurred once the Main DB is commissioned and the circuits are switched on – eg: a spur off a ring that was difficult to terminate at the 2nd Fix stage, or a multi-gang switch that had a number of 2 and 3 core cables in the same enclosure, and seemed constricted when the face plate was screwed on. An earth fault on one phase of a 3 phase supply will disconnect. This condition is verified (or tested for) by utilising the R1 + R2 test method of linking the Phase to Earth at the DB and testing at the point where a reading would be expected between PH-E. Hi I have my fault finding resit in a couple of weeks. This is a skilled analysis using a dedicated meter which incorporates a number of variable resistors and an ammeter. Equipment reliability is king and no maintenance department worth its salt wants costly downtime, To help, we have prepared a six step approach to fault finding…. All of the faults are either open circuits, short circuits or incorrect polarity, and most faults are found using simple continuity tests rather than the full range of diagnostic tests. You will be presented 7 random faults to investigate and diagnose. For further resources, why not check out our video support library and our electrical testing & electrical safety blog. Find a local electrical school. Incorrect Polarity in fixed Electrical Installations could give risk to electric shock where a circuit is thought to be switched off, when in fact a live terminal remains within the fixture. Reject it afterwards at the first opportunity if it clearly is not relevant. This fault can be traced with continuity test. One side would read >999MΩ, and the other would continue to read 0.00Ω. Once you learn the symptoms of each it should become straightforward to resolve the issues you will encounter... Loss of Supply  Why (Loose Connection – Tripped CB – Blown Fuse – Internal Fuse), Earth Fault  Tripping Circuit Breaker/RCD – device will not re-engage (or will for a short while - then possibly a switched circuit contains the fault), Dead Short  Phase to Neutral/Phase to Phase – has the main fuse at origin blown, Correct Protective Device in place  Type B – Type C – Type D Circuit Breakers / S’Type RCD’s, Defective Components  Switches – Relays –Contactors, etc, not functioning correctly (brings about the decision as to replace or repair), Breakdown of Control Circuits  Internal Wiring/PCB’s & Electronics (How far to go for an ‘electircian'). You will see in Figure 2 that they are correct from the Main Fuse to the primary intake at the kWh meter, but the secondary side has been wired with the Phase & neutral the wrong way round. If you are convinced that the Earth is touching the phase (or vice-versa), or the PH is touching the N prior to the load, then you would carry out an IR test at 500 Volts DC between the Ph & E or Ph & N. If a reading of 0.00Ω was seen, then the two cables being tested are in contact with each other. Further reading: Become an Electrician Control Circuits often contain Internal Fuses – what may seem like a loss of supply could be an internal fuse having blown.  In this way, home in on the problem component(s), and replace it(them), observing all safety procedures. My company became known as the specialists in fault finding on machinery. Whether they’re working on tanks in the armed forces or repairing a city bridge, technicians, civil engineers, and security personnel need to know how to spot and quickly fix equipment. Some of these boards have switched faults on them so that the candidates start to gain some fault finding experience. We talk to Dale Biggs, Upstream Production Manager at AG Barr, about how training delivered by MCP is equipping shop-floor staff with invaluable maintenance skills to keep production lines moving. While these are effectively carrying out the same job, the fuse is part of an isolation device, which is in place for a different purpose to the Circuit breaker at the DB. Once you learn the symptoms of each it should become straightforward to resolve the issues you will encounter... Why (Loose Connection – Tripped CB – Blown Fuse – Internal Fuse), Tripping Circuit Breaker/RCD – device will not re-engage (or will for a short while - then possibly a switched circuit contains the fault), Type B – Type C – Type D Circuit Breakers / S’Type RCD’s, Switches – Relays –Contactors, etc, not functioning correctly (brings about the decision as to replace or repair), Internal Wiring/PCB’s & Electronics (How far to go for an ‘electircian'). If any faults are detected, then identified faults can be traced an rectified using electronic … Consider all the evidence collected and, if possible, reject any which after further careful consideration is not relevant. But with a bit of logical detective work, you should be able to find the cause of the problem - and, in many cases, correct the fault yourself. One side would read >999MΩ, and the other would continue to read 0.00Ω. An earth fault on one phase of a 3 phase supply will disconnect that phase – while the remaining two exert to rotate the apparatus. If the initial reading were less than the maximum for the instrument being used and continued dropping as the test were being carried out, part of the circuit would be seen as erroneous, and must be further investigated using the half test method. From Fig 1 above, if another five 500watt halogen fittings were added to the circuit controlled by the 13A fused spur, the fuse in the spur would (eventually) overload. Cable Fault … Discuss Fault finding in the am2 in the Electrical Forum area at ElectriciansForums.net. Observe the system running, if you consider it safe to do so. This definition supplements the requirements already mandated by Sections 43 and 44 of the Electricity Safety Act 1998. In a sense this is a continuation of the process of ‘analysis’. How to identify electrical faults. Hopefully the installer will have some indication of the most likely ‘trouble spot’ area within the installation that any fault (earth of short circuit) may have occurred once the Main DB is commissioned and the circuits are switched on – eg: a spur off a ring that was difficult to terminate at the 2nd Fix stage, or a multi-gang switch that had a number of 2 and 3 core cables in the same enclosure, and seemed constricted when the face plate was screwed on. The healthy side can now be disregarded and the half-test carried out again on the damaged side of the circuit. To help our students prepare themselves for their online exams, we designed an electrical courses exam simulator, for all of the electrician courses that we offer. Intermittent wiring faults occur because of dirty or poor connections, internally broken wiring and damaged wiring insulation. Some of these also have switched faults. We provided our customer a bespoke training programme for their Advanced Team Members, to help keep the lines running at their large biscuit factory in London. All solenoid valves should have an indicator in the plug tops to allow electrical signals to be observed local to the valves. This will require more power when a restriction is in place & thus create an overload situation. Fault finding means the testing of the operation of electrical equipment to determine if that electrical equipment is safe and working correctly as defined in the Victorian Electricity Safety (Registration and Licensing) Regulations 2010.. To locate the point the circuit must next be disconnected as near to its mid-point as possible. General It is important to note that DISCRIMINATION is ensuring that the correct device operates when a fault or overload occurs – not, as many mistakenly take it, the nearest or smallest device. Theoretically, if a Dead-Short occurred across the cable supplying the Fused spur the Main fuse would operate, although if the halogen lighting brought the load protected by the 32A ring to a figure in excess of its 32Amp rating the CB would disconnect (in due course), etc, etc... so discrimination describes the correct device operating at an essential time in the event of either the cable or the load being rendered unsafe. Cable Fault Finding Solutions. In this case if the wiring were terminated across a one way switch, it would not in fact turn the lamp on and off – the lamp would be perpetually receiving a phase and a neutral, & therefore stay ‘on’. This Electrical Career Now free practice test covers electrical theory, electrician trade knowledge, wiring, installation, safety, load calculations, and more. One of the most important factors in doing this, is the approach used. This will require more power when a restriction is in place & thus create an overload situation. Open Circuit - A connection may be broken i.e. This type of reading often indicates the connection between PH to E is less substantial – possible one strand of wire or a fraction of a cable in contact with a screw.  Take measurements around the circuit, but mentally predict what they should be. Fault finding and rectification - advanced, test instrument settings, readings, test procedures, typical faults, supply faults, fault-finding procedures - 8 questions from a bank of questions . 2365, 5357, 2391, 17th edition & 18 edition. All the evidence collected must be relevant to the problem in hand. 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