I have found the trapped insulation problem and loose terminals within pre wired connector blocks on outdoor lighting accessories from the well known DIY suppliers. Check all screw connections, saves getting the ladder out twice!
I did a lighting circuit fault find 2 weeks ago. Customer complained of a burning smell and coming after he switched on the lights and then the lights tripping. After a few investigation we lifted up a floorboard to get acces to a joint which I couldn't get to from the light fitting, and saw a huge rat had clamped onto the switch wire. The burning smell was the rat cooking when the current was flowing through him. There were also live maggots eating him out 🤢🤢🤢🤢.
Odd one here, 3 core and earth on bathroom fan. After fan isolator, switched live only giving 130v, perm live happily giving 230v. Any ideas? Neutral fault???
Remove the wiring from the fan (after drawing how it is wired) and check each conductor. If your earth is good, then a voltage check earth to each wire should show either zero volts or 230 volts ish. Flick the switch and see what voltages change.
Hi, dave. During a consumer unit change and when doing a live test, I found out that the earth was live. I could test 14V coming from the earth but the RCBO did not trip. What can be the cause?
Thank you Dave. I have got a question about insulation resistance test on lighting circuit. When there is so many spotlight oncircuit, some electricians do the test bu 250 rather than disconnecting all light and doing 500v test. Some connecting line and neutral and just doing test between them and earth. Is it right way? Does it comply with regulation? Sorry if you find it irrelevant question.
Mohammad, take a look at this video, some testing methods changed with Amendment 2 and this video will explain. AMENDMENT 2 - 18th EDITION - INSULATION RESISTANCE TESTING - CHANGES - click on the link ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Kly-q-DShxA.html
Hi Robert here not Angela lol, another excellent video especially the large easy to follow diagrams. One thing though am i correct in saying that on a1 way light switch the brown live wire on the switch cable terminates in the common but on a 2 way or 3 way lighting configuration that same brown wire terminates in L1 and the black strapper cable from the 3 core goes into the common and also either gets carried on through to the common on the either 2nd or 3rd switch depending on the set up. Its remembering this which is tricky i guess it comes with practise thankyou so much your videos are a godsend they really are.
Absolutely brilliant video typical and common faults which you will find on a daily basis when being called out to fault finding on luminare circuits. Nicely explained and very methodical method which I follow. Thanks Dave keep these great video's coming much appreciated and wanted.
Can someone please fo a video regarding the blue wire. The fact that its earthed at points along points back to the power station. And that ac curent moves down the blue wite but doesnt short to earth?? Nor do the earthed parts of the installation become energized yet are connected to earth and thus to neutral and ac current flows 'back' up the wire on the negative peak of the sin wave?? Please coz its not looking safe on paper or logical to connect earth to neutral
Neutral and earth are physically bolted together back at the substation so the same electrical potential. There is (about) zero volts difference between them. But yes, maybe a video could be done.
@@learnelectrics4402 please do, no one has adressed this phenomenon. If the current changes direction ( alternating current) then at least 50 times a second the blue wire should behave excactly as the brown wire does. And thus energize all earth bonding if the flow is coming in from both live conductors . Why is the electrical pressure only registered on one wire if they 'alternate'??? Need to know. And thank you for sharing your knowledge in the community.
Thanks again for the video. I may be wrong here, but at 3.09 you say "the current flows through the switch to the common terminal and up to the switch block". Your diagram shows the switching line coming from L2 to the switch block?
My bedroom light randomly cuts out. I've had a sparky look at it and we've changed the pendant and switch, but couldn't find anything wrong and it is still happening and thoughts?
Fantastic video Dave as always 👍 I have come across most of these faults at some point in my career. Mostly as a result of DIY . I don’t see them at all these days. Maybe that’s a sign the DIYers are leaving the electrics alone and sticking to putting shelves up . Thank you you reminding me with another good brain work out.👍👍❤️
3rd year apprentice here, very helpful video, I wish this was explained to me in this way when I first started as this would have been a catalyst to my learning. Thank you.
Thank you Dave for the detailed explanation. If possible, I can communicate with you to discuss some questions related to street lighting circuits, as I have been working in this field for a long time and I face some technical problems due to the inability to understand how to choose the appropriate method to protect these circuits and people from electrical hazards. One of the problems is, if the luminaires are LED type and feed by a 3phase (4by16mm2) cable system. Is it ok or not to use the armor of the (4by16mm2) cable as a cpc instead of a copper cpc to reduce the cost of materials?. The second question: is it a must to use an RCD in addition to the circuit breaker in these circuits?
Steel armouring has only about 12% electrical conductivity of copper. Generally, it is accepted that the armouring of a cable has an equivelant conductivity of the copper cores. So, 16mm cores, the armour is equivelant to 16mm copper. If you need a bigger size earth you will need to run a separate cable. If the regulations for street lighting say use an RCD then you should be using an RCD + MCB or RCBO. If something goes wrong and people are injured, you will have to explain why you did what you did. Thanks for watching.
