Hi Dave, thank so much once again. I just cant get enough of your well presented videos, simple explanation and well informed. your hard work will always be useful for many years to come. as an electrician, I have learnt and benefited a lot from your videos than my entire years I spent in college. I can proudly say my mental tool box is filled with better and clear understanding of electrical knowledge than just the RULE OF TOM. CHEERS DAVE...….!!!!! much appreciated
Great to know that and thank you for the brilliant comments. So good to know that videos are helping, spread the word. Thanks for watching, lots more to come. Dave.
Am currently installing a rotary phase converter in my shed to give me four three phase switched power sockets to run my wood working gear from a single phase input. Have been trying to work out how to size and select MCB's. This is by far the best presented and clearest video i have seen explaining MCB sizing and selection. Thankyou and keep up the good work.
thank you you helped me so much through out my L3 electrical, design project, 18 th edition, inspection and testing and now during my NVQ about to finish it and will go for the AM2 and you my good sir have helped so much with your content, theroy wise this is THE BEST ELECTRICAL CHANNEL ON RU-vid, GOD bless you and I hope many more content is produced so others can banefit from this channel, you deserve more views and subscribers SIIR!! , PLZ guys share, like and subscribe to this channel so more people can learn from it
Thanks for the video. Your earlier video on the "Magic 35" number is useful here for Zs values. Just shows that "the handyman" changing the breaker type may solve one problem but creates another. (Well spotted k higgins below - beat me to it).
Hello Dave, Speaking about the second method of solving inrush current and unwanted trips, I mean changing both type and rating of the MCBs. The example discussed does not seem to be a solution. If you replace a 32 type B MCB with a 16C , then both of them will have similar reaction for surge currents. But I got the idea and purpose. Thank you.
Yes, there are various ways and solutions Sajad. Its all a matter of selecting one that works. In the past with lighting I've ended up splitting the load across two MCBs. Keep watching, lots more to come.
Zs value requirements for 16 A is low isn't it ? So selection of 16 A is correct if load current is under this value. These lessons are for TN grounding systems I think .
Also dave would there be any chance of doing a video (unless you already have) on the leads for MFT the 2 lead high and 2 low etc and the 180o etc that’s one thing that’s in my head I need to understand 👍
Absolutely right Mervyn. My typo, some else pointed this out too, which is what I love about you guys - always keeping me on my toes. Thanks for taking the time to correct me, it really is appreciated, and thanks for watching. Dave.
Have a look at the video on the link below. This is about a different fuse, but explains exactly how to read fusing tables that you can then compare to the tables for Type C breakers in the brown wiring regs book. Hope this helps, Dave. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ojI7vX7u6_A.html
Question type C will trip at 10x it’s rated current , so in your example of 16A type B,C, and D Our MFTs only allow us to test at half times, one times, and five times the current rating, So if for example a type C trip’s at 10x we can’t test at 10 x so should we test at 5x then double the reading on our MFT? Ie 10x16a =160amp so testing at 5x it will be 80amp multiply by 2 give you 160 so long as that trips with in the specified times it will comply with BS7671 . This would also apply for other types as well ? Or am I wrong. Maybe you could do a video explaining how to test the different types . Great video very interesting and informative as always 👍👍❤️
I'm a learner so if this is wrong let me know. Dave is talking about MCBs here and the trip curves and characteristics for different types. MCBs react to overcurrrent and short circuit - he is not talking about RCDs which measures faults to Earth. You test RCDs by introducing small Earth leakages of 15mA, 30mA and 150mA (for a 30Ma RCD) and record the trip times.. The current rating on the RCD is just the current that the RCD can carry 24/7 without problems. Hope that helps.
Sean, this video is for MCBs not RCDs. We have to assume that the manufacturer has made it correctly and it will trip at x5 x10 etc. Out MFTs can't test at those currents. It would be too dangerous to have a meter output of say 1200 amps to test a breaker. We take it on trust hat the MCB will do its job if we get the Zs right. Hope this helps. dave.
Absolutely right GrumpyG. You're obviously learning well and its great that we all support each other. Thanks for your input and I'm sure that Sean appreciates it too. Dave.
