Why won't an MCB reset? What's the difference between TYPE B and TYPE C MCBs?
ฝัง
- เผยแพร่เมื่อ 12 มิ.ย. 2024
- There are numerous reasons why it may not be possible to reset a miniature circuit breaker (MCB). Some are obvious others are related to the design of the installation and the electrical supply.
Joe Robinson explores further and introduces a new CPD module in partnership with Lewden.
Along the way we look at MCB types, MCB ratings and short circuit protection.
== 🕐 Time Stamps - Cut to the action 🕕 ==
00:00 Why won't an MCB reset?
00:30 Fault not cleared.
00:53 Breaking capacity exceeded (IcN)
01:50 CPD Module - MCB
03:43 What is the difference between Type B,C & D MCBs
== ===========================
🧰 More information.
CERTIFIED CPD MODULE - MCB Circuit protection
👉 www.efixx.co.uk/Know%20How/mc...
More LEWDEN content from eFIXX
👉www.efixx.co.uk/lewden-palazzoli
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❌ This content on this channel is for electrical professionals.❌ ==================================
📹 Presented by
Joe Robinson - Technical Editor eFIXX
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#efixx #mcb #circuitprotection - วิทยาศาสตร์และเทคโนโลยี
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These vids are so thorough and well edited well done Joe
Aw thank you so much. Glad you enjoy them! 😊
“Current subject.” Well done, Sir!
Thank you again! Yet another subject that is rarely (sic!) properly explained during (some) college courses - and a proof of this is the lack of understanding, among trainees and sparks alike, of what in fact is the difference between B,C,D types. Excellent video on a subject very much needed.
One of my MCBs wouldn't reset after it had been manually turned off. When I did a Big Clive on the bugger, I found that it was full of grit and bits of plaster. The eejits who installed the CU made absolutely no attempt at sealing the ceiling back up above it, or in fact the massive hole they cut in the top - so all sorts of shite was dropping into it, and must have found its way into the mcb.
I'll have to save that one for the sequel!
Thanks Joe and efixx, I did the CPD last night and it was really informative. I got a lot from it.
Great 👍
Excellent explanation Joe. You also can't switch them back on when they're defective by age. In that case they'll also trip even if there's no fault in the circuit or faster as they should. Also if the impedance of the grid changes massively this will cause issues. Here in Germany back in the old days we used type H MCBs for households, the grids had a high impedance back then. The type was manufactured until 1976. The short-circuit trip was between two and three times the rated current, so comparable to modern Z type. But the grids impedance became lower since then, and in combination with appliances with a higher inrush current, like a PC for example when the capacitors in the power supply are drained, the MCBs tend to trip. The age, the appliances and the lower impedance of the grid in combination makes them trip more often. The only thing that will help is the replacement of the MCBs, after that long period of time they reached the end of their lifetime.
Brilliant information, thanks for commenting. 😊👍
Well explained Joe
Nicely presented reminder
th-cam.com/video/GI49f9y4gOg/w-d-xo.html
Thanks very much. 😊
Very well explained 👍
Hope you try the CPD
Think you channels great and great job with what you do
Thanks very much!
Nice summary.
Thank you! 😊
Excellent.
Great video 👍
Thanks!
What does the number 3 in the box mean below the rated short circuit current on those MCBs?
How do we know if this is the case? I have never herd of the second value.
Fantastic video Joe very well explained
Thank you
See, for example, section 3.5.3 of GN 1.
It'd be a good idea to measure the prospective fault current after the fault's been cleared to see what current was likely to have flown when the fault occurred. Great question. 👍
Hi...Thank you for wonderful videos. The CPD link is not working for me..Webpage is not going further from captcha
Should I use a C type MCB at my home to play it safe?
I installed one a few days back and it tripped. It doesn't get switched on again and automatically falls to the 'off' stage. I know i must be replacing it, but is there a better alternative to avoid such quick tripping?
General rule I use b for general domestic , c type for banks of fluorescent lights and d for motors , was in a certain diy store and heard the so called expert on hand say to a customer when asked what’s the difference between this b and c breaker his reply was the b is £10 cheaper
🤦♂️
Hi, just wondering the CPD course you do if I complete it them can they be used as off the job training for an apprentice? Will still work through them but just wondered.
Yes should form part of your portfolio 💼
@@efixx thank you.
Why the little line in the mcb why are them red in the on position and green in the off positions
LED drivers are renown for causing a B type to trip due to inrush.
BEAMA have now helped ensure the correct type of CB and number of LEDs installed, by issuing this guidance: www.beama.org.uk/resourceLibrary/beama-guide-to-circuit-breaker-selection-for-led-lighting-.html
True. 👍
Thanks John.
My type B 16A trips from inrush when i turn on the 240 to 110V transformer.
As far as I know, there are MCB available in types A, AC, K, S and Z. I have used A and AC myself in a domestic 3 phase install. As an example take the Siemens device 5SM2345-0 (4P 63A Curve AC MCB -not MCBO). Otherwise useful. Thanks.
What country do you work in?
K is an old german type, but still in use and in the european standards and regulations. Stands for "Kraft" (power or strength). High inrush current, but low overload capacity. And that's the difference to B or C, they both only differ in the short-circuit tripping system, but the overload trip is the same on both.
Type A is a Siemens specific type, not normalised. Short-circuit is same as type Z, overload the same as B or C. Type Z is for high impedant grids, trips between two and three times the rated current (B: 3-5, C: 5-10 times), but the overload is only 1.05 to 1.2 times the rated current for one hour.
Back in the old days we had several types, also manufacturer specific ones like the A or R for Rapid (Moeller, now Eaton) which is identical to modern Z. S was also a Moeller specific type, comparable to D. S was "Steuertransformator" (control transformer). Common in households were the types H and L.
H for Haushalt (household), short circuit like Z (2 to 3 times) but overload between 1.4 and 1.75 times the rated current for one hour. H was manufactured until 1976, but is still found in old installations here. Was replaced by L, first for Licht (light) later as Leitungsschutz (cable protection). L is for the short-circuit part the same as modern B (3 to 5), but overload the same as H. Was installed until 1990, then replaced by the modern types like B.
Interesting stuff, thanks. 😊
@MarcelGerrman. Thank you for all these details - good stuff.
@Omega Maestro. I mostly work in rural southern france where TT 3 phase 230/400V at 64A (max) is a common supply.
@effix. I always watch your videos - even if I'm not interested in the particular subject. I appreciate all the effort you put in.
@@adrianandrews2254 And here in Germany it's usually TN-C-S or TT, in my area it's TN-C-S. But also three-phase 3x230/400V, 63A. For houses with electric night-storage heaters it's usually higher (80A). But now these days no one installs them anymore, and the old ones becoming replaced by gas or oil fired boilers with radiators in the rooms (forced hot water heating).
Funny .. C-Curve seems to be the standard in Belgium for Domestic .. B Type curve isn't common ..many wholesalers don't even stock them .. and they cost more then type C but are allowed :-) I know in holland B is also standard for residential .
Great info thanks 🙏
I have all 16 breakers on my panel type C. I live in Finland.
just push that 100a breaker back in service with your finger. what could happen anyway
I was taught that an easy way to remember what Ics and Icn mean is that Ics is "I c it's ok for continued service" but Icn is "I c it's nackered". 🤣
Ah man! Where was this before I shot the video! 🤦♂️😂
I C it’s Sound 😂
Looks like someone needs to go through the CPD module 🙄. Moi.
It's a really fascinating one. 👍
If you have a microwave that turns the power on hard, then a type B breaker may turn off every time.
Maybe the breaker was old and other devices were on, but a new type C breaker with the same rating helped.
(C 16 amps 1.5 mm2 not ring)
That's interesting, I had the same issue with a chop saw on my old house, swapped the B16 for a C16, problem solved.
Something to remember is that the fast trip points are defined as a multiple of the rated current.
So a C16 has similar fast-trip characteristics to a B32.
Oops - RCBO !
Could be cheap and nasty MCB.