Your video excellent. One suggestion. In your example, kindly put only one Refrigerator., instead of 2. In 99.999% of Indian homes, we will have only one Refrigerator.
Good explanation ! Although you mention that B-curve (meaning RCB type B) is used for lighting, i see in all home installations only C-curve MCBs are used. Why is it so ?
C- Curve is tripping at 2 times of current. Do you have any video examples how these MCB trips or do you have tested these tripping's at your end. This seems like a theory that D-curve will trip 10-15 times of current. My question is that did you ever observed this in your testing's.
Sir I think as per IS, max wattage that can be connected to a lighting circuit is limited to 800W. So we need only 6A MCB.. Here no calculation required..
By this calculation, my 2000w geyser should be needing more than 10amps MCB. But in my home, i have C6 amps mcb which is working fine. last i used 2000w geyser and 1400w heater at the same time, then only it tripped after 3 4 minutes. due to some problem in my area i am only getting 170 180 v mains which should theoretically increase the amps. But still every thing is working fine on 6amps. can you explain why?
It's not that a mcb of 6amp will trip when lode rise above 6 amp. C type mcb will trip when the load current rises 5 to 10 times of the rated current. So a c6 mcb will trip on around 30 to 60 amp
@@Bishalkarn that’s not quite right. The curve relates to how quickly a mcb will trip with the current in question. It’s not a 5x and that’s that. If you look at the manufactures of the mcb they will have a graph where you can see the curve on a graph and the time it takes to trip. The higher the current the quicker it trips. So if you pull 8 amps through a 6amp mcb it should trip eventually but will take a bit of time. The curve is in response to standards set down as to how long a mcb should take to trip because the cable it’s protecting can take a certain amount of current for a certain amount of time. The longer you run the cable the hotter it gets. The issue is different types of loads pull different amounts of current. So a motor will pull a lot of current when it starts but once it’s running it pulls a lot less. So if you put a type b 10 amp in and the motor is rated at say 8 amps you’d think it would work but it may pull say 90 amps for .5 of a second when it’s starting. That may trip a type b and you have nuisance tripping. The type of mcb selected should be based on the type of load going on the circuit. The size of the mcb should be based on the maximum current draw and the size of the cable should support that calculation. I’m not sure what is in this video matches what is in the uk. But I’m not an electrician but I think the .8 calculation is about diversity which is related to likelihood of all the loads being on and pulling their rates current at the time. I think this is applied after the loads are calculated. Not sure I’ve seen anything about 1.5 or 2x and you only apply diversity in specific situations. Like I said this is what I understand of the uk electrical standards which can change on each edition of the British standards and I’m not an electrician.
@@davideyres955 Thanks for you contribution. i guess it makes sense. The previous comment is also right in a sense. i checked and found that indeed type c can go upto 5 to 10 times, but time is also a factor. Guess some electrical engineer can clear these things in future comment.
2000 W geyser takes around 11 Amp and if you use 6 A curve the MCB will trip within 15 minute.. Here the thing is that geyser will automatically cutoff when the temperature of water reach a specified value.. I think it will be less than 15min.. Please remember that if you provide geyser in a 6A socket surely the socket & Switch will heats up.. This will reduce the life span of that Lighting circuit.. So plzz don't do this..
