You have very good understanding of each and every factor....superb dedication...........I have been working in industry as an Engineer,I want read articles related to industrial technology can you please suggest me any source.... Thank you... May God bless you..
of there is Circuit breaker short circuit criteria will be applicable..... small motors doesn't protected with acb, they are protected by mccb. for for very small motors short circuit criteria is not applicable.
I have query about short circuit criteria. What about lower rating of motor like 0.37kw to 45kW? these Motors, dont have terminal box size which can accommodate cable size of 185sqmm, also its not economical to have such higher size of cable for small rating of motor and adopt power junction box for each such motor. In this case what will be criteria of short circuit? will it be system fault level or motor inrush current contribution?
These motors are having MCCB for which short circuit criteria is not required. Apart from that due to cable impedance the short circuit current is very nominal. So you need not to check. sC criteria is applicable for breaker operated feeders only.
Nice informative video sir !! Sir, can you please make an elaborative video on Ampacity of the cable. Also one more request... That can you provide us these calculations in an excel sheet as a tool, so as to generalized the sizing of thecable calculations, by just providing certain inputs parameters
hello sir..can you please let me know the specification of IE1 or IE2 type motor and the actual meaning of these. Another thing to know is in the voltage drop criteria where the multplication of 1.2 with 6xfull load curren. Are these coming from any standards. Thanks
Sir if I want to laying cable for 5.5 kw motor means ,what is the Short circuit current should I take ,if I take transformer short circuit means cable size will be increased..
good day to you sir, if you could make a video citing an example of a load with all the calculations of cable sizing, breaker sizing, bus bar and traffo sizing so we can get an over all view, in interviews they ask us to make an sld giving a load as an example and ask us to choose the breaker size and ratings for all equipments coming in it. well appreciated and keep up the good work
One of the best video i saw for cable sizing. Sir kindly make another video with some example.. Also how we can calculate short circuit for villas and mall where we have lot of pumps and AC machines. Here you took 50000 amps as a fault current and 0.2 sec time. The same will apply for homes and malls?? Thank you for the good explanation... Regards,
Very helpful,one doubt is there As per your calculation for short circuit current withstand with 2.5MVA trafo found 185sqmm, suppose I need to calculate cable for 30kw motor?? Why I will go above 185sqmm as motor FLC is approx 55A
sir,we have following input data for hydropower plants,installation capacity=5.5 Mw,Transmission voltage=33 KV,SC current=25 KA and fault withstand time for CB is 0.3 Sec ,i obtained following data 1)by using SC current method,area of Aluminium XLPE is 150 sq.mm and Cu XLPE is 120 sq mm,and from this data which cable i choose 3 core 120 sqmm or single core 120 sq mm?
Thank you so much, this was the video and explanation I was looking for. Thanks for such an amazing educational video. I have 2 doubts which I feel like to ask you, and it would be very kind if you will answer. 1st , after a lot of search I found a formula for voltage drop as per BSI 18th edition, also seen in several electricity regulations of GCC countries. The formula you mentioned in your video also can be derived from this. Voltage Drop (not in%) = =((Load current X length X (voltage drop per unit length per amp)) /(1000X no. Of runs) Now here the voltage drop per amp per unit length can also be written as (R Cos theta + j X Sin theta), so till here it's very clear, but in the video you mentioned a √3 which is obvious for 3phase load, but it's not used in the formula I mentioned, can you explain why??? 2) as per motor starting current 5 to 6 times of full load current, so for example let it be 10amp FLC and Staring current would be about 60 so, is that a cable of minimum 10mtr length shouldn't be choose 16sqmm cable instead a 4sqmm ?? Even though the starting current will persistent for 1 minute I belive?? Kindly give a appropriate reply. Thanks for such informatics videos.
Great work. God bless you. Also if possible please show one actual cable sizing for a 400v 15kw motor (just an example) with Cu/XLPE/SWA/PVC cable run in a cable tray
It was presented in a very understandable way. Thanks. Also I have a doubt. Is it required to take double the length of cable as the value of L, considering the return path ??
@@electricaltechnologyandind5335 please take a real example like a substation to a distribution transformer to a load For eg: from a 6.6kv swgr in a substation to a 6.6kV / 433v 1.5MVA transformer with 6% impedance at 50m and 50m distance from swgr and load side from the transformer respectively with a load consumption of 2200A during peak hours
consider 2.5 mva. you will get around 50 kA fault current. buy actual calculation you will get around 44-45kA, the switchgear busbars are rated for 50 ka for 1 sec, and the cable will be rated for 50 kA for 0.5 sec.
Thank you for such a wonderful video. I have one question how you have taken 50KA as short circuit of LT motor running at 415V. Can you please help me with this.
a transformer of rating 2.5 mva, with %z of 8.5% calculate the fault current. it will be around 45 ka, some between 40-50 ka. so for lt system 50 ka is taken.
The cables are always mentioned in their Voltage grade 1.1kv, 11kv, etc, now this voltage grade levelled weather based on the conductor's of the cable or the Insulation of the cable, overlapping the conductor?.
it is the insulation level. another thing is written if the cable is earthed grade or unearthed grade. so suppose a cable insulation is written as 1.9kV/3.3 kV that means the cable is suitable for installation in 3.3 kv with neutral solidly earthed
There are standard cross section of cables such as 2.5,4,6,10,16,25,35,50,70,95,120,150,185,240,300,400,630,800 &1000. They have their own current carrying capacity and resistance and reactance. Which can be found from catalogue. From there you have to finalise cable size as per the explanation
Sir I don't understand de rating term .According to Your Logic we increase Derating until its greater than Ampacity which is impossible because I multilpy Amps are Reduced 163.67×0.6= 98 A which is less ??
Suppose cable rated ampacity is 100 A, and on certain conditions the derating factor is 0.6. so possible loading on cable will be 60A. Now if you load current is 70 A you can not use that cable. Yu have to take higher size.
Thank you, Sir for sharing your valuable practical knowledge. I have a few requests at your descretion, Sir. Request1: Please,make a video on your education and carrier; how you gathered such great knowledge on Electrical Engg. It will inspire us further. Request2: Please share your email id or your website or your socials(fb, etc.) so that we could communicate better with you. Request3: Please let us know about some great books, websites, or papers, etc. which we could read to enhance our knowledge.
no, if you consider cable ampacity then it will be multiplied by derating factor. say a cable has rated current carrying capacity of 100 A and derating factor is 0.6 so its effective current carrying capacity shall be 60 A. that means you could only load the cable upto 60A
@@electricaltechnologyandind5335 alright, now if we calculate the full load current and it doesn't meet that 60 A ( for example 70 A) then we should increase either the no.of runs or cross sectional area right?
You can not calculate like that. You have to check manufacturer data. Search the internet for wire catalogue, you will get it. There you have to consider derating factor as o explained
It could be better if u could have explained how to consider the de-rating factor for different cable laying methods, instead directly considering 0.6. It is not covered about the short circuit current consideration for small rating of motor applications i.e as you mentioned in this video, for 50KA fault current minimum required conductor size is 185sqmm. what about small rating of motors i.e.10kw or 5KW
small motors are protected by mccb and due to its shorter operating time short circuit criteria is ignored. 0.6 is the safest case. explaining all the factors for arriving the derating factor would have make the video longer.
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clearer&better than the information I search online for an hour combined.
Thanks.....
you are first person who defined completely.
Very simple explanation cleared all my doubt regarding cable sizing calculation.
Thanks for sharing.
Wow ur way to teaching is great. 🙏
Thankyou sir make lectures in sequence so we can gain more. Thankyou again
Appreciate your Knowledge and effort to help needfuls.. 👌
Very useful information.thanks
How you selected 50kA for A=I √t/k
You have very good understanding of each and every factor....superb dedication...........I have been working in industry as an Engineer,I want read articles related to industrial technology can you please suggest me any source....
Thank you... May God bless you..
BEAUTIFULLY EXPLAINED.
Amazing briefing method.. Admires your's efforts boss.. 👌
Thank you for sharing this information. Keep up the good work brother!
For LT cable short circuit criteria is applicable?
As for small. Size of motor we can not use 185 sq. Mm cable..
of there is Circuit breaker short circuit criteria will be applicable..... small motors doesn't protected with acb, they are protected by mccb. for for very small motors short circuit criteria is not applicable.
You've explained very well appreciate it!
Really informative video🙏🙏🙏
Nice way of teaching
NICELY EXPLAINED
I have query about short circuit criteria. What about lower rating of motor like 0.37kw to 45kW? these Motors, dont have terminal box size which can accommodate cable size of 185sqmm, also its not economical to have such higher size of cable for small rating of motor and adopt power junction box for each such motor. In this case what will be criteria of short circuit? will it be system fault level or motor inrush current contribution?
These motors are having MCCB for which short circuit criteria is not required. Apart from that due to cable impedance the short circuit current is very nominal. So you need not to check. sC criteria is applicable for breaker operated feeders only.
Nice. Video sir...please make video on ups
Thank you, well explained
superb video... thanks for your hard work....
Very Nicely simplified briefing
can u tell how to get the K value from manufacturers website?
thank you for sharing this knowledge
Very nicely explained, Thanks!!
Nice informative video sir !!
Sir, can you please make an elaborative video on Ampacity of the cable. Also one more request... That can you provide us these calculations in an excel sheet as a tool, so as to generalized the sizing of thecable calculations, by just providing certain inputs parameters
hello sir..can you please let me know the specification of IE1 or IE2 type motor and the actual meaning of these. Another thing to know is in the voltage drop criteria where the multplication of 1.2 with 6xfull load curren. Are these coming from any standards. Thanks
Sir if I want to laying cable for 5.5 kw motor means ,what is the Short circuit current should I take ,if I take transformer short circuit means cable size will be increased..
In case of small motor which are protected by fuse or mccb you don't need to consider sc criteria. Perhaps i have mentioned
Hi sir,
How to find fault current in step no-1 for HT cable. If we don't have
good day to you sir, if you could make a video citing an example of a load with all the calculations of cable sizing, breaker sizing, bus bar and traffo sizing so we can get an over all view, in interviews they ask us to make an sld giving a load as an example and ask us to choose the breaker size and ratings for all equipments coming in it. well appreciated and keep up the good work
Ok i will do it. Thank you for your suggestion.
nice information.
Sir company's catalogue mention the X. The value of X of cable will be the same when number of cable run will more than one???
One of the best video i saw for cable sizing. Sir kindly make another video with some example..
Also how we can calculate short circuit for villas and mall where we have lot of pumps and AC machines. Here you took 50000 amps as a fault current and 0.2 sec time. The same will apply for homes and malls??
Thank you for the good explanation...
Regards,
Could you pls provide a video where "Number of cable runs" are explained? I could not understand this term
Great, thank you!!
sir, please explain ,what is reason to add 0.14sec as a margin, cannot we calculate with the same 0.11sec.
Very much useful video. Please upload a video for designing of 400/220/132/33kv substation.
Very helpful,one doubt is there
As per your calculation for short circuit current withstand with 2.5MVA trafo found 185sqmm, suppose I need to calculate cable for 30kw motor?? Why I will go above 185sqmm as motor FLC is approx 55A
I have the same question. For small rating of motor , it will be always difficult to terminate the 185 sq mm cable. Can you please explain
Perhaps i have mentioned that short circuit criteria is not applicable for mccb or fuse protected motor.
Why not applicable
Please share ht cable selection too
Super useful sir
Please make video to find out the cable aize for distribution transferomer,panel and power transformer
Very imp knowledge
sir,we have following input data for hydropower plants,installation capacity=5.5 Mw,Transmission voltage=33 KV,SC current=25 KA and fault withstand time for CB is 0.3 Sec ,i obtained following data 1)by using SC current method,area of Aluminium XLPE is 150 sq.mm and Cu XLPE is 120 sq mm,and from this data which cable i choose 3 core 120 sqmm or single core 120 sq mm?
Hi Sir,
What is the difference between LV and HV cable sizing?
Please make a video on HT Cable selection.
It will be more useful if you calculated for voltage drop criteria also.. anyways good and clear job❤
sir when motor rating is given in KW generally we dont consider efficiency but why had you considered? please explain bit confuse.
Kw is the rated output. But due to efficiency it will draw more power than the name plate kW
Great effort
Thank you for your good teaching
Thank you so much, this was the video and explanation I was looking for. Thanks for such an amazing educational video.
I have 2 doubts which I feel like to ask you, and it would be very kind if you will answer.
1st , after a lot of search I found a formula for voltage drop as per BSI 18th edition, also seen in several electricity regulations of GCC countries.
The formula you mentioned in your video also can be derived from this.
Voltage Drop (not in%) =
=((Load current X length X (voltage drop per unit length per amp)) /(1000X no. Of runs)
Now here the voltage drop per amp per unit length can also be written as (R Cos theta + j X Sin theta), so till here it's very clear, but in the video you mentioned a √3 which is obvious for 3phase load, but it's not used in the formula I mentioned, can you explain why???
2) as per motor starting current 5 to 6 times of full load current, so for example let it be 10amp FLC and Staring current would be about 60 so, is that a cable of minimum 10mtr length shouldn't be choose 16sqmm cable instead a 4sqmm ??
Even though the starting current will persistent for 1 minute I belive??
Kindly give a appropriate reply.
Thanks for such informatics videos.
Thank you for this video Also if possible please show one actual cable sizing for a 400v 1kw to 400Kw motor.
What if the load is only 20 ampere ?? Will you consider the Isc of the transformer for that??
Isc criteria to be considered for breakwr operated feeder only. In case current is only 20A there you will have mccb. So no need to consider
Excellent video...
Can you explain how to select motor earthing cable size???
Sir from which book I can more clearly learn cable size selection of cable
IEC 60364 PART 5
all are using this standard
165 Amp can be carried by 95 square mm cable, you suggest for minimum of 185 mm2 cable. HOW do you justify economically?
very clear thank you
What is 20% additional mergin as per IS rules?
Sir can u please explain about breaker operating time and about breaker..
Please Take an Example for Motor load & Electrical load like MCC panel. and then calculate the cable size.
What about tripping time for other types of loads? Say an ACB protected cable feeding a sub distribution panel,?
Great work. God bless you. Also if possible please show one actual cable sizing for a 400v 15kw motor (just an example) with Cu/XLPE/SWA/PVC cable run in a cable tray
good video,help me find out the size of cable that can accommodate 6kw load at distance of 100m.
Well done very nice plzzzz plzzz... Provide short circuit calculation and make vedio very confusion
Good one, appreciate for your clear understanding
how to get the formula book?
awasome
How to assume 50KA short ckt current can you explain deeply?
It was presented in a very understandable way. Thanks. Also I have a doubt. Is it required to take double the length of cable as the value of L, considering the return path ??
Yes.
Why the return path to be considered
Can you please tell us from where you got the value of "I" short circuit current?
that has just been an example.
@@electricaltechnologyandind5335 please take a real example like a substation to a distribution transformer to a load
For eg: from a 6.6kv swgr in a substation to a 6.6kV / 433v 1.5MVA transformer with 6% impedance at 50m and 50m distance from swgr and load side from the transformer respectively with a load consumption of 2200A during peak hours
consider 2.5 mva. you will get around 50 kA fault current. buy actual calculation you will get around 44-45kA, the switchgear busbars are rated for 50 ka for 1 sec, and the cable will be rated for 50 kA for 0.5 sec.
Where to find X and R values in V.D criteria?
In vendor cable catalog
Thank you for such a wonderful video. I have one question how you have taken 50KA as short circuit of LT motor running at 415V. Can you please help me with this.
a transformer of rating 2.5 mva, with %z of 8.5% calculate the fault current. it will be around 45 ka, some between 40-50 ka. so for lt system 50 ka is taken.
@@electricaltechnologyandind5335 so it has nothing to do with the motor rating. It is short circuit current rating of MCC
correct. fault current is source dependent. however the motor will contribute to the fault also but it shall be much less than trafo contribution
For motor how short circuit current will be find...
For 20 hp motor... What is the short circuit current???
You english is good
Nice one. Cable L will be in meter or Km in last voltage drop formula ?
meter. as far i could remember there has been a division by 1000
Great work... Kindly provide of substation design in 3d model
The cables are always mentioned in their Voltage grade 1.1kv, 11kv, etc, now this voltage grade levelled weather based on the conductor's of the cable or the Insulation of the cable, overlapping the conductor?.
it is the insulation level. another thing is written if the cable is earthed grade or unearthed grade. so suppose a cable insulation is written as 1.9kV/3.3 kV that means the cable is suitable for installation in 3.3 kv with neutral solidly earthed
Very good explanation
Thank you so much
very constructive idea
Sab mil gya value cable size kidr gya ?
Nice
Everything is Good explained but where is cable size in sqmm and how many core is there??
There are standard cross section of cables such as 2.5,4,6,10,16,25,35,50,70,95,120,150,185,240,300,400,630,800 &1000. They have their own current carrying capacity and resistance and reactance. Which can be found from catalogue. From there you have to finalise cable size as per the explanation
Sir very good information
Seqr sir., very informative.
Can you please introduce any catalog as an example??
Sorry. I can not show others content in my channel.
Sir I don't understand de rating term .According to Your Logic we increase Derating until its greater than Ampacity which is impossible because I multilpy Amps are Reduced 163.67×0.6= 98 A which is less ??
Suppose cable rated ampacity is 100 A, and on certain conditions the derating factor is 0.6. so possible loading on cable will be 60A. Now if you load current is 70 A you can not use that cable. Yu have to take higher size.
Sir provide information about cables charges
Number of run for 3-@ motor is 3...right..why have you assumed 2?
Thank you, Sir for sharing your valuable practical knowledge. I have a few requests at your descretion, Sir.
Request1: Please,make a video on your education and carrier; how you gathered such great knowledge on Electrical Engg. It will inspire us further.
Request2: Please share your email id or your website or your socials(fb, etc.) so that we could communicate better with you.
Request3: Please let us know about some great books, websites, or papers, etc. which we could read to enhance our knowledge.
Dear Sir,
This is very useful video for us. Kindly advice me , How to determine the reactance value of cu & Al cable in voltage drop calculation.
It is available in the catalogue. You have to take these data from cable catalogue
nice explanation sir...
Thanks
Nice nic e
So the Ampacity is 163.67/0.6 = 272.78 A in 13:41 ?
no, if you consider cable ampacity then it will be multiplied by derating factor. say a cable has rated current carrying capacity of 100 A and derating factor is 0.6 so its effective current carrying capacity shall be 60 A. that means you could only load the cable upto 60A
@@electricaltechnologyandind5335 alright, now if we calculate the full load current and it doesn't meet that 60 A ( for example 70 A) then we should increase either the no.of runs or cross sectional area right?
yes.... right.
@@electricaltechnologyandind5335 Thank you!
Short Circuit criteria are usually used for HT cable sizing, for LT cable Full load current is the criteria for sizing the cable size, pls comment.
Yes correct, but for breaker operated feeder this needs to be considered
Thank you very much
3hp submirsible motor single phase. I need cable size for aluminum. Distance from electric meter is 1000 to 1200 meter.
Don't think it will be possible. For 1.2 km managing the voltage drop it will be a huge cable size
How to fo you find such firmulaes
AVAILABLE IN CABLE CATALOGUE.
hey sir can you tell me where to find cos(titha) and sin(titha)
Theeta is the power factor angle of the load for which you are selecting the cable size.
Thank you dada
Sir, how can calculate 1.5 sq mm cable current capacity,, help me for calculation
You can not calculate like that. You have to check manufacturer data. Search the internet for wire catalogue, you will get it. There you have to consider derating factor as o explained
Please check Cross section formula … with respect to IEC …
It could be better if u could have explained how to consider the de-rating factor for different cable laying methods, instead directly considering 0.6.
It is not covered about the short circuit current consideration for small rating of motor applications i.e as you mentioned in this video, for 50KA fault current minimum required conductor size is 185sqmm. what about small rating of motors i.e.10kw or 5KW
small motors are protected by mccb and due to its shorter operating time short circuit criteria is ignored.
0.6 is the safest case. explaining all the factors for arriving the derating factor would have make the video longer.
thank you...