Simple Way to Calculate Short Circuit Current Using Point - to - Point Method

In this video, I will show you how to simply calculate short circuit current at any point using point-to-point method. This method is popularized by Cooper Bussman. I also made reference to IEEE Std-551 Violet Book for the motor contribution. This method is one of the methods used in short-circuit calculation.

[@kingszynrd5715]

Sir ganda po ng xplaination nyo sobrang smoth, salute po sayo... may kunting idadagdag lang po ako, dapat dun palang sa f1 & f2 meron ka ng motor contribution po.

[@justinlanielbaniqued2500]

Thank you Sir! Dami ko na pong napanuod abt short ciruit analysis diko ma gets yung iba pero yung inyo na gets ko agad hehe. Na lilito po kasi ako nung una paano kunin KAIC rating ng mga CB, salamat Sir sa learnings po! God Bless po.

[@RandyAmorchannel]

Salamat sir for watching my video

[@justinlanielbaniqued2500]

Sir may question po ako, yung 500kva 3phase transformer po ba single phase pole mounted transformer na naka banking lang po ba na consist of 167kva each rating ganon po? Parang sinum up lang Sir? Thank you po. ​@@RandyAmorchannel

[@emmanuellimjoco4709]

The best detailed computation ever watch. Galing mo Sir God bless and thanks for sharing.

[@RandyAmorchannel]

Salamat sir

[@raphaelcacanog73]

nakakatulong po ito maraming salamat po

[@RandyAmorchannel]

You're welcome sir

[@banjomirandilla3917]

Thank you sir clear and concise

[@RandyAmorchannel]

Thank you sir. God bless

[@Jepz_]

Engr
Ano gamit mo na software sa presentation 😁.. galing..

[@RandyAmorchannel]

Smath Solver sir, may video ako kung paano mag download at gamitin
ua-cam.com/play/PLfGtZkfoxIwyw55mf2kqRSNfz86rOLRuK.html

[@Jepz_]

Nakita ko Engr sa suggestion.. salamaat ng marami.

[@CharlieDelaCruz-ki7cx]

Sir
Saan nyo nakuha ang Table 4. C for Conductor?

[@erickmanangan4803]

Hello Engr. Nice video. Saan yan nilalagay A3 or A4 pag iaatached na at ipapasa for electrical permit? Thank you

[@RandyAmorchannel]

Kasama po yan sa analysis na ginagawa at pinipirmahan ng PEE. Normally separate sheet sa A4

[@gbgb8878]

It was nice video. Kindly give english subtitles.

[@RandyAmorchannel]

Thanks for the comment. I will try to put english subtitles to it.

[@minzenbae6899]

boss saan po naggaling yung 100 sa formula mo and saang book or page yung basis mo na Table 4.C?
thankyou po

[@ravenvillanueva7816]

sir pano po pag from center meter ang pag babasehan? pwede ba mag based sa 80percent ng kaic kung saan naka tap yung fault?

[@RandyAmorchannel]

Pag point-to-point method ang gamit mo kailangan mong mag simula sa source papunta sa point of fault kasi may factors na magdedepende sa fault current upstream ng fault point na gusto mong kunin.

[@RaelSeanLinda]

Constant PO ba Ang 100 sa pag calculate Ng multiplier?

[@jonasfuertes5895]

2nd is, di ba natin gagamitin yung actual voltage doon sa computation assuming na may voltage drop na pagdating doon sa Location ng Fault? Thanks

[@RandyAmorchannel]

Sir with regards to voltage used, ang voltage drop sa buong system ay limited to 3% from source to last point as per standards, so negligible na yung voltage drop. Kung gusto talaga nating gamitin yung actual voltage sa point of fault, pwede din naman pero mag calculate ka pa ng voltage at every point. Salamat sir and God bless.

[@kamotipstv6980]

sir anung program yang gamit mo?

[@jonasfuertes5895]

Assuming na running yung ckt at nagkaroon ng Fault sa Point 3, hind po ba magkakaroon ng contribution sa Fault yung motor loads? Thanks

[@RandyAmorchannel]

Yung point-to-point method, sabi ay kapag hindi significant yung motor contribution at pwede nang hindi isama. Sa dulo ng video pinakita ko yung fault currents at different points of the system with and without motor contribution. Salamat sir. God bless

[@DemetrioBautista-r9k]

Saan po Eng’r. Nanggaling yung Table 4 “C”?

[@eduardodangoy9730]

sir pwuede maka hingi ng smath solver "worksheet short-circuit calculation" for reference, thanks

[@RandyAmorchannel]

You may download the file from my Facebook Group
facebook.com/groups/usapangelektrikalph/files/files

[@marclestercarlos6619]

Kelangan ba iconvert to "feet" yung length ng cable?

[@RandyAmorchannel]

Yes po sir kailangan i-convert sa feet kasi yun po ang nasa formula

[@alvinnobitski2159]

Sir tanong ko lang po, kapag po ang fault point po ay nasa Main distribution Panel, ang Length (L) po ba na gagamitin sa formula ay from MDP to service point lang o from MDP to transformer?

[@RandyAmorchannel]

Consider mo yung length hanggang transformer kasi may contribution yung transformer sa fault current

[@arielgallego8803]

Sir, may video ka ba kung genset naman ang power source?

[@RandyAmorchannel]

wala pa sir, try ko gawan next time. Thanks

[@arielgallego8803]

@@RandyAmorchannel Salamat sir!

[@ouevv]

Sa value ng n, paano naging 2 sa pt 1? 3phase po diba so bale 3 wires? Medyo nakakalito lang.

[@RandyAmorchannel]

Yung n dun sir is number of parallel runs, in that case, n=2

[@jeffreymanalomanalo2682]

​@@RandyAmorchannelKunwari po 3 na acb galing sa hvsg to lvsg. So times 3? Tama po ba

[@RandyAmorchannel]

@@jeffreymanalomanalo2682 hindi po ganun sir. Yung number of parallel runs of cable po is kung ilang set ng three-phase cables and ginamit, for example kapag nakalagy sa single-line diagram na 2 - 3Cx100mm2 ibig sabihin 2 sets ng three-phase feeder so ang n=2

[@emmanuellimjoco4709]

Kung 1 set lang n value is 1.
Kung 3 sets ang n value is 3 di po ba?

[@jeffreymanalomanalo2682]

Sir sana po naituro mo din yun breaker na gagamitin para sa na compute na fault

[@RandyAmorchannel]

sir pagdating sa breaker na gagamitin base sa na calculate ng fault current, ang rule lang naman dun ay kunin mo yung breaker na may kAIC rating na equal or mas mataas sa calculated fault current.

[@jeffreymanalomanalo2682]

@@RandyAmorchannel thanks

[@eap0226]

Paano po kunin yong n, number of parallel rods?

[@RandyAmorchannel]

Sir sa design po yun makikita normally naka indicate sa single-line diagram

[@christophermillan6310]

good day po, constant po ba ang percentage ng impedance, or naka depende pomsa size ng transformer?at kung oo po,san po pwede macheck ang mga impedances na to?

[@RandyAmorchannel]

Yung impedance ng transformer varies depende sa capacity at sa manufacturer din. Makikita naten ang % impedance ng transformer sa nameplate. Salamat sir question mo sir. God bless

[@marvin082500]

@@RandyAmorchannel Sir kung walang nakaindicate na impedance sa nameplate, ano ang gagamitin na impedance?

[@RandyAmorchannel]

@@marvin082500 standard nameplate ng transformer shall always include impedance. Pero kung di available for example eh nabura na or nawala yung nameplate, etc at wala kang sources ng information tungkol sa impedance, pwede kang mag refer sa IEEE std 142 or yung Gray Book. May table dun na Approximate Impedance Values.

[@marvin082500]

Thank you Sir @@RandyAmorchannel

[@rommelbondoc1121]

Engr anong program/app yun gamit mo na auto nagcompute after mo magtype?

[@RandyAmorchannel]

Smath Studio sir. May tutorials din ako tungkol jan
ua-cam.com/play/PLfGtZkfoxIwyw55mf2kqRSNfz86rOLRuK.html

[@rommelbondoc1121]

@@RandyAmorchannel salamat

[@bloomberg4865]

Bkt s pag compute mo ng isc3 hindi mo naconsider ung current contribution ng motor during fault condition. Meron dn yan contribution.

[@anniehofer4151]

Sir, yung 500KVA sa simula san po sya kinukuha? Gumagawa kasi kami project sa residential house and di ko sure if sa schedule of loads ko ba kukunin yang KVA

[@RandyAmorchannel]

Sa utility po yun sir, kVA rating ng utility transformer

[@cas49713]

Good day sir, accepted na ba ang poin-to-point method ng Bussman sa PEE exam or sa detail engineering? Thank you in advance.

[@RandyAmorchannel]

Ang alam ko PU method ang accepted ng OBO for permit. Dapat na siguro mag update ng OBO sa acceptable method of calculation ng SC to include other methods. Pero magagamit mo tong methid na to for quick calculation para sa KAIC rating ng equipment

[@pochitaiitft]

Sir anong software ginagamit nyo

[@RandyAmorchannel]

Gamit ko Smath Studio

[@Botchukoy]

sir, anung gamit mong app sa presentation?

[@RandyAmorchannel]

Smath Solver (formerly known as Smath Studio) sir gamit ko jan. Free alrernative to Mathcad

[@Dragon26-Tiger31]

sa calculation ng M1, 100 divide by Z times 0.9, san nangaling yung 100?

[@RandyAmorchannel]

constant po yun sa formula sir.

[@Dragon26-Tiger31]

ano ang formula?@@RandyAmorchannel

[@RandyAmorchannel]

@@Dragon26-Tiger31 sir nasa video po ang formula M=100/(%z x 0.9)

[@leovincalubag479]

anong C value and dapat gamitin pag Single Phase.

[@ImmortalShiro]

Same lang din. Naka dipende naman po kasi yung C values mainly sa wire size, then kung magnetic or nonmagnetic yung conduit, tsaka yung voltage.

[@RandyAmorchannel]

Walang separate value for single phase. Magkaiba lang ng value for single conductors and multi-conductor cables or kung busway

[@jeffreymanalomanalo2682]

Hello sir. Saan po nakuha Yun 100

[@RandyAmorchannel]

Yung 100 sir ay kasama sa formula yun

[@dhardstv9818]

boss panu mo ginawa sa diagram?panu ininsert

[@RandyAmorchannel]

Ginawa ko muna boss sa powerpoint then copy & paste

[@OP-OP999]

Hello Sir. Blurry po ang given. Kindly provide clearer video. 🙏🙏🙏

[@RandyAmorchannel]

Malinaw naman po yung video.

[@OP-OP999]

@@RandyAmorchannel Hello po Sir Randy. Blurry sa cellphone ko sir. But clear sa laptop. Maraming salamat po sir.

[@OP-OP999]

@@RandyAmorchannel Hello Sir Randy, tanong ko lng po kasi nalilitu po ako. yung impedance po ng transformer is 5%. Yung tanong ko is M1=100/(5)(0.9), since 5% po yan sir hindi po ba dapat 0.05 ang gagamitin natin Sir? magiging M1=100/(0.05)(0.9)?

[@RandyAmorchannel]

@@OP-OP999 kung ano po yung naka indicate na %Z ayun po yung gagamitin hindi na po gagawing decimal

[@OP-OP999]

@@RandyAmorchannel got it po sir. Maraming salamat po at binigyan niyo po ako nang kalinawagan.

[@incoyjoshuagabriell.4184]

san po nangaling yung %z=5 thanks po

[@RandyAmorchannel]

Sir yung 5% impedance po ay given sa problem, pero sa actual na calculation kukunin nyo po ang impedance sa nameplate ng transformer. Salamat po sa panonood sa video. God Bless.