ano sanhi ng pagsabog ng circuit breaker???

[basteng]

considering na bago ilabas sa planta ang controller dumaan na ito sa quality at testing. ngayon dumating yung panahon ng testing and commissioning, pag-on ng breaker bigla itong sumabog na sanhi ng pagkasunog ng kamay ng kasama ko. by the  way yung controller ay para sa hvac system. tulungan nyo akong bigyan liwanag ang mga bagay na ito.

[DigitalMind]

ang design nang circuit breaker in the first place is for SAFETY.
sure naman kyo sir na tama ang pagkakalagay nang circuit breaker (i'm sure ok yung pagkakalagay)
pero sa tagal ko din nag i-install nang circuit breaker/wiring. kahit i trip ko nang i trip di posible na sumabog.
it's really rare na mag fault yun... let's wait for some masters sa electrical installation.

[jacks]

Mas maganda kung ilagay mo kung anong klaseng circuit breaker pati size and rating. At gaano kalaki ang load.

Dapat natest ang breaker out of the system bago ilagay.Continuity ng pole para sa isolation ng bawat phase. At natest rin ang supply wire run ng load at ng load mismo. Pati yung play ng breaker kung matetest.

Maaaring sa pakalagay ng wire at cb nagkaproblema, heavy short circuit ang pwedeng magcause nito.

[ahlburuto]

Wala pa akong nakitang sumabog na CB ah, Kahit yung tipong shorted yung secondary at iswitch On mo yung CB eh trip agad. Not unless malalaking ampacity na yung CB.

Merong CB nga pala na design sa Line Neutral system. Eto yung CB na ang me protection eh yung Line side lang at yung neatral eh wala (act as a switch lang). This case once na nagkabaligtad ang supply (Yung hot eh napunta sa neutral at yung neutral eh napunta sa hot) mo tapos faulty or grounded yung secondary eh pihadong Kaboom ang CB mo. Kaya tignana mabuti ang design ng CB.

[franzschluter]

Madaming reasons pwede mangyari un.. And by what term do we mean sabog? "BOOM?" "SMOKE?" "SPARK?" "LOUD CLICK?"

Proper way of handling CB breakers:

Bago I on... Check dapat muna sa load side kung may shorts. Make sure din na walang appliances or machinery na naka "ON". This way sigurado tayo na walang malalaking transient current makaka daloy.

Bago install try flipping ung switch na hindi muna naka kabit kung may sayad or kung hindi for safety purposes lang. Check its terminals for shorts when flipping

After installing and flipping ung switch and makita everything is okay. Kuha ka voltmeter and check from input terminal to output terminal kung ilan ang voltage drop. Kung nasa mV lang usapan then this is okay. Kung pataas naman ng 5V eh palitan mo na ung CB. Higher voltage drop means not so good contacts at pwede mag heat up ung CB. Or kung matipid.. Tangaling muna ung CB and clean the contacts with a fine sand paper.

Reasons bakit sumabog:

1. Short circuit or a very very big load na hindi rated para sa CB na un. Even in this case dapat mag break/trip ung CB.
2. Low Quality. Pag flip ng CB nag kalas ung springs sa loob then ung terminals napadikit sa hindi dapat.. (Very unlikely pero hindi impossible)

[brian_po]

faulty ang mechanical ng breaker. this is the only cuase kung bakit sya sasabog..
naka experience na ako nito...

nakakita ka na ba ng Buzz Bar na nadikitan ng malaking screw driver? "yung nalaglagan ng screw driver" may malakas na pagsabog na mangyayari at mapapansin mo na yung Buzz bar mismo halos maputol na kahit na abot 1in width at 5mm depth ganun kalakas yun halos tunawin yung copper na buzz bar..

ganun din nangyayari sa breaker na yun. faulty yun mechanical nya.. mas mahirap mangyari ito sa MCB. pero kung sa branch circuit lng pwede ba masuportahan ng MCB..

i-compare mo nalang sa buzz bar at ang breaker mo.. ilang amp lang ang kaya nyan.
pero yung buzz bar na kaya mag handle ng almost 500amp pataas eh tinutunaw pa ng short circuit basta direkta sa line no breaker/fuse before the line.. isipin mo lng MCB na direct na sa supply ng distribution transformer..

[brian_po]

ito- i compare mo nalang sa copper na nakalagay sa breaker mo..
itong buz bar na yan halos maputol yan.. naalala ko pa dati sa planta ako ng work.
pinasok ng pusa ang panel board.. Buzz bar sya na diretso magbigay ng supply sa MCB..
ang pusa di na nakilala.. kalat ang laman sa EE room.. tapos ang buzz bar halos maputol..
ito kapal ng buzz bar 

[akosiikem]

Kung mapapatunayan nyo naman na factory defect ung breaker and tama yung installation base sa manuals, ang alam ko may habol kayo nyan.
Nangyari na yan sa planta namin pero hindi breaker involve. Commissioning ng MTS, Pag on umusok yung buong panel. Upon investigation,
nagliyab yung over current relay. Sabi ng contractor factory defect yung OCR(Mitsubishi brand)na nilagay nila. Sabi ng boss namin nagbayad daw ang mitsubishi.

[brian_po]

tinggin ko factory defect tlga ang breaker.. pwede sila mag file ng report sa company.

[franzschluter]

Indeed there is a possibility for the buzz bar to melt when shorted by a screw driver and even 100A is enough to do the job, copper rod for welding is a perfect example how fast it would melt. But I find it very impossible to happen unless there is no cover on the CB? Consider also the plastic moldings on it. How should it be possible to have a perfect contact between two lines? And how would it be possible to have a screw driver inside the CB in the first place? There are no contacts inside the CB that would allow for a screw driver to have a contact between the two lines 

Here are some pics for example...






Possible things could also have happened.
1. Somebody placed a screwdriver on top and during switching it fell down. Explosion happens.
2. The one who flicked the switch was barefooted and the CB is grounded. (I've seen carpenters naka tsinelas magtrabaho din tapos papasok ng building aalisin pa nila ung tsinelas)
3. Wet? Our breaker at home once got really wet. It made a few sparks but that was it. It didn't explode. Plus water is a bad conductor. But still conducts.

Between these two possibilities and the possibility you've mentioned isn't due to the CB's fault but to the one who installed it. BTW how should a cat find its way inside a panel? Normally panels are usually enclosed.

But the best way to know parin is when they open it up para wala nang guess work. Have it investigated and make pictures. Then sue whoever who has to be sued. Mahirap kase magbintang ng tao in charge at mas mahirap din mag bintang ng faulty CB.  Kung kakasuhan I think somebody has to do the investigating para maging evidence ung CB na un....

[brian_po]

yung buzz bar na sinasabi ko yun kinakabitan ng mga MCB depende sa demand.


parang hindi pa ako nakakakita ng sinasabi mong buzz bar na may plastic cover ah 
puro copper rod lang yun na madaming turnilyo eh. tapos kada turnilyo dun kakabit ang MCB.
may cover sya pero sa panel lang hindi sa buzz bar mismo.. 
kasyang kasya ang screw driver dyan.. teka lang example ko lang yun eh.
example para malaman nya kung gaano kalakas sasabog ang line pag na short at walang CB
ganun din kasi mangyayari sa CB na shorted or welded ang contact

[franzschluter]

Plastic molding... I am referring to the plastic of the Circuit breaker as this was the question from the poster. The one colored black inside the the CB there are plastic moldings that prevent contact in between terminals.

Besides if there really was a screw driver inside then it is indeed the persons fault who placed the screw driver inside and it would not be because it is faulty. I am understanding you mean MCB (Mechanical Circuit Breaker). Maybe you are referring to something else perhaps.

And about an example kung gaano kalakas. I mentioned you there to be correct. Malakas talaga ung sabog dun. No doubt about it.

But is impossible to happen since connecting the phases or terminals together is very unlikely to happen and hard to do. As some people mentioned if the load is high, possible mag ispark din un. But not explode as it should trip.

If the contact is welded naman, iinit un or cannot shut off if the load is too great and eventually it might or could burn. Kung welded un. But we talking about a bnew CB that has clean and new contacts. It cannot weld. Welding happens due to poor contact terminals when the contacts begin to corrode.

[brian_po]

bakit pinipilit mo yun sa screw driver example lang yun eh.
ang hirap naman ng iniintindi sa iintindihin.

out na ako d2 s thread na to.
MCB pala, Main Circuit Breaker 

[rage3657]

shorted. ... kaya after wiring installation make sure linisin and inspect mabuti ang panel kasi during the works maaring may nahulog na bolts, washers or metal burrs from drilling from making holes, cut out.. na maaaring pag mulan ng shorts pag power up.

[miGs]

circuit breaker is intended to operate on SHORT CIRCUIT or faults. Just make sure that the kilo-Ampere Interrupting Capacity (kAIC) of the breaker is equal or greater than the maximum available fault at the point of connection of the breaker.

[valtomotive]

nagtataka ako sa circuit breaker dito sa shop namin nag kabit ako ng welding machine at 3 phase motor cement mixer sa 50 amp breaker inde ko napansin na maliit pala yung wire na papunta sa main line nag sabay gamit ang mixer at welding nasunog yung mga wire umispark inde nag trip yung mga breaker

[iyo karpo]

considering na bago ilabas sa planta ang controller dumaan na ito sa quality at testing. ngayon dumating yung panahon ng testing and commissioning, pag-on ng breaker bigla itong sumabog na sanhi ng pagkasunog ng kamay ng kasama ko. by the  way yung controller ay para sa hvac system. tulungan nyo akong bigyan liwanag ang mga bagay na ito.

mababa ang KAIC ng breaker na to kaya sumabog.

[sundyhips]

mao ba

[iyo karpo]

mao ba

barato ang breaker kung gamay ang KAIC.

[olsen_myk]

hi guys, i do have situation na na-deform ung casing ng circuit breaker nmen.. what are possible implication of this?? mei history ng tulo sa breaker pero operation prin sha? i mean nggmit pa rin, pero still ung risk ng deforms are there. hope to help me on this.