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Can arc flash happen in 150 amp main breaker?

Can arc flash happen in 150 amp main breaker?

Can arc flash happen in 150 amp main breaker?

(OP)
In a household main breaker with 150 amp panel.
Can  an arc flash happen?

 

RE: Can arc flash happen in 150 amp main breaker?

Possible but not too likely.  Testing has shown an arc can be sustained at 240 V under certain conditions (enclosure size, gap, available fault current).  Typical residential service served from a 15 kVA or 25 kVA transformer probably does not have enough available fault current to sustain an arc unless you are having a really bad day.  

 

RE: Can arc flash happen in 150 amp main breaker?

I didn't get a sustained arc as I had a screw fall from ?? across a 240V 200A house panel's bus bars. There was a blinding fireball about 6 inches in diameter that lasted perhaps 100ms.  The 200A breaker did trip at this point.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Can arc flash happen in 150 amp main breaker?

You were having a bad day?  

I don't know Keith...  Normally, once whatever initiated the arc is vaporized, the arc goes away at 240 V.  Not always, though.  Even if the arc is sustained, the heat energy is normally not as high as for a 480 V fault.   But you are in a class by yourself.  looking around



 

RE: Can arc flash happen in 150 amp main breaker?

He asked only if an arc-flash can happen -- seems to me the answer would be "yes", even though the arc might not be sustained.....   

RE: Can arc flash happen in 150 amp main breaker?

Well it was a bad day.. One I couldn't see much of after that event.
 

Keith Cress
kcress - http://www.flaminsystems.com

RE: Can arc flash happen in 150 amp main breaker?

An arcflash can happen and even sustained as what dpc said (bad day)! Welder units have open circuit voltage of around 70 VAC and needs to maintain an arc to do its job!
They keys are:"gap", availability of the conductor(electrode) maintaining that "gap" and the source. If the gap widens fast (conductors melting fast), then the arc dies out quickly.
The truth is, I never had a chance to observe it 'cuz I closed my eyes when I had my bad day once!

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