[RE-wrenches] AC breakers used in DC applications

[William Miller]

Kurt

Fascinating story and valuable information.  This is the kind of real world 
experience we need to draw on.  Reality can change quickly under extreme 
conditions and one's education is not complete without this understanding.

Thanks for this post.

William Miller

PS:  You are fortunate your client had a proper fire suppression system.  I 
doubt many of us can count on that to minimize damage.

Wm



At 03:13 PM 5/16/2010, you wrote:
>Voltage is not the issue here, it is current, and battery fault currents 
>can be staggering - far more than one would ever encounter in a typical AC 
>system fed from a distribution transformer.  I have seen a 200A Class T 
>fail to act on an 48V inverter fault which resulted in welding the metal 
>tabs of the fuse holder (which had been greased with copper-laden Penetrox 
>E) to their sockets.  That indicates a fault current well north of 200,000 
>amps, quite possibly sseveral times that.   A fire ensued, which triggered 
>the gas protection system and fortunately resulted in almost no peripheral 
>damage.  It did cost about $10k to recharge and recertify the Inergen 
>system.  The inverter manufacturer was quite cagey on warranty replacement 
>until they saw the photos - at which point a replacement miraculously 
>arrived by overnight air.
>
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