# Help...Bussman ShortStop 24VDC 40A Circuit Breaker



## JAFO (Aug 2, 2008)

Hey peoples,

I have a dumb question...

Say I have a Bussman ShortStop 24VDC 40A Circuit Breaker, and if I use this
with 12VDC input, does this mean it will break at 80A?


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## rfengineers (Jun 2, 2008)

JAFO said:


> Hey peoples,
> 
> I have a dumb question...
> 
> ...


If it is working properly it will trip at or slightly above 40A.

The Voltage rating is a maximum and is related to dielectric strength and the tendency to arc.

Not a dumb question at all.


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## JAFO (Aug 2, 2008)

Thanks for the response...I "ass"umed it would double the amps at half the applied voltage, don't know where i got that... who knows


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## TX_Dj (Jul 25, 2008)

It's a common confusion, JAFO. It arises from the conversion equations which tell us that if you are running a load at 24v that consumes 40a, it would require 80a at 12v to do the same work.

That equation all boils down to watts... you're converting watts to a specific volt/amps.

As far as breakers go, it's all about the amps. An ampere is the measure of electrons flowing thru a conductor regardless of voltage and watts. I.E. if I had a fuse rated for 10a @ 250v, I could still use that at 12v, and it would still pop somewhere around 10a @ 12v. Like rfengineers said, the voltage rating on a breaker/fuse is just the max voltage it's rated for. Stay within that and within the amp rating of the item, and it will perform as designed (more or less).


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