Tripping Breakers

[gbeichho]

Now that we've started a Federal Pioneer thread (under coloured wires), I have a question:

Should a breaker trip if a 125V circuit (15A) is fully shorted for a brief instant? I've seen two cases where the breaker does not flip and the tool shorting the wires had a hole burned through it. (bolt cutters)

George

[Wgoodrich]

Breakers trip due to two reasons. First reason is too many amps pulled through the hot and grounded leg [aka neutral wire]. That is overcurrent rating.

The second reason is called short circuit interupting rating. This will trip the breaker due to short circuit high current surges. This is called short circuit interupting rating. Problem is these breakers are designed to hold in a short circuit occurance for about two cycles of the a/c current. This will give time such as a motor high starting current loads to limit false tripping. When you cut that hot wire with the bolt cutter the current was broken before the breaker delayed the assigned time cycle delay for short circuit interrupting rating. A short circuit trip is rated normally in residential settings at 10 KVA [10,000].

Hope this helps

Wg

[gbeichho]

Makes sense. Thanks. We'll just have to be more careful with those bolt cutters! :)

I had to buy a new pair.