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Do new breakers trip faster?

6K views 18 replies 12 participants last post by  Circuit Tracer 
#1 ·
Do new breakers (manufactured/installed in the last 10 years) short circuit trip faster than older ones?

In the last couple months, I have experienced a dead short on a 20A 120V circuit that barely made a spark. I was certain that it was a GFCI circuit because I saw no sign of arcing.

I used to be afraid to dead short a non GFCI circuit (to identify it :jester:) because the arc freaked me out. In the old days, it was like a mini welder for a while until it tripped. Sometimes it would take more than one attempt.

I was just wondering if they changed the specs or design to recognize a short and trip faster.
 
#15 · (Edited)
Even though it's over thirty years old, it's an excellent article meadow, thanks for sharing. :thumbsup:

For me, it drives home the myths in those days and the misconceptions blindly followed by experienced professionals.

Also a very strong hint as to the development of AFCI protection. I think I will change my mind and support AFCI protection throughout the home. :eek: :thumbup:

Once again, I digress. Sorry.

Borgi
 
#4 ·
It all depends on the short itself, high resistance ones are going to be slower to trip, bolted solid ones are going to go thru the bell shaped curve faster and trip it better. Also the fault current available at each location will be different, so that explains why the fireworks are different sometimes. In a busy office building a short circuit can boom an electrician right into the burn unit or grave, so they are not something to mess around with.
 
#8 ·
I've seen some serious FPE lightning bolts....:no:

But now i'm curious, because i suspect the potential are older subpanel(s) fed via a Square D , or other magnetically lower main tripping before the branch circuits do....:(

~CS~
 
#12 ·
I used to be afraid to dead short a non GFCI circuit (to identify it :jester:) because the arc freaked me out. In the old days, it was like a mini welder for a while until it tripped. Sometimes it would take more than one attempt.
I watched a guy turn a 6" long conductor (in a metal box) into a 2" long conductor before I got him to quit trying to trip the breaker by flashing the conductor to the box. Circa 1975 in a remodel job in downtown Norfolk. This was the same guy that did not understand you could not put two hot conductors from the same phase (different breakers) with the same neutral.
 
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