On Apr 8, 10:24�am, dpb wrote:
wrote:

...

...breakers are designed to become more sensitive as they age, ...

Have you any reference from a manufacturer that is a design criterion?

Don't say it isn't so, but I've never heard or seen it mentioned in any
literature which one would think would be so if were an actual design
feature.

I just did a search of the entire product brochure for the Square D QO
breaker series and there's no mention of "age" or "aging" or
"sensitivity" throughout.

--

hey when there trying to sell you something NEW they dont mention
againg might hurt sales.......

dont have a link of one even exists, but its true of all
breakers.........

a matter of liability, as it ages it has to change.

I repair office machines for a living that draw lots of current.

customer complains its tripping breaker, replace breaker trouble gone
provided circuit isnt overloaded.

some machines i service have breakers built in, and they fail
sensitive.

breakers trip from heat, my theory is contacts degrade a little, heat
and make things more sensitive.

I used to spend a couple days a month at westinghouse beaver, breaker
manufacturer. back before it was sold off, a fascinating place. nice
friendly folks, who told me more than i really wanted to know about
breakers. i tended to have lunch with the engineering group who were
the first to talk about more sensitive with age.......... had a bunch
of machines in engineering.