Gunner Asch wrote:

On Wed, 26 Oct 2011 21:52:34 -0700, jk wrote:

"Michael A. Terrell" wrote:



Manufacturing tolerance will decide which breaker goes first....


Sure, with Chinese breakers.

That's why I sugessted adding the external dual pole breaker with
common trip.


With ANYBODY's breakers. Especially cheap thermal magnetic ones.

The tolerance bands are typically +/- 10%.
And that is assuming they work at all.

jk

I should stick in a bit of information here about breakers. One of the
common types readily avaible are Murrey breakers.

They suck badly. Ive had to replace 22 of them this year in an
installation thats only 3 yrs old.

Burned contacts at the base of the breaker, along with breakers that
trip far far too easily.

After this year..Im going with SquareD in all my installs. Murrey was
cheaper..but the amortized costs are more, both in hardware and down
time.


Murray was interchangable with a lot of other brands.

American Switch
Arrow-Hart Bryant
Crouse Hinds
Cutler-Hammer
Electri-Center
Frank Adams
General Electric
General Switch
Gould
GTE Sylvania
Montgomery Ward
Murray
Siemens
Westinghouse/Bryant

Sears had a series that fit at one time, as well.


A lot of breakers and panels are shipped with little or no ontact
lubricant, which causes early failures. Some 'electricians' wipe it off
the buss bars, causing their own problems.

http://ecatalog.squared.com/pubs/Cir...0600DB0109.pdf

--
You can't have a sense of humor, if you have no sense.