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Chuck Chuck is offline
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First recorded activity by BoatBanter: Apr 2007
Posts: 72
Default Ping Larry - Circuit Breakers

Matt Colie wrote:
Peter,

You got one answer with no explanation.

A circuit breaker is a switch. - Period (Some used in vehicles are self
-resetting, they are still switches but with no manual control.)

The features note means that it is designed to be used as a manually
controlled disconnect under load. The manufacturer believes this device
can do that safely.

This is largely a moot point in your case. The windless switches are
the devices you use to control the actual motor. You will not be doing
that if your arrangement is at all like any I've ever seen.

The only time you will use this as a switch is if you choose to
disconnect the feed to the actual switching circuit for the windless.

Circuit breakers used to be certified to interrupt the current at rated
load or greater only five times, and came with instructions to replace
them if they had been tripped or manually operated more than twice.

Then along came the category called Switch Duty Breakers (SWB). These
are certified to pass UL, NFPA and NMEA requirements on matter how many
times they are cycled. Most still come with a note to replace if they
are opened by overcurrent - this is because the contact might be damaged.

I am paranoid (I find it serves me well) so I put Switch Duty Breakers
in my shop wiring to control the two banks of lights. Though I had
every intention of putting a pair of 3-way switches by the two doors, I
have been turning the lights on out there at least once a day for
fifteen years. When I tested them last (not something a normal person
can do), both were still within specification. I will put in the above
mentioned switches someday - if I don't kill my self getting to the
breaker box in the dark before that.

Matt Colie
Yachtman's Technical Support
www.yachtek.com



Peter Hendra wrote:
Larry,
I have jusy puchased a "Blue Seal" brand - "Bussman series High Amp
Circuit Breaker" - 125 Amps; for my anchor winch circuit.

Stated on the packaging under "featuires" is "combines switching and
circuit breaker function into one unit"

Question: Is it good practice to use it as a switch?

cheers
Peter Hendra



Why not ask Blue Sea how many switch
operations you can expect their breaker
to perform with your anchor winch load?
Then you'll have an answer you can rely
on. It goes without saying that you'll
be installing the breaker in what is
euphemistically considered a "damp
environment". Be sure to mention that to
Blue Sea, so as to discourage
presentation of results from laboratory
testing in a pristine environment.

As a general rule, combining functions
tends to result in compromises to one or
more of the functions. The links below
examine this issue for breakers as
switches, but not specifically for Blue
Sea products.

You obviously are aware of that and are
questioning Blue Sea's advertising.
You're just asking the wrong people: not
one of us on this group has probably
developed credible statistical data on
Blue Sea breaker failure rates as a
function of number of cycles of
operation. Their web site seems mute on
the subject also. Some breakers have
been designed to perform well as
switches and manufacturers often quote
performance data to support their claims.

http://www.etk.ee.kth.se/personal/li...eSubmitted.pdf

http://history.nasa.gov/alsj/alsj-CBsVsSwitches.html
Using Circuit Breakers as Switches

Good luck!

Chuck

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