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First recorded activity by BoatBanter: Mar 2007
Posts: 37
Default Ping Larry - Circuit Breakers


"Peter Hendra" wrote in message
...
| I suppose that I should have been more specific. What I intended to
| convey was that I already have a heavy duty switch that cuts off the
| power to the anchor circuit. I did not mean that I would use it as an
| "up" or "down" switch. I was wondering whether I could use the breaker
| as an on/off switch to control the power from the batteries
|
| Thanks
| Peter
|
| On Mon, 16 Apr 2007 10:21:48 -0400, Chuck
| wrote:
|
| 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...4TommieSubmitt

ed.pdf
|
| http://history.nasa.gov/alsj/alsj-CBsVsSwitches.html
| Using Circuit Breakers as Switches
|
| Good luck!
|
| Chuck
|
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On my previous boat I've used one of these as my anchor main switch to
isolate from the batteries for 10 years without a problem. Of course it is
not used to switch the high amps load for the anchor winch. It is used as an
isolation switch only. A load switch and an isolation switch are 2 different
things. Having said that, all the switches on the distribution/ switchboard
were also combined switches/circuit brakers. I never had a problem using
them for switching small loads (e.g. to turn the cabin lighting on or off).
Wout