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  1. #1
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    Default Circuit breaker Life Expectancy / Useful Life

    In general a circuit breaker has no Life Expectancy or Useful Life.

    A forum member made a statement in another thread that raised a question that I never gave any thought to in the past.:


    “Breakers have a life expectancy like anything else and when they get old like most things they break down and are less likely to work as designed.”

    I have operated under the understanding that an electrical circuit breaker would operate under normal use indefinitely. They work until they don’t. Manufactures offer a Lifetime Warranty based on a manufacture defects on most residential breakers. Useful Life or Life Expectancy are not terms I have found in any of the manufactures literature nor in any testing reports. There are limits set for quality testing of the products but are not reflected in the concept of Useful Life.


    My posting is informative in nature for the many members and guests to the forum.



    Should anyone have information to the contrary, please post the links or sources that can be referenced by others.

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  2. #2
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    after two trips at full available fault current they are supposed to be replaced

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  3. #3
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    Quote Originally Posted by Garry Sorrells View Post
    In general a circuit breaker has no Life Expectancy or Useful Life.

    A forum member made a statement in another thread that raised a question that I never gave any thought to in the past.:


    “Breakers have a life expectancy like anything else and when they get old like most things they break down and are less likely to work as designed.”

    I have operated under the understanding that an electrical circuit breaker would operate under normal use indefinitely. They work until they don’t. Manufactures offer a Lifetime Warranty based on a manufacture defects on most residential breakers. Useful Life or Life Expectancy are not terms I have found in any of the manufactures literature nor in any testing reports. There are limits set for quality testing of the products but are not reflected in the concept of Useful Life.


    My posting is informative in nature for the many members and guests to the forum.



    Should anyone have information to the contrary, please post the links or sources that can be referenced by others.
    Not about to get in to a debate about your 'understanding' nor your 'opinions' on this subject.

    I disagree with your assertions, as do multiple generations of changes to the various standards, designs, features, materials, mechanisms, etc. which have covered and been used to produce these devices over the many decades.

    Although authored for and geared for the other-than-strictly-residential and other-than-self-employed or other-than DIY application/reader, here is just one of hundreds of papers. PLEASE READ the FIRST ATTACHED (then review various (older, legacy, and more current, manufacturer's inserts, instructions, etc. regarding maintenance, inspection, etc. for MCCBs).

    UL Engineer Dini, UL, CPSC, and others engaged in a multi-year project regarding residential vintage electrical, paper too large to upload here, have linked to it several times in the past. The actual applicable standards have even changed in some cases (ex. what used to cover HACR breakers, second attachment, etc.).

    The attached should 'get you started' in your quest for knowledge and 'understanding' and formulating conclusions or opinions on facts. I further suggest you find a resource to the actual standards themselves and read the legacy (superceded, former) editions of same, as well as review some legacy data & instructions. Warning, you'll find ownership and corporate structure has changed (in some cases multiple times) regarding manufacturers & who owns branded names multiple degrees of separation for multiple substantial changes for what is obsolete regarding design, function, safety, and reliability.



    Bottom line, following an exposure event, time, exposure, conditions, duty cycles, failure to inspect, maintain, what vintage - type-design-materials style, etc. it DEPENDS on far too much to make any such universal all-applicable statement. The likelihood of reliable, dependable performance in any AND EVERY parameter is unknown without specific examinations and testing. As the first attachment discusses, combined with the anecdotal observations most every HI has experience with, and multiple surveys regarding HO's & occupants relative to investigations/inspections/maintenance/visits to a CB panel, the "odds" are against your 'understanding' IME (forensic post injury, death, fire examinations, as well as investigations, full bench testing, etc. un-suspected, non-event, removed equipment, and review of work of others - published & unpublished) especially regarding obsolete equipment, pre-1970 equipment, and pre-mid 1980s manufactured equipment, and even equipment of more recent design, tested and testing design standards, not just limited to functionality of safe switching during AIC exposure under stated limit.

    Last edited by H.G. Watson, Sr.; 08-27-2013 at 01:13 PM. Reason: forgot to attach documents.

  4. #4
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    So we are in agreement that there is no way to state that there is a general Life Expectancy or Usefull Life of a circuit breaker. Therefore it is not appropriate to state "Breakers have a life expectancy like anything else..." .


  5. #5
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    I agree with Garry
    There is not a stated life expectancy for (most) circuit breakers
    The failure rate of circuit breakers is not determined by age of the breaker.


    This is from Schneider Electric


    Wants MTBF (Mean Time Between Failure) data for circuit breakers.


    These measures are not designed for electro-mechanical devices and do not provide meaningful data. Circuit breaker life is more a function of number of operations, overloads, short-circuits, operating environment, etc. We have no MTBF numbers to offer.

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    Last edited by Rick Cantrell; 08-29-2013 at 05:49 AM.
    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  6. #6
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    And no maintenance requirements were evaluated or recommended for residential application. Probably because of the electromagnetic trip mechanism compared to the probability of a commercial/industrial CB having a more complex trip mechanism. As we all know any requirements for residential devices is not enforceable. IE the given life expectancy in a residential application is essentially until "failure or removal"..

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  7. #7
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    Rick,
    You say "most" , I would like to find a source that states "Life Expectancy" or "Useful life".
    What I find is test data on failure rate. Percentages in relation to events.

    Manufactures offer (residential) Lifetime Warranty against defects. Which is not translated to any term of "Useful Life".

    There is equipment that has been deemed by different sources to be obsolete or dangerous for various reasons.

    By example, Edison fuses are obsolete by the fact that insurance companies deem them potential hazardous. Though they still function/operate without a problem if they are not altered and are used as intended by manufacture.

    When the terms, "Useful Life" and "Life Expectancy", are used in describing a home it is typically a roof shingle/material. Where the shingle/material manufacture has given a warranty and the "Useful Life" or "Life Expectancy" terms are used in relation to those warranties. If the same rational is used then a circuit breaker would have an undefined (unlimited) useful life / life expectancy (lifetime). Old, a subjective value (10-20-30-50 years), would not be relevant determinate to useful function in relation to circuit breakers .


  8. #8
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    Quote Originally Posted by Roland Miller View Post
    after two trips at full available fault current they are supposed to be replaced
    I have never head of this. Can you refer me to documentation that explains this in more detail.


  9. #9
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    Quote Originally Posted by Roland Miller View Post
    after two trips at full available fault current they are supposed to be replaced
    Quote Originally Posted by Robert Rolleston View Post
    I have never head of this. Can you refer me to documentation that explains this in more detail.
    Robert,
    I think that it comes from a testing data report and may have been tied to commercial use. The statement is berried but I think is there, but subject to testing context. Thought I had a copy of the testing link but sadly couldn't find it, sorry.


  10. #10
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    I know this is an old thread but I wanted to quickly throw my 2c in. First, "The NACHI chart says that ground-fault circuit interrupters and arc-fault interrupters have a life of about 30 years, though a 2003 report prepared for the United States Consumer Product Safety Commission says arc- and ground-fault breakers, as well as regular circuit breakers, have a lifetime of 30 to 40 years." ( Googled info)Then You must take into consideration the location of the panel that the breakers are used in. Outdoor or indoor? Is it by the ocean or any water source? Does the ambient temperature reach 100 degrees F or drop bellow 0. All of these will influence the way a breaker operates and in some cases will restrict the breaker from opening! Just waiting for breakers to fail before replacing, in my opinion, is not safe. A yearly visual inspection after 15 years is my recommendation for breakers along with test-tripping GFCI and AFCI every month. Something that only takes a minute but can save lives in the long run.


  11. #11
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    Could you please tell me how a visual inspection of an installed breaker with a sealed case be of any value? What should someone look for.? Will you be able to see if an internal part has failed?

    All answers based on unamended National Electrical codes.

  12. #12
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    Default Re: Circuit breaker Life Expectancy / Useful Life

    Quote Originally Posted by JERRY HERRON View Post
    I know this is an old thread but I wanted to quickly throw my 2c in. First, "The NACHI chart says that ground-fault circuit interrupters and arc-fault interrupters have a life of about 30 years, though a 2003 report prepared for the United States Consumer Product Safety Commission says arc- and ground-fault breakers, as well as regular circuit breakers, have a lifetime of 30 to 40 years." ( Googled info)Then You must take into consideration the location of the panel that the breakers are used .............A yearly visual inspection after 15 years is my recommendation for breakers ...........
    What does Nachi use as their basis for suggesting a 30 yr life???

    The report you mentioned and linked was about "Savings Over the Life of the GFCI
    In 1982, at about the time that GFCIs entered widespread use, Underwriters Laboratories estimated that the expected useful life of GFCIs averaged about 40 years. 5 The benefits of GFCIs are expected to accrue over the entire useful life of the products.".

    The CPSC paper does not site where the author derived the 40yr life expectancy. Jerry, why don't you take on a quest to have them, the CPSC, provide you with the source and rational used to derive their number. Manufactures consistently state that there is no life expectancy of the breakers.

    Location and conditions have an effect on everything. By example, I have an exposed service panel (4ft off sand) that is 30ft from salt water and with a flood tide 3 feet from salt water. The panel and breakers only last about 8 years under those conditions. But it is unusual conditions and would not correlate to the normal consideration for determining "Useful Life".


    I agree with Jim, what would you be inspecting for after 15 yrs? The breaker mechanism is internalized and not visible.



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