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  1. #1
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    May 2007
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    Default Tripless circuit breaker?

    I am not familiar with devices such as this and I would like to "phone a friend". Any input would be appreciated. Well....any helpful, kind, well-mannered, friendly input would be appreciated.

    This cabinet/panel is just to the right of the main service entrance and panel. It is supplied by a 100 amp breaker. The breaker at the top of photo is the AC disconnect. The mystery device is at the bottom of the cabinet (sorry about the photo centering). The mystery device supplies the storage/building shop.

    Thanks!

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  2. #2
    Join Date
    Mar 2007
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    Ormond Beach, Florida
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    Default Re: Tripless circuit breaker?

    That is just a tap (have a mental blank on its name??), the tap and the feeders from the tap need to be rated the same as the service entrance conductors (unless the feeders - tap conductors - meet one of the tap rules).

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  3. #3
    Join Date
    Aug 2008
    Location
    Maryland
    Posts
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    Default Re: Tripless circuit breaker?

    I agree that it looks like a tap without overcurrent protection.

    All answers based on unamended National Electrical codes.

  4. #4
    Join Date
    Dec 2007
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    Chico,Ca
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    423

    Default Re: Tripless circuit breaker?

    Subfeed lugs


  5. #5
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    May 2007
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    Tyler, TX
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    Default Re: Tripless circuit breaker?

    Thanks everyone. The devices were marked Square D and I wasn't concerned, just interested.

    Bruce Thompson, Lic. #9199
    www.TylerHomeInspector.com
    Home Inspections in the Tyler and East Texas area

  6. #6
    Join Date
    Dec 2007
    Location
    Chico,Ca
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    423

    Default Re: Tripless circuit breaker?

    Quote Originally Posted by JB Thompson View Post
    Thanks everyone. The devices were marked Square D and I wasn't concerned, just interested.

    That is a Challenger* or a Bryant/Westinghoue/C-H BR loadcenter, from what I understand there is not any SQ D breakers / accessories listed / classified for other makes of panels.

    * In later years the BR line loadcenters & Challenger looked the same as they were both Westinghouse subsiduaries.


  7. #7
    Join Date
    May 2007
    Location
    Tyler, TX
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    719

    Default Re: Tripless circuit breaker?

    My bad. It is a Cutler Hammer box (I zoomed in on another photo to look) with CH devices.

    Bruce Thompson, Lic. #9199
    www.TylerHomeInspector.com
    Home Inspections in the Tyler and East Texas area

  8. #8
    Join Date
    Mar 2007
    Location
    georgia
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    112

    Default Re: Tripless circuit breaker?

    I am assuming that the 100 amp breaker is the main being reverse feed did it have the screw intalled as a hold down?


  9. #9
    Join Date
    Mar 2007
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    Ormond Beach, Florida
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    Default Re: Tripless circuit breaker?

    'Subfeed tap' ... got it ... thank you Rollie.
    Bruce,

    Remember, the feeders need to be sized appropriately for the main disconnect size as there is no other overcurrent protection.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  10. #10
    Join Date
    May 2007
    Location
    Tyler, TX
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    719

    Default Re: Tripless circuit breaker?

    Quote Originally Posted by paul hardy View Post
    I am assuming that the 100 amp breaker is the main being reverse feed did it have the screw intalled as a hold down?
    Yes the screw was installed.

    Bruce Thompson, Lic. #9199
    www.TylerHomeInspector.com
    Home Inspections in the Tyler and East Texas area

  11. #11
    Join Date
    May 2007
    Location
    Tyler, TX
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    719

    Default Re: Tripless circuit breaker?

    Quote Originally Posted by Jerry Peck View Post
    'Subfeed tap' ... got it ... thank you Rollie.
    Bruce,

    Remember, the feeders need to be sized appropriately for the main disconnect size as there is no other overcurrent protection.
    So the feeders coming from the "subfeed taps" should be sized for the 100 amp breaker? Or are you saying they should be sized appropriately for the subfeed tap? In which case, what would that size be?

    Bruce Thompson, Lic. #9199
    www.TylerHomeInspector.com
    Home Inspections in the Tyler and East Texas area

  12. #12
    Join Date
    Mar 2007
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    Default Re: Tripless circuit breaker?

    Quote Originally Posted by JB Thompson View Post
    So the feeders coming from the "subfeed taps" should be sized for the 100 amp breaker? Or are you saying they should be sized appropriately for the subfeed tap? In which case, what would that size be?
    Let's say you have a 100 amp breaker as the main disconnect, and that the 100 amp breaker is protecting the bus bars in that service equipment (which it is), and that the sub feed tap is connected off the bus bars with no overcurrent protection (which it is and has no overcurrent protection), and that the feeders going from the subfeed tap terminals are only 60 amp rated - the only overcurrent protection provided for those 60 amp feeders is that 100 amp main breaker. This means you *could* draw 100 amps through the 60 amp rated conductors before the 100 amp main tripped.

    Now let's presume that the subfeed tap has 125 amp rated conductors going from the subfeed tap terminals, which are also protected only by the 100 amp main breaker ... is there any need to have conductors which have a 'higher' rating than that 100 amp main? If you try to pull more than 100 amps through those feeder conductors the main should trip, and will probably trip well before you get close to 100 amps through those feeders as there are also other circuits drawing current through the main breaker.

    That means that you could feed a 150 amp panel with 150 amp rated feeders from that subfeed tap, but the most you will ever get through those feeders will be 100 amps before the main breaker trips (presuming that all other circuits in that panel drawing -0- amps). So why spend the extra money? Would it be wrong? No.

    Could it have been planned? Yes. Because they may have intended to, or still may intend to, replace that 100 amp panel and its main and install a 200 amp service, and the subfeed tap feeders are already sized for that future expansion.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  13. #13
    Join Date
    Jul 2010
    Location
    Washington
    Posts
    70

    Default Re: Tripless circuit breaker?

    The sub feed tap conductors look to be undersized (if the panel has 100A at the main). JB is this what you reported or am I missing something?


  14. #14
    Join Date
    Mar 2007
    Location
    Las Vegas, NV
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    222

    Default Re: Tripless circuit breaker?

    You reported the white colored load carrying conductor as well, correct JB?

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