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Thread: Circuit Breaker teardown and defective Siemens latching mechanism

  1. #111
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    mbrooke, Late last year we were discussing about cable leakages and appliance leakages of current which you said was the reason why European RCD uses 30mA tripping threshold instead of 5mA.

    Since my 5mA GFCI protection is really whole house now (100% protection even the lights) spread into 6 GFCI breakers in main panel. I'd like to know something about the dielectric leakages of current. if the dielectric insulation in cable or appliance is not good. Where will the current leak to? Is it more apparent when there are EGC or GEC installed, like in Europe? But without any EGC or even GEC. Where will the current leak to?

    So far no nuisance tripping yet for my whole house GFCI protection. I'm thinking where cable leakages and appliance leakages can occur. Did you mean like the water pump put on concrete floor, but if it is insulated from the floor, how will the current leak?

  2. #112
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    Quote Originally Posted by tersh View Post
    Is it stated in the breaker itself that it can take 2 conductors? Where are such written?



    Also they must be same size. If one is larger or smaller, the smaller one can slip.
    Last sentence in 110.14(A): Terminals for more than one conductor and terminals used to connect aluminum shall be so identified.

    No rule stating where it must be written, but is usually on the breaker, lug, etc. somewhere. If it says something like 14-2 AWG that typically means one conductor in the size range mentioned. If it says (1) 600 MCM-4 AWG (2) 250 MCM-1/0 AWG that means one conductor between 600MCM and 4 AWG or two conductors (same size and type) between 250 MCM and 1/0 AWG.

    Quote Originally Posted by tersh View Post
    You have seen tons of double tapped breakers in residential? Don't they have annual inspections?
    That there is funny
    I live for today, I'm just a day behind.

  3. #113
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    Quote Originally Posted by kwired View Post
    Last sentence in 110.14(A): Terminals for more than one conductor and terminals used to connect aluminum shall be so identified.

    No rule stating where it must be written, but is usually on the breaker, lug, etc. somewhere. If it says something like 14-2 AWG that typically means one conductor in the size range mentioned. If it says (1) 600 MCM-4 AWG (2) 250 MCM-1/0 AWG that means one conductor between 600MCM and 4 AWG or two conductors (same size and type) between 250 MCM and 1/0 AWG.

    That there is funny
    kwired. In your expert opinion. How many times do you think you can bend up and bend down the same portion of the wire for say AWG 3 and AWG 2 or in between before they suffer microscopic breaks in the cooper metal?

  4. #114
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    Quote Originally Posted by tersh View Post
    Is it stated in the breaker itself that it can take 2 conductors? Where are such written?
    Molded into the body of the breaker for 14, 12, & 10 wire; same with CH.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  5. #115
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    Quote Originally Posted by tersh View Post
    kwired. In your expert opinion. How many times do you think you can bend up and bend down the same portion of the wire for say AWG 3 and AWG 2 or in between before they suffer microscopic breaks in the cooper metal?
    How do you come up with these questions???

    -Hal

  6. #116
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    Quote Originally Posted by hbiss View Post
    How do you come up with these questions???

    -Hal
    I didn't just think up the questions. All my questions were due to actual applications issues:




    The electrician is migrating the panel from plug in to din rail and he bends the wires up and down. So I wonder how many times it can happen before micro cracks in the cooper can occur. I was not asking about the radius which we know but trying to bend with minimum radius up or down (or in opposite directions). If he does it 10 times, the wire can fracture. It's 30mm^2 or exactly between AWG 3 and AWG 2. But I wonder if less than 5 times, how would the wires behave.

  7. #117
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    Why don't you let your "electrician" worry about it?

    -Hal

  8. #118
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    Quote Originally Posted by hbiss View Post
    Why don't you let your "electrician" worry about it?

    -Hal
    Since it's not his. He doesn't care. He bends the wires in different positions up and down left and right with multiple bending at opposite direction. I'm afraid there may be microcracks hence asking how many they can actually be bend back and forth. 30mm^2 is exactly between AWG 3 and 2.

  9. #119
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    Quote Originally Posted by tersh View Post
    mbrooke, Late last year we were discussing about cable leakages and appliance leakages of current which you said was the reason why European RCD uses 30mA tripping threshold instead of 5mA.

    Since my 5mA GFCI protection is really whole house now (100% protection even the lights) spread into 6 GFCI breakers in main panel. I'd like to know something about the dielectric leakages of current. if the dielectric insulation in cable or appliance is not good. Where will the current leak to? Is it more apparent when there are EGC or GEC installed, like in Europe? But without any EGC or even GEC. Where will the current leak to?

    So far no nuisance tripping yet for my whole house GFCI protection. I'm thinking where cable leakages and appliance leakages can occur. Did you mean like the water pump put on concrete floor, but if it is insulated from the floor, how will the current leak?
    Through a person and to ground.
    I'm in over my head...

  10. #120
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    Quote Originally Posted by mbrooke View Post
    Through a person and to ground.
    I see. This explains why a 5mA GFCI can protect an entire house without leakages because all the devices were isolated. Should there be EGC or GEC. Then it can nuisance trip on dielectric insulation decay and current leakages to the EGC or GEC.

    I know EGC is important so in the event of ground fault, it should trip the regular breaker immediately without waiting for a person and a ground via GFCI, which is only used for backup in the US.

    But if the appliances have GEC. It should trip the GFCI as well so GEC should be at least a minimum. Hence will assign local electrical engineers for possible GEC installation and breaking concrete in the parking area next time.

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