User Tag List

Results 1 to 8 of 8

Thread: 2011 NEC art. 210.12(B) AFCI protection for Extensions or Modifications-Dwelling Unit

  1. #1
    Join Date
    Apr 2009
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    2011 NEC art. 210.12(B) AFCI protection for Extensions or Modifications-Dwelling Unit

    How do you comply with 2011 NEC art. 210.12(B) when the circuits in the breaker panel are multi-wire branch circuits?

    Should there have been an exception, or how about a $150.00 2pole AFCI? Sounds like not much thought went into this one.

  2. #2
    Join Date
    Feb 2003
    Location
    Minnesota
    Posts
    7,134
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by sparky2k View Post
    How do you comply with 2011 NEC art. 210.12(B) when the circuits in the breaker panel are multi-wire branch circuits?
    We're all waiting on the manufacturer's release of the AFCI device.

    Till then, we're stuck with AFCI breakers (unless there is local ordinance that gives some relief).

    The GE single pole combination-type AFCI breaker (MOD 3) is really the only breaker available now that can handle existing multiwire branch circuits. Of all the AFCI combo breakers, the GE is the only one so far that doesn't have a GFI like component in it's circuitry.

    A GE single pole combination-type AFCI MOD 3 breaker can be connected to one side of an existing multiwire branch circuit, by its own installation instructions.

    It's either that or run all new branch circuit to refeed the outlet that is being repaired or modified.
    Another Al in Minnesota

  3. #3
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    34,729
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Some manufacturers make a DP Afci. These will work on a mwbc.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  4. #4
    Join Date
    Feb 2003
    Location
    Minnesota
    Posts
    7,134
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Dennis Alwon View Post
    Some manufacturers make a DP Afci. These will work on a mwbc.
    Well, yes. The OP commented on that. ~$150 DP AFCI vs ~ $39 SP GE MOD3 AFCI.

    The difficulty of the existing circuit holding with the SqD/CH/Siemens AFCI because of ground fault leaks and/or neutral cross circuiting, to me, is the hidden challenge. That is, the SqD/CH/Siemens double or single pole AFCIs require an absolutely correctly wired neutral and very limited ground fault bleed before they will stay on at all.

    The GE MOD3 AFCI is only pure arc fault discrimination without comparing the hot and neutral currents.

    When I am "modifying or repairing" an existing outlet, and am forced, by 2011 NEC 210.12(B), to add AFCI to an existing MWBC of unknown or questionable workmanship I am completely gambling on what kind of "call back" time I am in for.

    To me, the simplicity of setting a small GE subpanel for its MOD3 AFCI and reliable operation (read low likelihood of call backs) is the convincing factor.

    The second choice is to run a new homerun to the modified outlet.
    Another Al in Minnesota

  5. #5
    Join Date
    Apr 2009
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    mod 3 breaker

    Thanks everybody, not sure if about installing a tie handle since I have a multi wire branch circuit.
    Sparky2k

  6. #6
    Join Date
    Feb 2003
    Location
    NE Arkansas
    Posts
    2,221
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Yea ... installing a handle will not work. You really need to use a 2-pole breaker. $$$$$

    The 2011 has a number of other new restrictions on MWBC's. It appears to me as though they're trying to ban them without directly saying so .... sort of the NFPA equivalent of the city of Gary, Ind. circumventing state laws by refusing to distribute the necessary forms to applicants (another topic, another forum).

  7. #7
    Join Date
    Feb 2003
    Location
    Minnesota
    Posts
    7,134
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by renosteinke View Post
    Yea ... installing a handle will not work. You really need to use a 2-pole breaker. $$$$$
    210.4(B) only requires a "simultaneous disconnect", not a "common trip".

    Take a look at this GE document. Note at the end of the paragraph that GE tells you to use a handle tie on their CAFCI single pole when used on a multiwire branch circuit (MWBC).

    Think about it. This permits me to put a GE MOD 3 CAFCI on one side of a MWBC beside a plain old single pole breaker and use a handle tie. That's a huge advantage. Just try it with a Square D, Siemens or CH single pole . . . they'll never hold because of the ground fault detecting portion of the AFCI circuitry. But the GE MOD 3 has no ground fault detection. It is pure AFCI.
    Another Al in Minnesota

  8. #8
    Join Date
    Apr 2009
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    210.4(B) only requires a "simultaneous disconnect", not a "common trip".

    Really good al, will try this on the next one.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •