(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 8 of 8

Thread: wires going in breaker box

  1. #1

    Default wires going in breaker box

    hi Guys

    Are there any regulations regarding how many NM cables I can put in the the knockout holes (of course with a clamp) in my breaker box. I noticed there are three 12 gauge in one hole, and three 14 gauge in another hole, Some have less, but did not notice any more than 3 cables in a hole.

    Also can i mix the 14 and 12 guage in the same hole or does it need to be in separate holes.


  2. #2
    Senior Robin Hood Guy Ian Gills's Avatar
    Join Date
    Jul 2007


    I am pretty sure you should only have one cable per clamp unless design specification says otherwise.

    As a general rule, it's one cable per cable clamp. There are cable clamps that are rated for more than one cable per clamp. To find out if the clamps that you have will accomodate more than one cable you would need to know who the manufacturer of the clamp is and check with them.

    The pros might also know an exception using nonflexible raceway sleeves or nipples.
    Last edited by Ian Gills; 10-13-2009 at 11:09 AM.

  3. #3
    Licensed Electrical Contractor Speedy Petey's Avatar
    Join Date
    Jun 2007
    NY State, USA


    Pretty much every typical NM cable connector I have seen or used was rate for two cables. Some are even rated for three.
    Answers based on the 2008 & 2011 NEC. If you're on the '14 already I feel sorry for you.

  4. #4



    I had this breaker box installed about one year ago, and the inspector looked at it so i know i passed the inspection. I notice that there were 3 12ga coming in a 3/4" opening with a metal clamp on the side of the box. Then there were about 2 cabled coming in from the top from what looks like a 1/2" opening but with a plastic push in connector.

    So I guess I'll just follow that pattern, no more than 3 with the 3/4" metal clamps and no more than 2 with the push in connector.

    Out of curiosity, if y box is inaccessible from 2 sides, and I run out of knock outs, what do electricians do if they want to add more cables?


  5. #5


    Out here, our panels are outside and it's always been common practice to run all the cables through one big hole ( thru an insulated bushing of course)

    If an inspector is worring about too many cables in a connector, he has too much time on his hands.

  6. #6
    DIY Member Ford2001's Avatar
    Join Date
    Sep 2009
    Manchester, Vermont

    Wink Service and breaker panel located on the exterior of your home

    220/221, your post dated, 10-14-2009

    "I have a question, you said out here all are panels are outside."

    My question what is the reason for circuit breaker panel in your location
    to be located outside.

    The last thing I want to do is go outside in the rain, looking for a trip
    circuit breaker, due to the fact that I was require to have my Service
    which includes the circuit breaker panel, located outside.

    I am I wrong, or can they also be located inside, that is the circuit breaker
    electrical panel.

    Thanks for any comments about this you wish to share.

  7. #7
    Electrical Contractor jbfan74's Avatar
    Join Date
    Jun 2007
    Newnan, GA


    It only rains 3 times a year where 220 is located!
    Yes I am A Pirate-Jimmy Buffett

  8. #8
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Cave Creek, Arizona

    Default rain

    Here, three times a year is a monsoon. The panels can be indoors, but then you have to have disconnect switch at the meter. The only indoor panels are usually subpanels.


Posting Permissions

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