Box extension

Discussion in 'Electrical Forum discussion & Blog' started by Bassman, Dec 3, 2007.

  1. Bassman

    Bassman DIY Member

    Messages:
    94
    Location:
    Ventura, CA
    I have a box in the wall under my sink that's just a junction box, no device. The problem is that through bad planning the box got buried very deep into the wall so I need to extend it so I can cover it. I'm talking 2 inches from the inside of the cabinet to the edge of the plastic single box. Are there commercially available extenders that deep? Can I make one? Thanks.
  2. 480sparky

    480sparky In the Trades

    Messages:
    149
  3. Bassman

    Bassman DIY Member

    Messages:
    94
    Location:
    Ventura, CA
    Thanks, I know about those but it's still going to be short by over 3/8". I found some stackable ones at www.receptxtenders.com. Definitely the ticket and my punishment will be paying 7.50 to ship $3 worth of plastic.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,059
    Location:
    New England
    My local HD has a variety of the extender rings normally instock. They may not have the box extender.
  5. statjunk

    statjunk DIY Senior Member

    Messages:
    542
    Don't bother with a box extender and just get really long screws. Or go half and half. Buy a standard box extender and then use long screws.

    Think outside the box.

    Tom
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,059
    Location:
    New England
    While I'm not certain, it is my understanding that the box must extend past any combustible components. If the box was going through the back of a wood or composite cabinet, that would be a technical violation. Any arcing might ignite the cabinet. The extenders are cheap...and solve the problem.
  7. 480sparky

    480sparky In the Trades

    Messages:
    149
    If the wall material is combustible, the box must be flush with or project out from the surface.

    If the wall is non-combustible, it cannot be any further back into the wall than ¼".

    2005 NEC 314.20.
  8. sbrn33

    sbrn33 Electrical Contractor

    Messages:
    31
    Location:
    Fremont, NE
    It's called a handy box extension ring. It will fit right on the existing box and make every thing safe and up to code. The only hard part is that you will probably have to use a ground clip to ground it. They are ussaly only an inch and a half so you might still have to use the Arlington extension but a least it will be safe.
    To the guy who said "just use longer screws" shame on you. Please never give electrical advice again, and please-please don't ever do any electrical work as you are a hack.
  9. statjunk

    statjunk DIY Senior Member

    Messages:
    542
    Sbrn33,

    I should have asked what his wall material was made out of. If his walls are made of drywall it isn't that out of the question to use a longer screw to hold a plate onto a box.

    Tom
  10. kd

    kd New Member

    Messages:
    207
    2 inch thick drywall? It is OK to use two 1.5 inch extension boxes and have the box stick out past flush with the cabinet wall.
  11. Bassman

    Bassman DIY Member

    Messages:
    94
    Location:
    Ventura, CA
    It's not 2" drywall. We had to shear the wall with 3/4 ply, then 1/2 drywall, then a cabinet back. Bad planning. Every other box on that wall I remembered to install adjustable boxes. This one just got lost in the shuffle.

    Sbrn33--Can I put that handy box extension onto the plastic box and then another ring if needed? Grounding with a clip is no problem, I have some of those. If I can just keep stacking extensions my problem is solved.
  12. 480sparky

    480sparky In the Trades

    Messages:
    149

    You still would need 3" of free conductors once you put all the extensions on.
    300.14.
  13. Bassman

    Bassman DIY Member

    Messages:
    94
    Location:
    Ventura, CA
    I think I still have that. If not, can I extend them? There's no device in this box, it's purely a junction box.
  14. 480sparky

    480sparky In the Trades

    Messages:
    149
    Technically, no. Device or not, there still needs to be 3".
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