Air Sealing Electrical Boxes (Expanding Foam.)

Discussion in 'Electrical Forum discussion & Blog' started by molo, Jun 24, 2012.

  1. molo

    molo Member

    Messages:
    848
    Location:
    cold new york
    Hello,

    I'm working on a new renovation with new wiring and access to the open framing. I would like to prevent air leakage around all electrical boxes.

    One thought I have is to use expanding foam around the outside of the boxes. Is this OK?

    Thanks in Advance,
    Bill
    Last edited: Jun 24, 2012
  2. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,559
    Location:
    North Carolina
    Depends on the foam
    read the instructions
  3. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    There are specific foams for closing holes drilled to chase NM thru framing. Look at some of that.
  4. ss3964spd

    ss3964spd New Member

    Messages:
    41
    Anyone know what this foam is and where it can be found?
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,157
    Location:
    NW Ontario, Canada
    Google is your friend. Search for:

    fireblock foam electrical
  6. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Amen.

    I saw rows and rows of it at Home Despot just yesterday.
  7. molo

    molo Member

    Messages:
    848
    Location:
    cold new york
    I talked to a rep. at Dow today. They said that their standard "great stuff" foam is OK around electrical boxes and insulated wires. However, it is not OK inside the box or in contact with bare copper.
  8. Chad Schloss

    Chad Schloss Member

    Messages:
    330
    Location:
    USA
    if i were you, i wouldn't use the normal great stuff. get the stuff for windows and doors. it does not expand as much and will not push your boxes out of square if you use too much. it will bow window frames if used incorretly, i've done it myself.
  9. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    I'd definitely try to ask a local electrical inspector.
  10. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    I doubt that fireblock caulk or foam is required. The OP is not sealing fire rated areas, except for maybe floor penetrations and that is only is the floor is a rated assembly.
  11. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    My concern would be that certain products would be banned as blocks around boxes due to their flammability.
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