plastic or metal junction boxes

Discussion in 'Electrical Forum discussion & Blog' started by Master Brian, Jan 7, 2009.

  1. Master Brian

    Master Brian DIY Senior Member

    Messages:
    368
    Location:
    Kansas
    Out of curiousity, what is the main difference besided the material. Why do some prefer metal and others prefer plastic. Is there any safety issues or is it just a matter of personal preferance?? My understanding is the metal ones need to be grounded.
  2. Alectrician

    Alectrician DIY Senior Member

    Messages:
    689
    Plastic boxes are far superior for NM cable wiring simply because the don't conduct electricity.

    Plus they are less expensive and easier to install.

    Some people think plastic = cheap.
  3. jamiedolan

    jamiedolan New Member

    Messages:
    28
    Location:
    Wisconsin
    Most plastic boxes are not rated for exposed work, i.e. concrete walls in the basement. So metal is much easier to use there.

    I've had some bad luck with some styles of plastic boxes cracking and breaking when installing them. I am sure some of the plastic boxes are better than others, I would suggest getting the better quality plastic boxes if that is the direction your going.

    Jamie
  4. codeone

    codeone Code Enforcement

    Messages:
    160
    Location:
    North Carolina
    Yes the metal ones do have to be bonded. (grounded)
  5. frenchie

    frenchie Jack of all trades

    The threaded holes for the screw that hold the device, strip out way more easily on plastic boxes.
  6. Alectrician

    Alectrician DIY Senior Member

    Messages:
    689
    I have never seen or stripped a screw hole on a Carlon blue box.

    I have seen some old grey Slater quick clip boxes circa 1980 where the little metal tabs broke completely out and I had to replace about a dozen of them. The Carlon boxes have a hole thru about 3/8" of pliable plastic. You can run drywall screws in ond out of them with ease if you need longer screws. They can't strip because they are not threaded.
  7. codeone

    codeone Code Enforcement

    Messages:
    160
    Location:
    North Carolina
    What size drill/driver are you using to run the screws in and at what torque setting to do this?

    Have seen this complaint quite often. Suggest you use one of the smaller compact drill/drivers with th torqu setting just enough to bottom out the screws.
  8. WV Hillbilly

    WV Hillbilly New Member

    Messages:
    178
    Location:
    WV
    I have seen light fixture boxes used for & called junction boxes . If installing a box in a ceiling that might have a light fixture or ceiling fan hung on it I always use a metal box . If the box is to be used for a junction box only , either should be fine .
  9. jamiedolan

    jamiedolan New Member

    Messages:
    28
    Location:
    Wisconsin

    If a plastic box is UL listed as a fixture / junction box, then it is fine to use for either.

    Use the correct box where necessary and it is all legal, metal or plastic.


    Jamie
    *I am pretty sure there are some schd 80 plastic rated for exposed work, but am not positive, I use metal.
  10. WV Hillbilly

    WV Hillbilly New Member

    Messages:
    178
    Location:
    WV
    I didn't say it wasn't legal to hang a fan or heavy light fixture on a plastic box . I just prefer a metal box for those applications .
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,049
    Location:
    Cave Creek, Arizona
    plastic

    quote; Some people think plastic = cheap

    So you must be one of the three or four people who do not think that. Would you REALLY hang a fan on a plastic box, unless the mounting bolts were fastened to the structure and not the box?
  12. Alectrician

    Alectrician DIY Senior Member

    Messages:
    689
    .


    Yeah. Me and the other three guys made the decision to install platic boxes in 98% of the houses built since 1980.



    Hey, I wasn't the one who changed this to a fan box thread. Try to keep up plumber.:rolleyes:
  13. codeone

    codeone Code Enforcement

    Messages:
    160
    Location:
    North Carolina
    is it UL listed for it. If it does it would pass for the weight rating of the box!
  14. Scuba_Dave

    Scuba_Dave Extreme DIY Homeowner

    Messages:
    885
    Location:
    South of Boston, MA
    I installed one of the heavier duty plastic fan boxes with support in my sunroom. I still didn't like the feel, support
    So I ran a 2x4 between the rafters & screwed the box to that
    It doesn't budge at all now

    I like the deeper plastic boxes - more room
    The existing metal boxes in this house were way too small
    My basement still has a few larger octagon metal boxes
    I installed plastic boxes at the ceiling level or on partition walls
    Unfinished basement, I didn't want any boxes down low
    We are near a stream & possibility of flooding if heavy rain & the sump pump failed
  15. frenchie

    frenchie Jack of all trades

    I didn't know rated fan boxes came in plastic.

    Huh. Learn something new every day.
  16. chris8796

    chris8796 New Member

    Messages:
    100
    Location:
    Illinois
    I prefer metal boxes just for the drywall cutting aspect. The easiest way to install drywall is to cut it with a rotozip or similar while it is screwed to the wall over the boxes. Metal boxes I can cut around perfectly, plastic boxes are touch and go. Since I don't do it often enough to develop a feel for it, I like the metal boxes. I also like them for the other reasons stated too. I still use plastic, especially "old" work boxes, but in general I'd prefer metal.
  17. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,049
    Location:
    Cave Creek, Arizona
    yeah, but

    Yeah. Me and the other three guys made the decision to install platic boxes in 98% of the houses built since 1980.

    That was not the question. The question was, WHY did you do it if it was for some reason other than price. AND labor being one factor in the price.
  18. Alectrician

    Alectrician DIY Senior Member

    Messages:
    689
    Ya lost me pal.

    Why did I do what???

    I thought the question was metal or plastic and I thought I answered it.



    The plastic fan boxes straddle...stradle....straddel....go around the ceiling joist and you screw thru them into the joist.
  19. thassler

    thassler New Member

    Messages:
    106
    Location:
    Tennessee
    http://www.terrylove.com/forums/images/smilies/smile.gif
    strad·dle (strdl)
    v. strad·dled, strad·dling, strad·dles
    v.tr.
    1.
    a. To stand or sit with a leg on each side of; bestride: straddle a horse.
    b. To be on both sides of; extend over or across: a car straddling the centerline.
    2. To appear to favor both sides of (an issue).
    3. To fire shots behind and in front of (a target) in order to determine the range.
    v.intr.
    1. To walk, stand, or sit with the legs wide apart, especially to sit astride.
    2. To spread out in a disorderly way; sprawl.
    3. To appear to favor both sides of an issue.
    n.
    1. The act or posture of sitting astride.
    2. An equivocal or a noncommittal position.
    3. The option to buy or sell a specific asset, such as a block of stock, at a predetermined price before a certain date.
    Idiom:
    straddle the fence Informal
    To be undecided or uncommitted.
  20. Ian Gills

    Ian Gills Senior Robin Hood Guy

    Messages:
    2,777
    Location:
    USA
    I only use metal boxes because I am a craftsman. And I do not feel comfortable using plastic wall boxes with armored cable.

    Make sure all your boxes are accessible. We don''t want to see these things behind drywall without an access panel.

    One of the benefits of a suspended ceiling in a basement...
    Last edited: Jan 17, 2009
Similar Threads: plastic metal
Forum Title Date
Electrical Forum discussion & Blog Aluminum wire and plastic conduit or copper and metal? Oct 22, 2008
Electrical Forum discussion & Blog Grounding after changing to plastic service line Feb 27, 2012
Electrical Forum discussion & Blog running cat6s inside plastic conduit with 120v Feb 19, 2011
Electrical Forum discussion & Blog How to remove plastic strain relief connector? Jan 4, 2011
Electrical Forum discussion & Blog Plastic Wall Box May 27, 2010

Share This Page