This may be a duplicate of What are the codes for electrical wiring in attics?

I have an attic which is accessible via a ladder through an access panel in the garage and in a bedroom. The trusses and joists are all open and there is blown in insulation up to the height of the joists. In the future I need to have more insulation installed. Is it safe (up to code) to cover the junction boxes with more insulation or is this considered concealing them? Would I have to raise all of the junction boxes above the insulation for each light fixture, fan, etc.?

  • the junction boxes are available from the ceiling side though, correct? if so they are not concealed...
    – Steven
    Commented Mar 28, 2013 at 13:07
  • Not all of them. Some of them lead to recessed lighting in bathroom soffits or are acting as splices.
    – Evil Elf
    Commented Mar 28, 2013 at 13:10

6 Answers 6


Your best bet in this case is to contact the local inspector, since this situation may be open to interpretation. The most fitting code states:

National Electrical Code 2008

ARTICLE 314 Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures

314.29 Boxes, Conduit Bodies, and Handhole Enclosures to Be Accessible. Boxes, conduit bodies, and handhole enclosures shall be installed so that the wiring contained in them can be rendered accessible without removing any part of the building or, in underground circuits, without excavating sidewalks, paving, earth, or other substance that is to be used to establish the finished grade.

Exception: Listed boxes and handhole enclosures shall be permitted where covered by gravel, light aggregate, or noncohesive granulated soil if their location is effectively identified and accessible for excavation.

Article 100 Definitions

Accessible (as applied to wiring methods). Capable of being removed or exposed without damaging the building structure or finish or not permanently closed in by the structure or finish of the building.

It may or may not be acceptable, depending on if the inspector considers insulation "part of the building".

If you do end up covering the boxes, it might be a nice idea to mark/flag them in some way. This way you; or any other future owner, will be able to locate them later if need be.

  • This has to be a common situation. Do people just blindly insulate their attics without any thought of ever having to access the wiring up there again?
    – Evil Elf
    Commented Mar 28, 2013 at 16:51
  • If it's done by the homeowner themselves, they would likely never give it a thought. If it's done by professional insulation experts, they usually know how to handle this type of stuff.
    – Tester101
    Commented Mar 28, 2013 at 17:12
  • 5
    Even the professionals don't always give much thought; the original blown-in insulation in my attic covers every last inch of wiring and junction box. Each time I go up there, I bring a broom and sweep around a large area to simply find a cable, box, or wall penetration. Commented Mar 29, 2013 at 2:57

The junction boxes that contain splices and are not accessible from the ceiling below should be exposed - not covered by insulation. If enough slack is present in the cables between the boxes, you may be able to raise them up a bit and mount them on trusses or other exposed framing members without having to run new wire.

  • 4
    Is there a NEC code to reference on this?
    – Evil Elf
    Commented Mar 28, 2013 at 13:27
  • 2
    Can you site a source for this information, or is this just your opinion?
    – Tester101
    Commented Mar 28, 2013 at 14:01
  • All boxes shall be accessible. NEC 314.29 -The exact interpretation of this is up to the local inspector. Some states / municipalities consider insulation covered boxes to be "accessible", and some do not. As a practical matter, in my own opinion, it's a bad idea to hide junction boxes under insulation where finding them will be difficult when troubleshooting future problems or doing future modifications.
    – Paul
    Commented Mar 29, 2013 at 1:39
  • Would there be any benefit to running a piece of brightly-colored string or other such material between a each box or other item of interest and a sign which identifies it?
    – supercat
    Commented Jan 27, 2014 at 23:35

I would suggest that you install access panels in the ceiling for these concealed boxes, and then cover them with insulation. Not covering them with insulation could lead to moisture problems because the cold attic air will hit warmer air around the un-insulated box which is warmer because the other side of it (ceiling) is a conditioned space.

Also, in the event you need to access the box, it is easier to access it from the conditioned space and not have to crawl around your attic.


If it wasn't done during original construction and with any additional penetrations of the attic envelope, fire caulk sealing of any gaps around the j-boxes or bare wire/plumbing stacks will greatly assist your insulation staying dry. Be sure no additional vapor barrier is added over your existing insulation.


I am in the same situation adding some recess lighting. I chose to hold off the installation of the junction box and get some wood to raise it. Reasoning, I was not sure about the code, it's easy to do and will be better for me or anyone who may want to add on later to the box. Some wood, a nail gun or some plates, and some screws and you're ready to go.

  • I used those Tyco splices originally, but I replaced them with metal junction boxes and hung them on the underside of the roof rafters. The insulation job was a whopping pain in a cape cod.
    – Evil Elf
    Commented Mar 16, 2015 at 11:19

Caned / recessed lights have built in jboxes and are rated to be buried in insulation. So no raising them above insulation or opening ceiling to ad exposed box covers. Come on people. Really. Yes cover them

  • 2
    Hello, and welcome to Stack Exchange. Not all cans are rated insulation contact. Commented Sep 30, 2016 at 0:33

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