My new home is almost done being built, and one of the extras I asked for was for two of the rooms to have junction boxes in the ceiling suitable for hanging a ceiling fan in the future.

The light fixtures haven't been installed yet so I can see inside the junction boxes but can't really distinguish between the braced boxes and the regular boxes. The attic is extremely limited access so I want to avoid crawling around up there to look for a brace.

Is there a quick or easy way to distinguish between a junction box that is able to carry the weight of a ceiling fan safely versus one that is not? I could just take their word for it but they haven't had a very reliable track record so far when it comes to following through with my requests even when they tell me they will do it.

2 Answers 2


If the box was installed recently in accordance with National Electrical Code (NEC), the box should be labeled if it's rated to support a ceiling fan.

NEC 2008
314.27 Outlet Boxes.
(D) Boxes at Ceiling-Suspended (Paddle) Fan Outlets. Outlet boxes or outlet box systems used as the sole support of a ceiling-suspended (paddle) fan shall be listed, shall be marked by their manufacturer as suitable for this purpose, and shall not support ceiling-suspended (paddle) fans that weigh more than 32 kg (70 lb). For outlet boxes or outlet box systems designed to support ceiling-suspended (paddle) fans that weigh more than 16 kg (35 lb), the required marking shall include the maximum weight to be supported.

If it's not labeled, the box is still required to support at least 50 lbs.

314.27 Outlet Boxes.
(A) Boxes at Luminaire Outlets. Boxes used at luminaire or lampholder outlets in a ceiling shall be designed for the purpose and shall be required to support a luminaire weighing a minimum of 23 kg (50 lb). Boxes used at luminaire or lampholder outlets in a wall shall be designed for the purpose and shall be marked to indicate the maximum weight of the luminaire that is permitted to be supported by the box in the wall, if other than 23 kg (50 lb). At every outlet used exclusively for lighting, the box shall be designed or installed so that a luminaire may be attached.

If the box was installed before this code was adopted; or in an area that does not follow NEC, you'll likely have to cut/drill some exploratory holes to determine if the box is properly braced.

  • 1
    Just a note. In the quoted text (and throughout NEC) "outlet" is not the same as "receptacle".
    – Tester101
    Nov 28, 2012 at 15:31
  • 3
    @maple_shaft The brace on a ceiling fan box is to deal with vibration and oscillation from the fan; just because your fan is lighter than 50lb doesn't mean you can safely use it in a regular box
    – Niall C.
    Nov 28, 2012 at 16:18
  • @NiallC. Of course... I will have to check and see what was installed and report back Nov 28, 2012 at 16:55
  • @maple_shaft: What did they install in the end? Apr 17, 2013 at 20:56
  • @unforgettableid They installed the right thing but it just appeared to be this flimsy piece of plastic and I didn't trust the plastic screw holes to last a long time. I know it is complete overkill but I lagged the fan through the box directly into the 2x4 brace the box was attached to. The weakest point then are now the nails holding the 2x4 brace between the trusses. I could probably tie the end of a hammock to the base of the fan now :) Jun 4, 2013 at 18:36

Ceiling fan boxes are usually one of a few common types. All should have a fan support statement on a sticker or stamped onto or molded into the box.

The most common has an adjustable crossbar built into it, and you can see the mounting screws protruding through the floor of the box:

enter image description here

Another type wraps around the ceiling joist. They're apparent by the shape molded into the box itself:

enter image description here

Then there are a few with side-mount flanges. They'd be less obvious as fan-rated, but should contain markings indicating that they are:

enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.