Why no 'Hidden' junction boxes?

17 years ago

In part, the reason for building codes is to hold contractors to a certain minimum safety standard.

So I can easily understand building codes like GFCI outlets for wet locations (kitchen & bath).

But what is the reasoning for the code that basically states that all junction boxes must be accessible?

I just don't see the "safety" factor in such a code. The splice doesn't know that it's hidden, and the wire is more protected in a box than just running inside the wall. So the code isn't written as a means of preventing a fire (like codes that specify minimum wire sizes do). Wire in the wall is stapled so it can't go anywhere, so there isn't any advantage from a stand point of being able to pull the wire out later.

Now I can guess as some reasons, such as being able to maintenance the junction in the future to check for corrosion or something like that. But nobody "maintenances" electrical wire (except for when something has gone wrong). So given that you could put a note on exposed wire indicating there is a hidden junction box (in case that needed to be known in the future for trouble shooting) why isn't that allowed? (i.e. to the best of my knowledge, there isn't an exception to "no hidden junction boxes" "if you do X").

Just because a junction box is hidden behind a wall isn't going to make it more likely that

Through sources like this forum, I've learned that it is against code to have a junction box that is hidden (i.e. sealed up behind a wall).

Comments (3)

doc8404
17 years ago
Don't try to discern the reasoning behind any particular NEC requirement. You'll lose your mind on some of them. :)

I gather you view the NECs stance on j-boxes is that it is for protection of the conductors. Nope - it's for accessibility for it's own sake. NEC requires a j-box when a splice or tap is made - NEC 2002 Article 300.13. (Busway conductors are exempt and outside what you are asking about). Splices and taps must be accessible according to Art 300.15. Therefore - if you have a splice, you need a j-box. If you have a j-box, it must be accessible.

2002 NEC

300.13 (A) - Wiring Methods - Mechanical and Electrical Continuity. General - Splices or taps are prohibited within raceways unless the raceways are equipped with hinged or removeable covers. (The j-box is considered a raceway).

300.15 Wiring Methods - Boxes, Conduit Bodies, or Fittings Methods with Interior Access.
..... a box or conduit body complying with Art. 314 shall be installed at each conductor splice point.
bus_driver
17 years ago
This question is best answered with other questions. If the box is hidden, how does a service person know of it's existence? And if they suspected that it existed, how would they locate it? Failed splices are one of the most likely problems with premises wiring. If you never experienced any problems with your system, it is a testament to the value of the code and enforcement of it.
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tom_o
17 years ago
So you don't mind someone knocking holes in your walls to gain access to one of those connections when it goes bad? Don't hold your breath waiting for someone to put a note on the wiring, it's hard enough to get someone to fill out a panel schedule like they're supposed to.

If you feel strongly about allowing concealed junction boxes, when the 2008 NEC comes out, the clock will start ticking for proposals to change the 2011 NEC. You will be able to download the forms from NFPA.org at that time.