We recently discussed the intricacies and code requirements about how you can insulate a junction box. As a result of that article, many DIY-ers asked whether it is a good idea to drywall over a junction box. This might seem necessary when you need to make repairs to the current wiring in place or when you’re trying to extend a new wire.
We believe that the question here shouldn’t be whether you can or not; the question should be whether you should drywall over a junction box – regardless of whether you’re planning on doing so with or without insulation.
If the wire isn’t long enough or whether a small part of the wire underneath your drywall is damaged, it is never a good idea to install a junction box under the drywall or tiles. This is because it is a code requirement for junction boxes to remain accessible – not to mention the problems you’ll likely create for your future self if you cover it up permanently. There are some ways, though, that you can adopt if you need to extend a concealed wire.
Can you Drywall Over a Junction Box?
Hidden wiring is much more appealing than wires hanging off the walls or conduits running around your fixtures. However, there are also numerous considerations you have to make to ensure electrical safety – as recommended by code.
Applying drywall over a junction box is never a good idea. According to the code, your junction boxes should always remain accessible, regardless of how good of a splice you made. Yes, it is possible that you made a rather tight connection and that it will never go bad but because the wires tend to run hot when heavier loads are applied (or simply during the summer season), they present a fire hazard, to say the least.
So, the best option you have is to not cover junction boxes. If you really, really must maintain the aesthetic appeal of your wall, we recommend you work in a manner where you don’t need a junction box at all; consider replacing the wire completely. No splices or joints will mean there is no need for a junction box, which should solve the problem you have. You can then pass the wire from underneath the drywall easily. You’ll thank yourself for that.
Code Requirements – UK
The UK electrical code doesn’t exactly say a direct ‘no’ for whether you can drywall over a junction box or not. Instead, there is the same requirement as we mentioned above, i.e., you can put drywall over a junction box so long as it’s accessible. However, in the UK, drywall isn’t exactly the go-to construction material. It is only used in storerooms or partitions, and therefore, anything behind it is usually accessible.
A prime example of this is the small ‘room’ Harry lived in under the stairs – i.e. Harry Potter’s cupboard under the stairs!
If we are to consider the same question for concrete, i.e., can you apply concrete over a junction box, the answer is a resounding ‘no.’ You can apply drywall on a junction box, though, if you make the same accessible.
At the same time, electricians across Europe will agree that In the UK that it is NEVER a good idea to confine junction boxes. They agree that for maximum safety and code compliance, the best policy is to avoid using junction boxes altogether. This is because junction boxes have a way of becoming nothing short of a nightmare to fix as it is; imagine if it is in a hard-to-reach place.
Another important consideration is that it might not always be possible to connect all the wires coming into sockets or ceiling roses, in which case junction boxes might become a necessity. Even in this case, it is not advisable to try and hide a junction box. Remember, nobody cares if you have a junction box in the middle of a wall. Nobody should care, either. It is a normal part of a house just like sockets and fixtures are. The only difference is how neatly you place it. This is known as cable management
If you really must hide it, electricians recommend that you try and place the junction box on top of a cupboard (not behind it!) or perhaps at a corner – somewhere you can’t see it unless you’re deliberately looking for it.
Code Requirements – US
As far as the US electrical code is concerned, it directly says no – as in it should NEVER be attempted. If you really must bury something behind the drywall, it should be a continuous run of wire. The code requires that any sort of connection, be it repair work or a splice, should be easily accessible. This also applies to insulation.
If an inspector comes over and finds that a joint or a junction box has been buried deliberately underneath the drywall, you will be given a set number of days (with respect to the state) to fix it, after which you will fail the inspection and will have to pay the fees again. There may or may not be fines involved as well, depending on how severe the consequences could be or if you didn’t get it fixed despite warnings.
In many cases, finding a junction box underneath the drywall or in any other concealed area means that the work was done by an amateur. It works, yes, but just because something works doesn’t mean it’s meant to be. A car can run without a steering wheel as well; but should you ‘drive’ it?
What About Butt Splices for Concealed Joints?
If you look for anything long and hard enough, you will most likely find it. The same is also true for when you need to conceal joints without a junction box. This is known as a butt splice and is actually ‘designed’ to form a tight seal around the joints. Many claim that because the seal creates a vacuum, it can therefore be used under drywall:
Butt splices will set you back about $7 each. You can use one slice per joint. The fact that they create the perfect coating over joints is repeated time and again, but it has never been proven. Having said that, the opposite has yet to be proven as well.
There is an NEC citation, NEC 330.24(b) that suggests that the product is complying for use in electrical systems, but at the same time, there is the NEC Code 300.13 that suggests that nothing of the sorts should be used under drywalls.
If you ask us, we would not recommend using the butt splice under drywall – even though there haven’t been any complaints about the product as of yet. Besides accessibility to make amends, there is a safety hazard to think about.
There is also a financial risk involved. Should there be a fire and the fire department rules that it was an electrical fire that could have been prevented with proper ventilation and/or action from you, or that the hazard could have been detected if the joint was in a junction box, not only will you be subject to a fine, you might also find that your insurance claims might not come through!
So, all in all, we recommend buying a new wire and running it under the drywall to maintain its aesthetic instead of using a junction box and trying to hide it.