"It's a violation of NEC to make a splice in even low voltage applications outside of a junction box? Really? Then I've never seen a correctly wired furnace's call for heat/call for cold lines."
Each country/state/municipality has its own code governing requirements. The NEC is the bible for the US and it is either followed verbatim, or superseded by stricter / unique local codes. I have not ever seen where local code is more ‘lenient’, but usually has more stringent requirements. And then there is the inspector who interprets code, which varies greatly. The inspector has the final say unless you want to take his ruling to the local building department for arbitration.
An in wall or underground splice is OK, as long as it’s done per the NEC and local code requirements. 99 times out of 100, wire nuts do not qualify for these situations, regardless of voltage as they do have a large potential to come off or not provide adequate binding of conductors. Even mili-amp circuits have the potential to be an ignition source (class one / div one for example where mili amp control circuits run throughout PSM covered industrial process areas). After time, studs get very, very dry and damn near anything can set them off, regardless of voltage. Ever respond to a trailer house fire? Doesn’t take long for them to go up in smoke.
Whenever a spice is done that will not be accessible, it MUST be done per code requirements which will mean it has to be done in a J-box or panel that is either non conductive or grounded. If it is accessible, wire nuts will usually suffice, but again, local code dictates that requirement.
With in wall wiring, J-boxe splices are considered ‘accessible’, provided that they are not covered by wall board which would mean that you need to use a J-box and cover plate.
I’m not advocating that anyone perform any kind of in wall splice without doing it in an approved J-box or termination panel, PER CODE. But, if one just insists on shortcutting and ignoring that advice, the splice technique I recommend will be the safest bet and I’d rather suggest that someone do that, than simply twisting a couple wire nuts on it. I can at least have a guilt free conscience that I attempted to steer someone in the right direction and their home stands a slightly better chance of not going up in flames.
I’m a volunteer fire fighter and industrial fire brigade member. I’ve seen a lot of fire and smoke for stupid assed reasons that were TOTALLY avoidable.
Disclaimer: I do not carry a current electrical fitness card and am not licensed or qualified to give any electrical wiring advice. Always consult with a licensed electrician and take internet suggestions/advise with caution.
