Can I cap a hot wire and leave it in a junction box above ceiling fan?
Specifically:
Is it safe and to code to cap a hot line and leave it in a junction box? I think this is SOP, but want to double-check.
If so, any reason not to do this for a ceiling fan due to vibration, etc.?
Background:
I have a standard combo ceiling fan and lights and a pair of wall switches (one for the fan and one for the lights). I want to add a wireless receiver in the fan’s canopy. The receiver can independently control both the fan and the lights, but I want to keep the light solely controlled by the existing wall switch.
I can accomplish this by keeping the receiver’s light output unconnected, capping it, and putting it in the junction box above the fan. By default, the output is not hot. However, if the user presses the light button on the wireless remote, it will make the line hot.
To start, I’m an EE not an electrician. Not familiar with the details of code but a decent idea of what is safe.
Wire nuts are made to connect a specific number of wires of a specific size. If you get that wrong, it could fall off leaving an exposed end of a wire. You could use a short length of wire. Strip both ends, and fold it in half. This gives you three ends of wires. Insert them all into the wire nut and twist it normally.
Okay all you electricians out there, tell us why this is crazy.
Also not an electrician only an EE; living in Germany not North America to boot. In our household I use Wago 221 series splicing connectors with lever to connect wires rather than US style wire nuts (which are not used or permissible in Germany). To insulate a hot wire end I use a 2-terminal Wago with the second terminal unused. I‘d very much advise against insulating a hot wire end with tape, or using any type of screw terminal.
Using a wire nut to cap a single hot wire is done all the time by electricians in the US. The standard wire nuts an electrician would have on hand will take a single 14 or 12 AWG wire. Make sure you actually strip back the insulation so the wire nut bites down on real copper (obviously not so much insulation that there is exposed copper outside the wire nut body). Lazy electricians will just shove the insulated wire in a wire nut - this is also commonly done, but in this case the wire nut is gripping the insulation not the copper so it won’t hold as well. I’ve also seen this done on wires that are typically not energized (e.g. neutral, ground, abandoned conductors), just as a backstop so that wire doesn’t end up poking something else and becoming energized in the box.
If the wire nut is actually too large to take a single wire, the normal trick is to strip back a double length of exposed copper, bend that in half to form a double-thickness (ideally twisting to form one solid piece), and put the wire nut on that. If even that is too small, you’ve got the wrong size wire nut.