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.
Yep, not a problem at all. I also agree that you should strip away a little bit of insulation, so that the metal threads inside the wire nut thread onto the copper wire. If the wire nut is too big, use a smaller one.
I’m in the process of wiring our barn. I told my (electrician) cousin that I plan to use Ideal push-in connectors (similar to Wago splicing connectors) since they’re so much easier to use vs. wire nuts. He told me he only uses those for lighting circuits; never for outlets. So I am using wire nuts for outlets.
Yes, done all the time (and I am indeed an electrical contractor). In a commercial installation, for example, you may have the main electrical contractor provide a circuit for a piece of equipment which will be installed later. A good example of this is a fire alarm system. The contractor will install a dedicated circuit breaker in the service panel, run a short piece of conduit out to a junction box, pull conductors to the box, and install wire nuts (or similar) on the three branch circuit conductors intended for future use. Of course, the breaker and box have to be identified for use for the fire alarm system.
And I’m just about to extend a light switch circuit in my kitchen from one box to another. I will be using some 14/3 NM cable (e.g., Romex), but will only need two of the conductors. I will place wire nuts on each end of the unused conductor because we don’t want unidentified conductors in a box that aren’t terminated or insulated. It makes us nervous.
Cable is expensive and I happen to have about 10" of 14/3 lying around. Also, it gives me the proper colors for a return to a light fixture. It is the white wire that will be capped and available as the (now required) neutral at the box. (So I guess I lied earlier. The neutral will only be capped at the new switch, not both ends.)
On paper those push-in connectors are fine, but many electricians prefer not to use them at all, or like your cousin, only for lower power loads like lighting. They’re faster and take up less space in a crowded junction box, but aren’t as reliable, more difficult to rework, etc. Related debates: backstab vs screw receptacle connections, daisy-chaining vs pigtails, scotchlok vs splicing, stab-in vs bolt-on breakers, bare stranded wire vs ferrules, ring vs spade terminals …
Current code in Canada and the US requires a neutral at all switches to facilitate the use of modern smart switches. The day of using 14/2 for a switch loop and remarking the neutral is at an end.
That’s fine; it’s done all the time by electricians.
Just be sure that the wire nut is tightly connected. Best to downsize the connector to a yellow or orange one, that is smaller and will be tighter.