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In my house built around ~1970 all ceiling lamps are wired in a way where 120VAC power first enters light fixture and then hot wire proceeds through switch and return back to fixture as load wire. If I understand correctly, then somewhat newer houses built around ~1990 are wired the opposite way where 120VAC power enters first into the switch and then load wire makes a loop through light fixture. Also, there is 3rd option where 12/3 Romex extends neutral to both light switch and light fixture box.

All this time I thought it was a disadvantage to have wiring like mine, because I could not install smart light switches that usually require neutral.

However, it just occurred to me that maybe the future of smart lighting is not smart switches, but rather smart fixtures? Especially for retrofits? If I would switch to smart fixtures instead of smart switches, I could:

  1. eliminate almost all physical light switches in my house (currently I have to upgrade them to CO/ALR rated switches anyway)
  2. simply pull out some old aluminium wiring that runs behind walls as it would not be necessary anymore and my house will have less wiring in attics overall (currently I would have to trace all this wiring and replace splices with AlumiConns)
  3. still be able control my lights with help of voice, motion, phone or with a smart hub touchscreen as I would with smart switch. But I would not be able to have easily accessible physical switch that can turn light on or off.

I am wondering what NEC or any other electrical standards in USA have to say about this? Would it be fine to remove wall light switches altogether if the light fixture can be controlled through WiFi?

  • In the near future you're going to have a battery-operated smart switch (BLE radio or similar and 5-10 year battery life depending on frequency of usage) talking to smart fixture (or multiple fixtures). The switch won't have any wires running to it because it won't need them, and the fixture will be permanently hot (as long as the circuit breaker is on). 3/4/x-way switching is just another configuration option and doesn't require special switches or wiring. – brhans Nov 3 '19 at 23:29
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Lights aren't just for you

Doing this is fine for auxiliary lighting. But there must be a primary light in the room that normal humans can operate without installing an "app". That's right in the building codes, and your occupancy permit will not be issued (or be revoked) if you don't have this. I can only think of 3 ways to operate the primary light:

  • The light is hardwired "on" 24x7
  • The light operates on a motion sensor that actually works
  • The light uses a light switch which is located in the standard location for light switches

This may not have ever occurred to you, but you can walk into almost any room in the US or Canada and you pretty much know where to expect to find the light switch. This is hardwired into your brain at this point. And everyone else's. That is because building codes have standardized the location for those switches.

Part of this is for First Responders. You need the ambulance crew intubating you, not searching the room for the light switch so they can see to work. You want the fire department being able to clear your rooms quickly. And you want the SWAT team able to see you're holding a gaming mouse not a gun.

Part of it is also for guests. A guest confronted with your "to control lights, you need to install an app and use this password" philosophy is far more likely to grope around in the dark and get hurt. Or simply leave the lights on. Governments care about energy efficiency, and they don't like any scheme that burns lights unnecessarily. "Guests" could include domestic servants, aides, or the elderly. All in all, it makes for a very awkward conversation with your guest: "Why can't you just turn lights on like normal people?"

The wiring demands of light switches are actually pretty negligible in the grand scheme of things. I'm sorry you're finding 2-wire "switch loops" frustrating, but there are several workarounds.

Aluminum wire

The problem with aluminum wire is people's overreactions to it, and notably, the obsolescence of those overreactions.

What are we worried about with aluminum wire? To rephrase, what are we worried about with aluminum wire on connection points only rated for copper? Poor connections due to thermal expansion. How does that become a problem? Arcing. And nowadays, we have arc-fault breakers which can detect that.

So that's really the curative; switch the aluminum circuits over to AFCI breakers.

Of course continue with the CO-ALR and Alumiconn conversion, but that takes the urgency out of it.

Keeping in mind that in the LED age, lighting circuits take very little power, and can be consolidated on one breaker.

Most 1970s era panels (Challenger, Murray, Cutler Hammer, BRyant, Square D, GE, Crouse Hinds, T&B) can accept modern AFCI/GFCI breakers. If not, consider either a subpanel (to also be future main panel) or main panel replacement. If the main panel is FPE or Zinsco, make it a priority! While subpaneling, consider future generator or solar interlocks, because this can be added to a subpanel for under $40 (for QO and Siemens), and that sure beats a hokey transfer switch.

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  • Good point about "Light's aren't just for you" to demonstrate why we actually still need light switches in well known locations. The reason I posted my question in the first place about smart fixtures is because I am considering to retrofit a Shelly relay (shelly.cloud/shelly1-open-source) to have smart lighting. Usually one puts them in the lighting switch's box. However, I don't have neutral there. So I am considering to put this relay in light fixture's box. If I want I can leave the switch and it will operate fine, but I believe relay will use low voltage there. – user389238 Nov 6 '19 at 0:36
  • About "Aluminium wire"... The AlumiConns are so relatively expensive that I was just considering to rewire the house to Copper Romex. And at the same time add neutral to light switch boxes to be able to do smart devices. More labor, but cost wise I think it may end up to be the same. – user389238 Nov 6 '19 at 1:34
  • And yes, I have Zinsco. Been on my todo list to upgrade for a long time. Though I am not sure replacing main electrical panel is within my capabilities so I would probably contract someone for that. Was thinking to do that at the same time when I would be ready to upgrade to Solar and possibly off-grid Batteries once it makes more financial sense. – user389238 Nov 6 '19 at 1:52
  • If you are going with modules like these, it moots the switch-loop/smart switch issue. These are able to sit up in the ceiling rose and use the 2-wire switch anyway. Neutral to the module and lamp. Always-hot to the module in two places, and the white of the switch loop. The switched line goes to the "Switch" terminal on this thing. That's what it's for - using a physical switch as a remote. – Harper - Reinstate Monica Nov 6 '19 at 5:13
  • On the Zinsco @HansSolo, push that to the top of the priority list. I'd install a 40 space subpanel right next to it, then move circuits over to it one at a time - aluminum circuits on AFCI. When finally able, have an electrician move the service to the new panel and scrap the Zinsco. – Harper - Reinstate Monica Nov 6 '19 at 5:14
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I fear that my answer will lend itself to opinion, and the question you asked is definitely written so that you are asking for an opinion, but given some important facts, and assumptions you made that are at least in part mistakes; perhaps this will help:

In my house built around ~1970 all ceiling lamps are wired in a way where neutral wire is in light fixture's electrical box and the wall light switches do not have a neutral

Unfortunately, this is true for many many many residences, and fortunately; is no longer allowed. This is written in article 404 of the 2011 NEC.

If I understand correctly, then somewhat newer houses built around ~1990 are wired the opposite way where light fixtures do not have neutral, but the light switches have neutral.

This is not true. A light fixture has to have a neutral. Any circuit in existance needs the supply and return sides. Ground is a safety ground, or ... a safety neutral in essence. But it should never be used like this. If you ever see a fixture that does not have a white neutral, chances are, another wire in there is (and should be identified).

The third option you linked is just a pathing approach. This is nothing more than how electricity got form A to B to C... and most electricians wire a home with some mix of: cost efficiency, use as little copper as possible, and common sense, future expansion and smart routing.

Another thing that exists you did not mention is 3 way switches. This is a little bit more complex, but regarding neutrals, they are all present at each location inside the box.

However, it just occurred to me that maybe the future of smart lighting is not smart switches, but rather smart fixtures? Especially for retrofits?

Have to disagree, but this in itself is an opinion. Smart switches have an advantage. They are "permanent" and separate and take the place of existing switch circuits. Not having them as you later suggest leaves you pretty much up a creek without a paddle when the IOT goes down. Having a hardwired switch has its value for sure. People buy smart outlets/fixtures, and smart bulbs, etc - but then you have one more "wall-wart" (large unsightly blob) that makes your bulb too big, or stops you from using the second plug in an outlet, or stops you from pushing that couch against the wall.

eliminate almost all physical light switches in my house (currently I have to upgrade them to CO/ALR rated switches anyway) simply pull out some old aluminium wiring that runs behind walls as it would not be necessary anymore and my house will have less wiring in attics overall (currently I would have to trace all this wiring and replace splices with AlumiConns) still be able control my lights with help of voice, motion, phone or with a touch on smart hub screen as I would with smart switch. But I would not be able to have easily accessible physical switch that can turn it on or off.

For these points, I've adressed my answer above about value of one smart appliance over the other, but regarding aluminum... You should copper pigtail everything, you should retrofit and remove aluminum whenever the opportunity presents itself. This is a different topic from *smart switch anything. It's just smart! :)

Found this after reading Ed's note *(thanks Ed): Simple notes on room requirements for switches Local-mechanical means has its value. The internet is not perfect, and we all know technology is not either. But since you have a breaker, that technically is a mechanical off switch. Do you really want to have to use it?

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    Fire code requires the local switch / mechanical, for the foreseeable future their will always be a mechanical switch and that switch may also be controlled by a smart device but the mechanical part will be there. 3 ways in the past did not have a neutral at the switches but did have travelers this is part of the update that requires neutrals at at least 1 location on that switched location. And a neutral with a switch leg for a simple on off. – Ed Beal Nov 2 '19 at 23:47
  • Thanks @EdBeal, revised. Didn't have the NEC memorized but added a link to a site with a decent relevant summary. – noybman Nov 2 '19 at 23:57
  • @EdBeal, I think your comment was the answer I was looking for. So Fire Code requires to have mechanical switch for light fixtures, but the circuit breaker qualifies as one? So smart fixture without a wall-switch would be ok? – user389238 Nov 3 '19 at 0:40
  • @HanSolo, no you cant ignore the need for a switch, Ed's note provoked me to look further, and I posted the link that gets into the rules for each room, which requires a switch. We can probably find the NEC paragraph number(s) – noybman Nov 3 '19 at 1:00
  • It is true each room requires a device operated by a switch, the device can be a standard receptacle or a light fixture but each room must have 1. I did not catch the last part until rereading the post probably for the 3rd time , sorry I was slow on what your focus was , I focused on the start of the question the first few times. – Ed Beal Nov 3 '19 at 1:53
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I'm not concerned about the neutral problem (new houses have them, old houses are gradually being upgraded, and there are some smart switches that can work without a neutral).

Easy Access

But I am very concerned about ease of access when things go wrong. And the more complex they are (microcontrollers instead of a simple switch), the more likely something will eventually go wrong. (And even simple switches can go bad too).

With the fancy electronics incorporated into switches, a problem with a switch means replacing the switch, which will always be within reach as otherwise it isn't a very useful switch. But fixtures are typically up in a ceiling, requiring a ladder to reach them and often much harder to open up than the typical two screws on a switch.

Number of Units == Cost

A single switch (or pair of switches - e.g., 3-way) can control many fixtures. If each fixture has its own smarts, the cost will likely be more than adding the smarts to the switches.

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  • Good point about one switch being able to control multiple fixtures - in those cases it may be more cost effective to get just 1 switch. Although, in my house one switch always controls exactly 1 fixture. So I actually would save on wiring by having smart fixture which reduces the loop from switch to fixture. – user389238 Nov 3 '19 at 0:10
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    Great point about "one switch to rule them all" ugh, imagine can lights, you have 9.... buy 9 fixtures, or one switch? Even better, the smart 3ways, have the master $40 switch, and then the $9 children. So you can have the best of all three worlds. (Still need a neutral). Your answer solidly removes the "opinion" part. – noybman Nov 3 '19 at 0:11
  • Although, there is nothing preventing to put one smart fixture that rules the all other 9 dumb fixtures that are daisy chained together? It would be kinda like wall smart switch hidden in light fixture. – user389238 Nov 3 '19 at 0:33
  • @HansSolo Except that normally fixtures are wired parallel. To have one control another they would have to be wired serial. Which could really confuse things for the next owner. – manassehkatz-Moving 2 Codidact Nov 3 '19 at 0:36
  • Maybe I did not use the term "daisy chain" correctly. I meant that out of the first smart light fixture there would be a load wire coming out that remaining 9 dumb fixtures would in parallel connect to. Just like out of a wall switch. And then neutral form each "dumb fixture" would either return back to the "smart fixture" or just pigtail before it. – user389238 Nov 3 '19 at 1:00
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Code has changed a while back and requires a neutral in the switch box. , code has always required the hot to be switched , so your understanding is a little off (with the exception of a California 3 way old school method not code compliant today) As far as smart fixtures the smarts are currently built into some lamps / bulbs not the fixture itself. Their are smart switches that can operate without a neutral but these usually do not play well with LED lighting. Their are switch designs that do not need a neutral and will work with LED’s so what’s the future? I hope Nikola Tesla’s wireless energy transfer but only time will tell. I hope you caught the part that a mechanical switch is and will be required to override the WiFi in case of an emergency.

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  • I did not mean to make a newbie mistake that neutral is ever switched, but after rereading my question it seems that is exactly what I did. I meant this topology - youtu.be/CaaLw01fMo8?t=111 Will update my question. – user389238 Nov 3 '19 at 0:18

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