New to home automation -- How limited am I by old wiring?

When it comes to lighting I don’t really care about being able to change the colors, but being able to dim the brightness is important.

From what I’ve read, having a Switch will allow you to control the lights via the switch and by voice command/app, which would be ideal in case a guest turns the light off.

I am in the US and don’t quote me on this, but I believe my wiring is knob and tube. I know it’s the original wiring that came with the house and the house was built in the 50s… not sure if that helps at all.

It’s been several months since the inspection was done so I’d need to look up the official documentation.

Let us hope it’s not knob and tube: that’s going to really limit your choices and you may have to just go with smart bulbs. But knob and tube (k&t) would be unusual in a house built after 1940.

(Oh, one of the first things you’re going to learn about home automation is that tiny details can matter a whole lot. :sunglasses: You’re going to need to look things up and get exact model numbers and exact specifications and read manuals in order to make the right device choices. It’s fine if you don’t at first, just be prepared for people in the forum to ask for more details if you don’t have them right away.)

Both smart bulbs and smart switches can be controlled by voice, and both can dim depending on the exact model selected, and there are lots of ways to address the issue of not turning a smart bulb off at the switch. So that one is a solvable problem. :sunglasses:

I do research thoroughly before making a purchase, although I may not have the mindset initially to list model numbers and whatnot.

I looked up my inspection is this is all I could find about the outlets not being grounded:

“ Open ground (or 2-wire) outlets present. This means that the 3rd (round) part of an appliance plug is not getting ground protection. This may be a concern with items such as computers and electronic devices. Noted at about 80% of the homes receptacles”

Pretty much every outlet has three holes, but a few only have two. I do have GFCI outlets in the bathrooms and kitchen.

In regards to the electrical being up the code, the inspector did say it was to code, but recommended having it looked at by an electrician. I have the seller bring out an electrician to look at my panels and several outlets that were not functional and they fixed the outlets (two of which were GFCI) and signed off on the panels being very old, but up to code.

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OK, what they probably did was replace the ungrounded receptacles (the two hole ones) with GFCI outlets, leaving an open ground condition. The GFCI in the outlet itself will protect a human from shorts, but would not protect against surges, which is why you’re supposed to have the extra sticker that it’s “not grounded for equipment.” Some of the receptacles maybe grounded to the box itself, in older homes that was a fairly common method. But what this all means is that you are not going to be able to replace your receptacles with smart receptacles. You should be able to use plug-in modules, which we call “pocket sockets” in the forum, just to distinguish them from the in wall receptacles.

@Navat604 or one of the other electrical experts in the community might be able to say more.

As far as the light switches, we still need to know which of the three it is.

Is there a way for me to indentify myself which of the 3 it is?

Also, I was reading the link you provided in your previous post and the smart switch cover seems like a viable option for me. Do those simply just get applied over the already installed light switch or how do they work exactly?

Thanks again for all your help :call_me_hand:t2:

If you have knob and tube wiring, In most jurisdictions it should’ve been noted on the inspector’s report, as many insurance companies will either charge you more or not insure a home with knob and tube wiring at all as it can become a fire hazard as it ages.

It’s not against code to have it in most US jurisdictions but you should certainly be aware that you do and probably have it inspected annually

But again, it would be rare to find it in a home that was built after 1940. But not impossible.

As far as the issue of neutrals at the switchbox, You may find that you have them at some switchboxes and not others. This is really common in a US home that was built in the 1950s. The reason is that over time people will tend to upgrade the electrical system one branch at a time or even one room at a time and you can end up with differing configurations. You’ve already seen this in your own house because you have some in wall receptacles that don’t have the grounding hole. So it’s probable that some were replaced but rather than doing the whole house at once, the homeowner just did them in the areas where they were immediately needed.

The following is an article from Insteon on how to tell whether you have neutral wires in the switchbox. The Insteon devices are not compatible with smartthings, but the article itself is good on the wiring part. We do need to say upfront, though, that US code does not mandate colors for most wires, and people can and do use any color, particularly if it’s near the end of the day and there’s only one spool left in the toolbox. So you might open the switchbox and see all black wires or even all red wires rather than one black, one white, and one red. That’s why the only way to really be sure is to use a line testing tool.

Also, about now I usually mention that if you live near a Home Depot many have a free course on how to install a light switch. Although it will not typically cover smart switches, it’s a very good way to get familiar with what the wiring will look like and how to use the simple tools for mapping your circuits. So it can be worth checking out If you like having that level of knowledge. Or, of course, you could always pay an electrician. :sunglasses:

No Neutral? The Lutron Option

If your switch boxes do not have neutrals, the easiest solution is just to use Lutron Caseta switches. Lutron Is an engineering company that only focuses on lighting. They hold a bunch of patents including one on a method for using a smart switch when there is no neutral wire. There is an official smartthings/Lutron integration which works well, although you do need to also have the Lutron SmartBridge Device to make it work.

These are very nice switches and an excellent retrofit solution for older homes. I use them in my own house Which was built in 1955.

There are a few Z wave switch models which don’t require a neutral wire, but they only work with incandescent bulbs and most people prefer LEDs or CFL’s these days.

You can get a Lutron starter kit with two master switches, two auxiliary pico’s (to set up a 3 way), and the bridge for right around $160. One bridge can support up to 50 Lutron devices.

So zwave switches will probably cost less Per switch, and you won’t need an extra bridge device, but they do generally require a neutral wire. So it’s just good to know that the Lutron is an option if you need it. :sunglasses:

Back to Smart Bulbs

One other alternative, as you noted, is a smart bulb and a smart switch cover. The smart switch covers come in a couple of different styles, But, yes, most of them just fit right over the existing wall switch.

The other very popular alternative is to get a battery operated device and either put a box cover over the existing switch and then put the battery operated device on top or put the battery operated device next to the original switch and just use a childlock on your original switch.

The following FAQ lists most of the devices that can work in this fashion. Some of the individual entries are battery powered and some are mains powered so read the entries carefully. There’s generally just one entry for each device and it should include a link to a discussion thread about that, so if you do have follow-up questions on any of the individual devices go to the discussion thread and ask the question there.


Before you make any decisions or buy any devices, determine for certain if your house has a grounded electrical panel and grounds for the branch circuits. If it doesn’t have ground wires in the box, I do not recommend installing any smart switches or plugs. You will either get flakey operation or it won’t work at all.

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Sorry to bring back an inactive thread, but I finally got around to pulling out my switch to look at the wiring and there are two wires (black and red) with no ground. Am I SOL?

Depends which devices you’re interested in using. You’re limited but not screwed.

JD’s post above goes through some of the options if you have no neutrals.

You’d have to run a ground yourself, unfortunately. Would it be possible to drill up from the basement and run a separate ground wire to each box?

@marktheknife there’s clearly neutrals, just no grounds.

Sorry missed the last picture.

Is that a metal switch box? If the conduit is metal, then that may be your ground.

That’s how my switch boxes are. Check with a multimeter, one terminal on the hot wire and the other on the box itself, if it reads 120V then the box is grounded.

It’s not conduit though. That’s just a flex connector with an old paper wrapped romex.

Personally I don’t think it’s easy to tell based on just those few pictures. It kind of looks like some of my boxes, as I mentioned. I’m not an expert though.

I’m a commercial electrician. Conduits won’t have wires with paper sheaths in them, only bare separate wires (unless someone’s run a romex inside the conduit, but that’s less likely)

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Thank you for clarifying. It would seem that’s how my switches were wired. :man_shrugging:

The other reason I doubt it’s conduit is because it’s coming out the back of the box. A 1/2" conduit would need at least 6" radius, plus the box depth, so it’d have to be backing onto another wall or have a hollow spot behind. More likely it’s a 90 degree wire connector.$pipGallery$&id=jdvSv3&fmt=jpg&fit=constrain,1&wid=500&hei=400

I guess the only way to be sure is to check if the box is grounded with a multimeter?

Yep. Can just check from neutral to box for continuity/resistance. It’ll be open if not grounded, and a few ohms if it is.

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Yeah so I stay away from electricity if I can help it, so I have no idea what any of that fancy lingo means haha… I can say however I have no basement and on this specific switch the wall is cinder block so I can’t exactly cut into the wall.

So, the pictures I took has 3 separate switches… the one I focused on has a black and red wire, the other two have black and white wiring.

Is there something else I can take a picture of or is it pretty clear my wiring is too archaic for your standard smart switch?

Thanks for your help guys.

If, as mark supposed, your junction box is fed with conduit (a possibility, given it’s cinderblock) then the ground would be the conduit itself and no additional wire is necessary. Any chance you own an ohm-meter or multi-meter?