These electrical outlets are for the truly aesthetic-obsessed (which I am).
I only have them in the areas of my apartment where an outlet must exist and cannot be hidden. All other outlets in the apartment have been moved behind furniture.
I like my technology invisible. 
Perhaps you can put a Zigbee plug into an outlet hidden behind furniture … whatever is closest to the dead zone. Even if it’s not close, it’s better than nothing and inexpensive.
The problem is the apartment is sorta long and down the middle of it there is one pretty outlet and nothing else. And that’s the dead zone.
The solution I’ve landed on is adding an outlet in the closet in that hallway.
For my own education, what type of apartment complex allows its tenants to modify their dwelling’s electrical system?
Or is a condominium?
It’s a condo which I own here in NYC. By law I cannot modify anything myself. I have to hire a licensed electrician.
When in doubt, add more Zigbee Router devices 
When it comes to Zigbee networking mesh it is almost always best to just have many “good” Zigbee Router devices than only a few “great” Zigbee Router devices, but still, having a few “known great” dedicated Zigbee Router devices placed in strategic location can be a very good idea, and that is something that I sometimes recommend to new Zigbee users that plan to start with a few devices before they add more, and if they do not get will not get enough coverage or range needed for their entire home.
There are also some specific Zigbee Router product tips about that here → Zigbee networks: how to guide for avoiding interference + optimize using Zigbee Router devices (repeaters/extenders) to get a stable mesh network with best possible range and coverage
Personally I can stongly recommend convert a few of ITead’s “Sonoff Zigbee 3.0 USB Dongle Plus V2” (model “ZBDongle-E” based on Silicon Labs EFR32MG21) into dedicated Zigbee signal repeater / Zigbee range extenders by flashing them with Zigbee Router firmware and powering them with a simply USB-chargers. While maybe not the prettiest solution to look at, if you make sure they are permanently powered then joining/pairing three or more to your Zigbee network and spreading them around in your home will create an extremely stable backbone in your Zigbee network.
Action: Buy a few known good dedicated Zigbee Router products and place them strategically as Zigbee repeaters. Personally, I suggest buying and adding at least three such devices.
Tips
That is actually not entirely true. All types and models of Zigbee Router devices are definitely not created equal. How they perfom will depends on exactly what antenna type and design, Zigbee radio chip model used, Zigbee stack revision, Zigbee firmware version and configuration.
Most commercial mains-powered Zigbee Router devices will not have a radio chip or firmware configuration that offers the same performance as a DIY Zigbee Router made from a convertered Zigbee Coordinaor dongle with external antenna. Older chips also ussually have worse performace than newer chips.
Yes it is true that there are government regulations for the maximum transmit power-level for low-powered devices (around 14+ dBM in Europe and around 20+ dBM in North America), …but that does not mean that everyone configure their to use the maximum (fact is that most devices that ship use much lower transmit power than maximum allowed), nor that everyone follows the regulations.
Regardless of avove, relocating your Zigbee Coordinator dongle will be among the most important steps.
Begin by relocating your Zigbee Coordinator dongle by using a longer (shielded) USB extension cable and make sure connect it to a USB 2.0 port (and not a USB 3.0 port) or specifically use a USB 2.0 cable. EMI/RMI/EMF interference can easily kill signal reception for the Zigbee Coordinator, which is why it is so extremely important to keep it away from all possible sources of interference and make sure that the radio frequency range of your WiFi channel(s) do not overlap/conflict with the radio frequency range of your Zigbee channel. Again, that and more is covered here → Zigbee networks: how to guide for avoiding interference + optimize using Zigbee Router devices (repeaters/extenders) to get a stable mesh network with best possible range and coverage
There are also some specific tips about that there, including how to convert an Ethernet cable to make a very long (but passive/dumb) USB extension cable by buying RJ45 conversion adapters → Zigbee networks: how to guide for avoiding interference + optimize using Zigbee Router devices (repeaters/extenders) to get a stable mesh network with best possible range and coverage
You could do that with “zha-toolkit” but understand that in your situation there is no point with a before picture, that would just be a waste of time at for you right now in your current situation. You first first need to take action to sort out all low-hanging-fruit issues before troubleshoot any deeper → Zigbee networks: how to guide for avoiding interference + optimize using Zigbee Router devices (repeaters/extenders) to get a stable mesh network with best possible range and coverage
Also understand reported RSSI and LQI values can sometimes be arbitrary and not always useful, read:
and
That is correct. There are no such things. Time to add that to docs → Mention another Zigbee limitation in ZHA docs by Hedda · Pull Request #33417 · home-assistant/home-assistant.io · GitHub
…and what do you know, that is also covered here → Zigbee networks: how to guide for avoiding interference + optimize using Zigbee Router devices (repeaters/extenders) to get a stable mesh network with best possible range and coverage
I worte that guide so that I would not have to sound like broken record that repeats itself 
Here’s a little before and after of the changes I’ve made. Everything will be green except the furthest door once I replace the aqara door sensors (which refuse to talk to the sonoff router).
This is more like how it should look when you have routing devices setup in the mesh:
ignore the red one in this one as that is an aqara t2 relay I am waiting for an electrician to install but have it already paired and setup.
That does NOT look good, there does not look to be any mesh networking going on at all. You should add many more Zigbee Router devices. Yeah I going to once again refer you to the read and try to follow the best practice this here → Zigbee networks: how to guide for avoiding interference + optimize using Zigbee Router devices (repeaters/extenders) to get a stable mesh network with best possible range and coverage
FYI, Aqara’s Zigbee devices are infamous for not automatically moving to better/closer Zigbee Router devices on their own, it is well known within the community that you will need to manually re-pair/re-join Aqara devices after you add more Zigbee Router devices.
Most other Zigbee devices revealuate neiboring Zigbee Router devices and usually automatically move around once every 24-hours if there are any better/closer Zigbee devices available.
I’ve actually repaired the aqara sensors multiple times to the sonoff router and they just go straight back to the coordinator. Even though the router is much closer. I’ve already ordered some sonoff door sensors to replace them.
The topology I am going for is essentially a linear backbone based on sonoff routers with a SkyConnect coordinator. Assuming those devices are robust (which is perhaps a poor assumption) what is the value of adding more routers to get some meshing going?
Others have mentioned powered sockets, and the Ikea Tradfi smart bulbs (mine are gu10) work as relays okay. I’ve got three in my house and they’ve definitely boosted signal everywhere.
Did I actually say that again? (Too many Z devices and not enough Z’s here).
There’s a reason you will never see them in a home improvement store:
Code only requires access to the connections. If the pigtail of wire from the box is long enough to be accessible with the socket extracted, then I don’t see a code problem here.
I’ll agree that it would be a shame to hide such expensive artwork by plugging something into them. (snark). Don’t you have any outlets in closets where you could plug in one of these ugly routers?
From my experience, (I was an electrician in the prior century), local codes have always allowed homeowners to do their own electrical work as long as the appropriate permits and inspections are done. Unless, in most communities, the home is a multi-family building like a condo or apartment. This is the law in NYC.
Totally agree, if the plugs are too fancy to have anything plugged in, why have them at all?
It just occurred to me that the OP said that he had “few outlets”. The NEC (used in NYC) requires that no point on a wall at the floor can be more than 6 ft from an outlet. (This is why appliances, lamps, etc come with a six-ft power cord). So outlets will be no more than 12 ft apart. Also, any wall space with a width of 2 ft or more must have an outlet. Kitchen outlets have to be no more than 48-inches apart. (Which explains why countertop appliances like a toaster have a 2-ft power cord).
If it were a rental unit (what we locally refer to as “apartment”), normally the landlord does not permit the tenant to perform significant modifications to the dwelling, such as adding a new outlet. That’s why I was curious to know what kind of “apartment” allows for that but it’s a condo (ownership vs rental).
In my province, you’re obliged to hire an electrician to perform electrical work. However, you can hire one to inspect work that has been performed (by a non-electrician). About a year ago I helped my brother-in-law add a new circuit for an EVSE in his garage and he then had it blessed by a master electrician. In this case, no permit was needed to perform the initial work.
As for the eye-watering price of 22 System’s products, you’re right, that’ll keep it off the shelves of a home reno store. I thought Legrand’s adorne outlets were spendy but these things are easily 100 times the cost of a vanilla Decora outlet.
For temporary usage like an iron or a vacuum or a mixer. But nothing stays permanently plugged into them.
Right. We’re dealing with a hallway with a ton of doors on it. So there is only space for one outlet. And that outlet is the pretty outlet. Thus me adding an outlet in one of the closets.
This is why I suggested to get those specific ones setup with a relay behind them if there is room, you keep the look and you gain a relay to extend the mesh as well as monitor power usage with the socket of anything plugged in at the time.
