Handling an overloaded Circuit Breaker with Home Automation

Background:

 Every year there are popular buzz words: Hydrogen power, Green Energy, 4G, 5G, Smart Home, Artifical Intelligence, Virtual Reality, Intenet of Things, etc. - but half of the time there is no real benefit to the consumer, or the benefit takes a lot of cost and effort to reach.

As an example, 5G demployment benefits the telephone companies much more than consumers.  On a decent LTE connection, a consumer with a 30 GB/month plan could easily use up their entire allotment in less than a day - so why do we need 5G?  It's not because 4G isn't fast enough for most uses, it's because phone companies want to be able to server more people with more efficient use of the spectrum.  

Likewise, "artificial intelligence" is used to mean practically everything and anything, when in fact most artifical intelligence solutions aren't smart at all in terms of what we might call "intellegent", and they certainly aren't sentient.  Case in point, ChatGPT is at the end of the day just mindless a collector and summarizer of information.  It's impressive that it can synthesuze the collected information into new sentences and paragraphs, but at the end of the day, it just parrots what ir finds on the web, without vetitng it or verifying it against reality - or even logic.  

On to "home automation" - Simple timers and X10 controllers have been around since at least the 80s, and WiFi controlled switches have probably been around since the late 90s - but truely cost effective smart home devices have only emerged in the last 10 years or so.  

There are still teething issues, such as competing standards for controlling and monitoring such devices, imcompatible apps, lack of flexibility in how to link things together, etc. - but it is slowly getting better.

Smart speakers came on the scene a few years ago with a bang, and then slowly died down to a quiet background whisper.  From the consumer side, it was super cool that you could say "Okay Google, turn on my Light", or "Siri, what time is it?", ot "Alexa, tell me what the weather is like outside." - but for most people, that's actually all these devices are good for.  

Even when connected to deviced like remote controlled outlets, there is still only a limited amout of usefulness, because most modern devices won't simply run when power is applied to the cord, but they have "soft" power control as well.  There are IR controllers like the SwitchBot Hub, which can be used to control things like an air conditioner or TV, and there are plenty of "smart devices" which can be controlled by a smart app or similar - but these apps often live in their own universe and can't be connected flexibly & easily to anything else.

Our Challenge:

The house i live at most of the time has a very odd circuit setup. 

There are two bedrooms, a living room/kitchen, a basement, bath room, toilet room, two hallways, and an attic.  Like any house, there are various circuits, each of which has a circuit breaker.  

The breakdown of the circuits is where things get problematic.  The kitchen/livingroom, basement, bath room, toilet room, and one hallway are all on one single breaker.  (The only exception to this is the living room air conditioner, which is on a separate breaker).  

What this means is that if someone decided to use a hair dryer or curling iron in the bathroom at the same time as the dishwasher in the kitchen, they will blow the breaker.  This applies equally for using the dishwasher and coffee machine (both in the kitchen) at the same time, the rice cooker and the coffee machine at the same time, etc.  

This means that the breaker may trip several times per week even under normal usage.  

This seems like a really poor design choice to me, but having the power suddenly cut out is even worse when using modern devices like computers, where you might lose hours of valuable work and damage sensitive electronics.  

To make matters worse, I want to actually use the basement as a real room.  It has one outlet (intended for the washing machine), and one light fixture in the middle of the room - so I can see why they didn't feel the need to run a separate circuit for this room.  Although I run extension cords or even have additional outlets installed, none of that will change the fact that it is all on a single circuit - a single circuit shared with the toilet, bath, kitchen, and living rooms (plus a hallway).  

Using lights, a computer, etc., in the basement adds to the "normal" load, meaning that a "heavy" load appliance needs to draw even less to trip the circuit.  In the worst case, a single high load appliance along with multiple medium load devices could cause a trip - but usually it takes two high oad devices.  Sadly, the basement won't be livable wihthout an air conditioner, and that is at least a medium load device.

A little more about the loads:

The circuit is a 20 amp circuit, at 100v, which means it can theoretically handle 2000 watts.  Some high wattage devices draw more than half of that, so in that kind of case, only a maximum of one high load device could be used.  For example, if a hair dryer takes 1200 watts, and the dish washer takes 1300 watts, then only one can be used at a time even if they are the only things on the circuit.  

Some devices may takes less than that, for example, 300-800 watts, and may cycle intermittently, but if several devices cycle at the same time, this can still cause the breaker to trip.  For example, the water cooler and refridgerators both have compressors that occasionally come on, and the toilet has a heated seat that warms as you enter the room (along with the light coming on).  If the water cooler and refridgerator both happen to cycle on simultaneously just as you enter the bathroom and the air conditioner is on.. bam! the breaker trips - even though you were only using one "high power" device.  A "slow blow" breaker may or may not solve this issue, depending on the duration of the surges.  

Obviously one "solution" would be to put in a higher value circuit breaker, but that would mean the wires would most likely be operating above rating.  The insulation might break down, or perhaps even cause a fire.  

A proper, legal, solution would be to replace all of the wiring with thicker wiring and put in a higher value breaker, or better yet simply split each room into a separate circuit.  Sadly, this would probably require ripping up the wall and cost a good deal of money.  

My Fantasy

A while back I had a fantasy that devices should be smart, and know what kind of circuit they are connected to.  For example, they would communicate over the power line via some protocol like X10 to the circuit breaker and each other to make sure the breaker is not overloaded.  Devices could be set to high or low priority, so that when you use a high priority device, it checks the remaining overhead, and if activating would exceed the circuit limit (and trip the breaker), then the device will signal to lower priority devices to pause.  

For example, when I turn on the coffee maker, if could find out it is on a 20 amp circuit, of which 16 amps are being used.  Since the coffee maker knows it is an 8 amp device while actually making coffee, it signals to other devices on the circuit to pause.  The dishwasher and air conditioner volunteer to pause, and the coffee maker checks the breaker again, finding out this time that there are 8 amps being used, and 12 amps of overhead.  It proceeds to brew the coffee, and then signals to the other devices that it is okay to unpause.  Even without this signal, the other devices would randomly start to check back with the circuit breaker every few minutes.  If more than 10 minutes passes without any signal from the high priority devices, and there is enough headroom, then the low priority devices such as the dishwasher continue.  

In my scenario, high priority devices would include devices like the microwave oven, hair dryer, and coffee maker, while lower priority devices might include things like the dish washer, water cooler, refridgerator, air conditioner, etc.  Things that might need to be on, but they can be paused for 10 minutes or so with no major ill effect.  

The advantages to having the devices "know" they needed to lower power consumption is that they could do it in a smart way.  For example, the dish washer could simply "pause", and then "resume", without needing to start a new cycle again.  Likewise, something like a rice cooker could be told to stop warming the rice for a few minutes, and then told that it is okay to warm the rice again - whereas pulling the plug would probably reset the device.  

Sadly, although "smart breakers" are actually a thing, smart devices that communicate with them and the protocol to ask for extra power or volunteer to switch to low power mode temporarily is still immaginary.  

The Manual Solution

Before we discuss automation, let's think about how this situation can be solved manually.  

Basically: Identify which devices are "high power" devices, and make sure you (or anyone else) isn't using any of the other high power devices before you turn such a device on.  If another such device is on, turn it off.

In practice, this is difficult, since I have one circuit covering five rooms and one hallway.  For example, every time I want to make a coffee, I should go into the basement and turn off the air conditioner, go up and make my coffee, turn of the coffee maker, and then go back downstairs to turn on the AC again.  

Another practical difficulty is that although I personally think it's obvious which devices are high wattage, some household members might not be as...  savvy.  

One final particularly annoying problem is that for some devices, it is difficult to tell when they are "done".  For example, the coffee maker seems "done" when it's finished brewing my coffee, but in reality it decides to shut down about an hour after the last use, and it does a self-cleaning phase during the shut down process which uses  enough electricity to trip the breaker if, for example, the dishwasher is running at the time.  It's not unreasonable that people might not remember this rather obscure fact. For the dishwasher, it goes into a drying mode when it's completed washing dishes.  It sounds quiet, but it is actually still using electricity, so one might not notice.  

The Realistic Solution: The Smart Home

It recently occured to me that the SwitchBot Smart Plugs can support up to 1300 or 1500 watts (Depending on the model) continuously.  Besides that, the app has a "scene" mode, where multiple devices can be controlled at once.  Although this was certainly intended primarily for lighting, it can be used for anything.

It occured to me that all I need to do is make several "scenes" where each turns on one device, and turns off several other devices.

For example:

• A. Normal Scene
1. Basement AC: On
2. Coffee Maker: Off
3. Dishwasher: Off 
• B. Coffee Scene
1. Basement AC: Off
2. Coffee Maker: On
3. Dishwasher: Off
• C. Dish Washing Scene
1. Basement AC: Off
2. Coffee Maker: Off
3. Dish Washer: On

Then, by manually selecting a scene using the application on my phone, one of the devices can be switched on, and the two other devices will be simultaneously switched off.  

For example, in the morning when I want to make coffee, I might turn on the coffee maker by switching to the "coffee" scene manually (or automatically via timer).  This would turn off the air conditioner, and cut power to the dish washer.  

When I am done, I turn the coffee maker off (to let it clean properly) and switch the scene back to "normal" to cut power to the coffee maker and power up the AC.  Assuming I forgot to properly power down the coffee maker, it will just receive a rude power cut instead.  

If I want to use the dish washer, then I likewise change the scene to "Dish Washing", which will cut off power to the coffee machine and turn off the AC.  I usually wash dishes in the evening, so it's not likely the coffee maker would be on anyway.  

When The dishwasher is done, I would then activate the "normal" scene again in order to cut power to the AC and make sure that the basement AC is cooling again.  

Sure, I might need to add a few more devices, such as hair irons or waffle irons, but the concept can easily be expanded.   

The main issue with this arrangement is that there doesn't seem at first to be an easy way to get back to the "default" scene.  For example, you're not making coffee or washing dishes, but the AC is still off in the basement because you forgot to change the scene back to "normal".   

Ideally, there would be a default scene and a "scene timeout" where you could set some scenes to expire an hour after they have been set, etc. - but sadly that doesn't seem to be a supported feature.  

There are a few ways around this.

One way is to use the geofencing feature to activate a scene when I am away from home, or when I arrive home.  

This might not make sense in all cases, especially if there are multiple people, or conditions that don't depend on your location.  

For example: I might decide that I want the AC to be triggered when I leave the house, since i want to keep the room cool for my pets even when I am not home, and I am obviously don't plan on making any coffee while I am out - but the same logic doesn't hold for the dishwasher.  After all, perhaps I put the dishes in the dishwasher and started it before I left the house in order to make sure they get washed while I am away.  

Again, this breaks down if other people might be doing things while I am away.

Another way is to use a timer.  There are at least a few times of day when we can be sure that we want certain devices to be on or off.  For example, I never make coffee after 2pm, so I could have a scheduled item that turns the coffee maker off at 2pm.  It's probably off anyway, though.  I could also use a timer as a trigger to set the "default" scene at 2pm, but what if I am doing dishes then?   It's not usual, but it's possible.  After all, if the times of day I did everything were to perfectly decided, I wouldn't need to do all of this nonsense anyway since I wouldn't ever need to use more than one device at the same time.  

Still, there are a few times of the day when we can guarantee everyone will be asleep and it is safe to revert to the default scene.  5am, for example.  This way, we make sure the AC is on before the sun comes up and it starts to get hot.  

Finally, in this specific case, it makes sense to use the temperature as a trigger.  Say, for example, if I forgot to change the scene back to "normal" after making coffee.  If the basement is cool enough, then it doesn't really matter if the AC is on.  If the basement is 28 ℃, though, then the AC needs to come on no matter what.  Even if it means rudely cutting power to the coffee machine - and even if it means cutting power to the dish washing machine while it is in opertation.  

This method is possible in my case because I have a priority, and the priority is the temperature of the basement - but what about more generally applicable methods?

Though the Switchbot app has limited options, the devices do support ITTT integration - which is one of the reasons I bought them.  Using ITTT, it is possible to do things such as log data, and set up various flows between different products that the normal apps might not support.  

One of these things is a trigger that lets you base an action on whether a certain plug is on or off, and how much power it is drawing.  This can be quite useful, because it is possible to set it such that is someone turns a single plug on manually, that can trigger a scene change to turn the other plugs off.  Whether this would happen fast enough to avoid the tripped breaker is another question - but it would be in most cases, since you wouldn't start drawing power the very second the switch was turned on.  

For example, I could press the power switch for the dish washer, which would cause the scene to change, and turn off the AC and coffee maker.  Meanwhile I am loading the dishes, etc.  By the time I actually want to start the cycle, it's safe to say the other devices will be turned off.  

Likewise, I could turn on the smart plug connected to the coffee maker, and then wait a few seconds before actually pressing the power button on the coffee maker itself to turn it on.

At any rate, in this kind of case, the power button on the smart plug is just acting as a kind of physical scene selector in this configuration.  

The power consumption trigger is even more interesting, because it means that when a certain device is drawing more than a certain amount of power, that can automatically disable the other devices.  When it goes back down it could re-enable the other devices - this could remove the need to manually change scenes.  

As an example, I could say something like "Whenever the dishwasher is drawing more than 100 watts, Switch to the Dishwasher scene" - but if I am using scenes to control things, then I would have already had to have been in the dishwasher scene.

Okay, so then maybe we can do away with scenes and say "Whenever the dishwasher is drawing more than 100 watts, turn off the AC" - sure, that would work - but then I would need dozens of different trigger combinations.