Show notes
The lowly circuit breaker was first patented by Thomas Edison and hasn’t been updated much since — until Atom Power CEO Ryan Kennedy came along and made a digital version. In this episode, he describes the basics of the digital circuit breaker, the ways it’s making a difference in the EV charging market, and its gamechanging potential. (PDF transcript)(Active transcript)Text transcript:David RobertsThere is perhaps no building block of the electricity grid more fundamental, ubiquitous, and overlooked than the humble circuit breaker. Every electronic device that is attached to the grid runs through a circuit breaker, a device that automatically shuts off current in the case of a fault or surge.Currently, though they have become extremely reliable, circuit breakers still rely on technology that was patented by Thomas Edison. They operate purely through electromechanical forces, with no digital control.My guest today, Ryan Kennedy, is the first person to develop, patent, pass UL testing with, and commercialize a digital circuit breaker. It is solid state — that is, it has no moving parts — and current is controlled entirely through semiconductors.In addition to being faster and safer than electromechanical equivalents, each digital circuit breaker contains within it its own firmware and software, which can be programmed to emulate, and thereby replace, any number of other software-driven devices like demand management systems, load controllers, meters, and surge protectors.Kennedy's company, Atom Power, is currently focused on the electric-vehicle charging market, offering smart load balancing and management from a centralized circuit board, replacing the need for complicated hardware and software in the EV chargers themselves.But the ultimate applications for a digital circuit breaker are endless. Everywhere they are attached, a grid becomes a smart grid and appliances become smart appliances. If even a substantial fraction of today's circuit breakers could be replaced with digital equivalents, it would bring unprecedented visibility and control to millions of distributed energy devices, enabling all sorts of sophisticated demand management.I was extremely geeked to talk to Kennedy about the basics of circuit breakers, their application to EV charging, and the many possibilities that lie beyond.Alright, then. Ryan Kennedy, welcome to Volts. Thank you so much for coming.Ryan KennedyDavid, thank you for having me.David RobertsThis is awesome. I'm so interested in this widget and its possibilities, but I think to help people get their heads around it. Before we get too deep into anything, let's just start at the most basic level. For those of us who were humanities majors and never took any electrical engineering or anything, let's just talk about what is a circuit breaker. I know people are very vaguely aware of circuit breakers. They are in a circuit box in your garage. Occasionally, your power goes out, and you wander out to your garage and flip switches around and try to see what works.But, I think that's probably the extent of most people's knowledge. So let's just start there.Ryan KennedyCircuit breakers, electrically speaking, are one of the oldest products on the market. They first were invented, at least patented by Thomas Edison to show you how far back they go. But, they're effectively a method of interrupting the flow of electricity when things go wrong. Too much current, short circuits, things like that. The purpose of the circuit breaker is to simply open the circuit when those things happen and protect from fire, primarily.David RobertsAnd, presumably, protecting the appliances and the things on the other end of the wire, too right.Ryan KennedyGenerally, that's the assumption, though I don't know that it's necessarily the explicit purpose. I think the more explicit purpose is to prevent fire. That could mean your equipment may go bad, in the process, but generally speaking, to prevent fire and hazardous conditions from electricity.David RobertsAnd so, every appliance, or device, or anything that uses electricity from the grid is connected to the grid through a circuit breaker. Is that true? Is that a universal rule?Ryan KennedyThat's right. Actually, the easiest way to visualize that is to think about the home or apartment, where you have a panel with breakers in it that typically open the front door and you can see breakers in there, and you flip switches and things go wrong. So basically, you have a big power feed from the utility that comes into that home to that panel, and then out of that panel, power gets distributed through each one of those little circuit breakers out to individual loads in your home, such as hot water, HVAC, lights, receptacles. That scales out. Commercial buildings and industrial buildings and data centers are the exact same thing.I mean, there's more breakers, and they often get bigger, but it's the exact same architecture across the entire planet. Or the circuit breaker always is the thing that sits in front of the thing that consumes energy.David RobertsRight. And so, the purpose of these things is to basically shut off current if something goes wrong. How do they do that currently?Ryan KennedyThere's a couple of different ways, but the most predominant way is it gets into a little bit of engineering speak. So I'll try not to dive too deep, but basically, it's through thermals and magnetics. So, there's kind of two situations you would have. Let's just pick on the home a little bit because the same problems scale upward to commercial, industrial buildings. When you say, plug in way too many things into the outlet, the breaker will trip. And that's tripped through thermals, means that too much current is flowing, things get hot, and some expansion happens inside of the circuit breaker. And, mechanically speaking, it flips a spring, and causes the breaker to open.David RobertsSo it's not a heat sensor. It's literally the heat expands something physical, and the physical change trips something.Ryan KennedyIt literally expands the metal inside of the breaker to open it up. That's what happens. The second, there's two methods—that was thermal—the second is called magnetic. That mechanism, it operates physically the same way. The actual springs and levers inside of the breaker open up the same way. But what causes it is different. So, magnetic happens when you have, say, a short circuit. Don't do this at home, but if you took one of your wires from your home and just put it into a pool. Lots of current flow all of a sudden, really really fast. That's called a short circuit.And you don't want to wait for things to heat up because that's when really bad things happen. So what happens is an enormous amount of current starts flowing through that circuit breaker, creates a pretty quick magnetic field that basically pushes the metals apart inside of the breaker to open it up, as well. So it's very much a passive device in the sense that there's nothing in them that say, oh, that's that, or this is that, so, therefore, I need to do this. It's a reaction of the metals inside of the product itself. It's quite an old technology, actually.If you open up the circuit breaker, it looks like a mousetrap condensed.David RobertsYeah, tiny little mousetrap that's basically set off by heat or a magnetic field. You think about electricity these days. You think about all our sort of digital devices and digital controls. And it's a little bit wild that on every single line going to every single device, there's this mousetrap, just so old fashioned. That always struck me. It's so weirdly old fashioned. A little piece of metal with, like, springs on it that springs shut to cut off your electricity. So it's very mechanical. Let's say electromechanical, as you say.Ryan KennedyYes, very established technology that is, in today's world, relatively ancient from a technological standpoint. But, to achieve those basic results of circuit protection, they work. The basic results of circuit protection.David RobertsRight. And it's passive, as we say, just responds to perturbations, and, I guess you would say, dumb, in that, it doesn't know there's no awareness of what's happening or why it's happening. It's just metal expands, it flips, it cuts off.Ryan KennedyThat's correct.David RobertsSo there must be millions and millions and millions of these things. I mean, if there's one of these things between every electrical load and the grid, there must be billions out there in the world.Ryan KennedyLikely, yes. I think your first number was correct. Millions and millions and millions.David RobertsSo what you've done is make a digital circuit breaker, which works differently than the electromechanical. So why don't we just start with if it's not a physical reaction, if it's not a physical thing happening inside this digital circuit breaker, what is happening? How does it work?Ryan KennedyWe can dive into the technical and how it works, and then it'd be good to talk about kind of why we're doing that. So first, the technical. And the reason I say that is because, well, breakers work. Why do anything to them? Right? But technically speaking, what we've done is we've created a digital circuit breaker. More specifically, we call that a solid state circuit breaker. What that is is saying, hey, instead of using mechanics or mechanical devices, meaning like metal on metal, the things we just talked about to conduct electricity through a breaker, let us use semiconductors instead.So semiconductors are a broad ranging topic, but basically means that you can control current with a small digital input much like you can on your phone or computer, et cetera. But scale that up to power and say well, let's make a circuit breaker with semiconductors so that you can now interrupt, in the case of protection, the circuits when bad things happen with semiconductors instead of mechanics. With that, we overlay. So, what happens when you go to a semiconductor approach? It is very much an analog, as if you said what's the difference in a rotary phone versus a smartphone?It's making that leap all at once. Because now with digital control being semiconductor control at the breaker, it means that you can now put smart things inside of the breaker and make it do things and add value that it typically didn't have. That's what we're doing.David RobertsI just want to stress on the core function of shutting off current in danger. Even on that core function, it's faster. It's better and faster than a mechanical device. Is that right?Ryan KennedyThat's correct. By multiple orders of magnitude. So to give you an idea, we are, roughly speaking, about 3,000 times faster than most mechanical breakers in the market. That equates to two things. One is safety. There's some old footage of us, that we don't do so much anymore, of slapping hot wires together to kind of show that safety function. Don't try that at home either. So that's one thing which is actually quite important when you scale into larger buildings because there's more energy and more utility and short circuits can be explosive events. So it definitely helps in that regard.David RobertsAnd you say conventional circuit breakers work, but we should note that there are faults, there are fires, there are arc—what do they call them? Arc.Ryan KennedyArc flash.David RobertsWhatever—yeah. They're not 100%.Ryan KennedyThat's right. What's interesting about—not so much in residential although this can't happen in residential—but when you scale up to, like, the larger buildings, commercially in the industrial space and especially in data centers where the utility services are very large, you can have catastrophic events from short circuits that are balls of fire. Now, the breakers will open, but that doesn't mean a ball of fire didn't happen in the process. Right. So that does happen. I mean, in the worst case in my in my past life, I used to design buildings and also worked for, you know, a contracting firm.So I've seen, particularly in one instance in a high rise building where there was a short circuit in the electrical room on, like, the 19th or 20th floor, and it blew the doors off of the electrical room. And these are like commercial grade steel doors that got blown off the electrical room. So it's an amazing force that can be had when you get into the bigger buildings. But, I digress a little bit. It certainly eliminates that problem. Let's put it that way. Go into a semiconductor just purely based on speed.David RobertsAnd that's just because a digital signal travels at the speed of light. Right. And it's just faster than any mechanical reaction.Ryan KennedyYeah, inherently a semiconductor is going to be, like I said, including propagation delays and things like that within the compute and sensing, we're around 3000 times. And to give you an idea, that's in the microsecond range as opposed to millisecond range or millisecond spurl in the case of mechanical circuit breakers. Now, okay, micro milli. But electricity does move virtually at the speed of light. So arc flash propagates not quite that quick but pretty quick. Whereas that time really really matters. So yeah, the impact to the safety is effectively arc flash just doesn't happen on the output of our product, even in the largest utility services.David RobertsSo you get the basic function of the circuit breaker is faster and better. But then, as you say, you have this device that has semiconductors in it and you can put other stuff in there too. So maybe just describe like, I know what a circuit breaker looks like. It sort of fits in the slot in my circuit box, so I have the vague idea kind of what it looks like. What does your thing look like? Is it the same size? Does it, what is it composed of? What does it look like?Ryan KennedyToday, what we have on the market doesn't look so much like what you would see in your home. It looks more the size of a commercial grade circuit breaker. So can't fit in the residential panel yet, with a strong emphasis on yet, but we do have a similar form factor of commercial grade circuit breakers.David RobertsAnd is that just the difficulty of shrinking down little computers and stuff? I mean, is it that simple?Ryan KennedyNot quite the compute, it's more the power semiconductors that actually do the switching. So we're on this incredible curve that probably could take up a large portion of this conversation but also simplify it to basically mean that the world of power semiconductors is advancing quite under the hood actually of everything else that's happening. Power semiconductors are what enable electric vehicles to be as efficient and as effective as they are. Power conversion and solar—UPS has lots of things power conversion related. They are advancing at a pretty rapid rate from a power density standpoint. Power density meaning like how much power you can actually pack into that power semiconductor.So power density is going up, size is getting smaller. That plays into our own internal strategy as a company to optimize the form factor in the coming couple of years to where it becomes much more of a universal product that can fit into existing panel boards. But today, we have—it looks like a small box that fits into our—we manufacture panel boards as well, so you don't have to figure that out, but we figured all that out for you. Make panel boards, circuit breakers, everything as a whole system.I always say that there's two major compo…
Full show notes at the publisher 
Our TOPPODCAST Picks 
Stay Connected
