If your house gets 800V DC you're still gonna need "bricks" to convert that to 5VDC of 12VDC (or maybe 19VDC) that most of the things that currently have "bricks" need.
And if your house gets lower voltage DC, you're gonna have the problem of worth-stealing sized wiring to run your stove, water heater, or car charger.
I reckon it'd be nice to have USB C PD ports everywhere I have a 220VAC power point, but 5 years ago that'd have been a USB type A port - and even now those'd be getting close to useless. We use a Type I (AS/NZS 2112) power point plug here - and that hasn't needed to change in probably a century. I doubt there's ever been a low voltage DC plug/socket standard that's lasted in use for anything like that long - probably the old "car cigarette lighter" 12DC thing? I'm glad I don't have a house full of those.
My understanding is that DC breakers are somewhat prone to fires for this reason, too.
The electricians I was working with also told me stories about how with the really big breakers, you don't stand in front of it when you throw it, because sometimes it can turn into a cloud of molten metal vapor. And that's just using them as intended.
Allegedly
While on "work experience" from high school I was put on washing power lines coming straight out of the local power station near the ocean - lots of salt buildups to clear.
Same deal, flashover suits and occasional arcs .. and much laughter from the ground operators who drifted the work bucket close.
Another story in the same line is that I heard that a horse got killed by contact with a lantern battery, but I don't have any reference for that, just a story by a family member that collected coaches.
It would have self-extinguished if you waited long enough for the probe to vaporize.
I think its that DC breakers are more expensive, so people use AC rated breakers instead. They are both rated for 400v @10 amps, its the same thing right?
It turns out they are not, and most people, even electronics types rarely play with 200v+ of DC.
(My stand mixer is the lone sad exception)
I spent a few years getting flown out around the world to service gear at different datacenters. I learned to pack an IEC 60320 C14 to NEMA 5-15R adapter cable and a dumb, un-protected* NEMA 5-15R power strip. While on-site at the datacenters, an empty PDU receptacle was often easy to find. At hotels, I'd bring home a native cable borrowed from or given to me by the native datacenter staff or I'd ask the hotel front desk to borrow a "computer power cable," (more often, I'd just show them a photo) and they generally were able to lend me one. It worked great. I never found a power supply that wasn't content with 208 or 240V.
Example adapters: https://www.amazon.com/dp/B0FD7PHB7Y or https://www.amazon.com/dp/B01IBIC1XG
*: Some fancier power strips with surge suppression have a MOV over-voltage varistor that may burn up if given 200V+, rendering the power strip useless. Hence, unprotected strips are necessary.
AC arcs are easier to extinguish than DC arcs, but DC will creep much easier than AC and so on.
From a personal point of view: I've worked enough with both up to about 1KV at appreciable power levels and much higher than that at reduced power. Up to 50V or so I'd rather work with DC than AC but they're not much different. Up to 400V or so above that I'd much rather have AC and above 400V the answer is 'neither' because you're in some kind of gray zone where creep is still low so you won't know something is amiss until it is too late. And above 1KV in normal settings (say, picture tubes in old small b&w tvs and higher up when they're color and larger) and it will throw you right across the room but you'll likely live because the currents are low.
HF HV... now that's a different matter and I'm very respectful of anything in that domain, and still have a burn from a Tronser trimmer more than 45 years after it happened. Note to self: keep eye on SWR meter/Spectrum analyzer and finger position while trimming large end stages.
Can you say more about "creep"? Is the resistance changing? Or is material actually migrating?
Also curious why it's worse using DC.
Electromagnets dont work for DC, so your breaker will never trip. For thermal protection, you need current, so that checks out, and it would make sense for it to be rated under 50V as thats considered the highest voltage thats not life threatening on touch.
PV Batteries in general have a very high current (100s of A) at ~50Vish volts, so I dont think there's a major usecase for using household breakers for them.
Im still not getting your point BTW, switches and breakers are two separate things, with different workings, and household (and datacenter) DC would be I think around 400ish V, which is a bit higher than the peak voltage of AC, but still within the arc limits of household wiring (at least in 230V countries).
The advantage of DC is that you use your wiring more efficiently as the mean and peak wattage is the same at all times. Going with 48V would mean high resistive losses.
If electromagnets don't work for DC then what am I supposed to do with this pile of DC solenoids and relays? ;)
> PV Batteries in general have a very high current (100s of A) at ~50Vish volts, so I dont think there's a major usecase for using household breakers for them.
That's what the SCCR rating is for. When there's a fault you're going to have a LOT of current flowing until your safety kicks in. Something like the grid or a battery bank will happily provide thousands of amps almost instantaneously. Breakers designed for protecting building wiring are rated for this. Now, most household breakers aren't dual DC/AC rated, but you can actually buy DC rated breakers that fit in a home panel (Square D QO series).
> Im still not getting your point BTW, switches and breakers are two separate things, with different workings, and household (and datacenter) DC would be I think around 400ish V, which is a bit higher than the peak voltage of AC, but still within the arc limits of household wiring (at least in 230V countries).
My point is that there isn't any material reason why DC can't be as safe as AC, all the proper safety equipment already exists. Extinguishing a DC arc during a fault is a solved problem for equipment at household scale.
> The advantage of DC is that you use your wiring more efficiently as the mean and peak wattage is the same at all times. Going with 48V would mean high resistive losses.
I just mentioned 48V because it's a common equipment voltage for household DC systems. 400V would be good for big motors and resistive heating loads.
Regarding DC vs AC and wiring efficiency, talking about mean vs peak wattage just confuses the issue. 1 volt DC is 1 volt RMS. It is an apples-to-apples comparison. If you want to say "we can use 170VDC or 120VAC with the same insulation withstand rating, and at lower current for the same power", then that is absolutely true. But your common 600V THHN building wire won't care if you're using 400V AC or DC, so it's mostly immaterial.
Thinking about the failure modes gave me the heebie jeebies, but the gas had been disconnected ages prior.
Once you get into higher power (laptops and up), switching and distribution get harder, so the advantages fade.
For bigger appliances (fridge, etc), AC is fine + practical.
However, there's also PoE (24 or 48V!), so maybe that's the right approach. It's not like each outlet is going to run a heater anyway.
Unless you mean running AC and installing inverters in the wall? What is this even for? All my electronics are DC but critically they all require different voltages. The only thing I might benefit from would be higher voltage service because there are times that 15 A at 120 V doesn't cut it.
The irony...