We don't need DC sockets as they dont solve any problems. The stupid simple AC mains distribution system is well tested and proven. Who cares that they provide up to 3kW. The "last meter" problem is perfectly solved using AC-DC wall warts and bricks. If the power supply dies, you buy a new one and just plug it in. No electrician required. Putting things in wall or central distribution is not a solution to any existing problem and introduces needless cost and complexity.
A better solution would be to get everyone on board with a single DC voltage and connector. Then we can buy larger multi socket bricks that are just AC-DC power strips. You can then add batteries and give it UPS functionality. But good luck getting everyone to agree on a single standard.
> A better solution would be to get everyone on board with a single DC voltage and connector
Why? For many things 6V is enough as it will downscale without too much loss to 5V/3V3 which is what most electronics run on... but everything that draws a boatload of power (computers, laptops, LED strips, ...) will go on 12V up to 24V, so if you want a standard it's either 12 or 24V which will introduce a lot of regulation waste in the form of heat in the device.
Wouldn't it be more efficient to have e.g. one DC power supply for the house that can power everything that needs DC power, instead of lots of individual (and likely cheap/inefficient) power supplies?
It seems like USB A/C are going to be that. You can already buy outlets that have both mains and USB ports, there are even dual USB C outlets now, that can do 30 watts:
I stayed in a newly built hotel a few years ago that had two USB-A sockets integrated in every single power outlet, both in the room and around the lobby.
What actually worries me about this is that they are all backed by tiny switch mode power supplies, and if not designed and built correctly they have a habit of exploding. So now your hotel has hundreds of potentially explody boxes hidden in the walls.
Do to circumstances beyond our control, we had to replace all the outlets in my parent's condo, so we used the USB (A) outlets. It works quite well. I do wonder if we will see USB-C quick charging outlets.
Is "Digital Electricity" a real thing? Its billed as an alternative to AC or DC. This may be as good a place as any to ask this question, but I am a hotel developer, and we've had a few people reaching out to us trying to sell "digital electricity" that sends high voltage over cat5 (up to 2000w per the Belden materials) by essentially sending high voltage for very brief blips with the ability to switch off before any damage occurs if a short is detected. they claim it is supposed to be significantly more efficient, doesn't require electricians to run cables, and its safer. I declined... but im still curious. basically every device in the room is connected via lan to a power server.
Looks like buzzword marketing bullshit to me. Apparently they're just sending pulsed DC power over Ethernet cables? Nothing else in that article is as new or exciting as they dressed it up to be. GFCI outlets are standard in modern houses, they claim to be safely transmitting "high voltage" but 120V is not, and the "digital" buzzword stinks of marketing.
>It transfers high levels of power over non-power cable
You can't beat physics. Wires heat up from current, regardless of whether it's AC, DC, or "digital" pulsed DC. I doubt Ethernet cable is rated for any significant amount of power, but searching for "cat6 max power" doesn't return any relevant results because search is broken in 2019.
It's also likely to be rather inneffecient, as they are converting from AC to DC and then potentially back to AC? There may be an advantage to pulsing DC but I'm not sure, typically AC is more efficient for power transmission because of lower losses for the same power over distance and higher transformer efficiency (no need for an inverter).
That sounds like the sort of thing your local electrical code authority might get very upset about. It's not clear what the actual voltage is? But if it's over "SELV" ratings different rules are going to apply.
From the material it sounds interesting but I'd be leery of the 600 Hz switching generating a ton of electrical noise and relying on the upstream systems to keep everyone safe. The idea sounds good but I can see a lot of ways this can go wrong outside of very controlled environments.
Oh wow, I would not want 2000w going through Ethernet. Both for the obvious electrical issues, and for the dangerous mixing of safe sockets and hot sockets.
No idea how this would be more efficient. Bursting voltage will lead to higher loses versus a continuous voltage. Are they claiming efficiency thanks to a centralized AC->DC converter?
I would check you local codes. Running Cat5 might not require an electrician, but that doesn't mean it doesn't mean it doesn't require a licensed installer. Especially if you want to run network over that Cat5, you'll want someone who knows what they're doing.
That said...Belden is reputable, but this doesn't sound like it's fully baked.
My first impression is that it smells like BS but let's take a closer look.
CAT6 cabling uses 4 pairs of AWG 24 wire. This type of wire typically comes with two options for insulation 250V and 600V, Let's be optimistic and use the latter. The maximum recommended current for AWG 24 wiring is 0.577A [1], as a reference PoE specs use 0.3A (if I remember correctly). Using these assumptions our maximum power transmission would be 4 (pairs of wire) * 600V * 0.577A = 1384.8W, this doesn't include power losses inside the wire itself. Belden's descriptions seem to indicate that power transmission is multiplexed in the time domain, which would reduce the power transmission capability even further.
Current limits on wiring are semi-arbitrary, what it really comes down to is how much heat generation is tolerable in the wires and the environment in which they reside. If we were to ignore the suggested current limit of 0.577A per core then it is possible to transmit 2000W. More specifically you would need 0.833A at 600V in 4 pairs of wire to get 2000W.
TLDR: The claims seem dubious. It is possible if the current limits for AWG 24 wire are are exceeded by about 2x.
Yes this and it is also much harder to switch off a heavy DC load than an AC one. Once current starts flowing in DC and you try to open a switch, an arc will form that never gets extinguished since the voltage doesn't cross 0 like it does in AC. Hence why switches are always significantly derated for DC versus AC.
That absolutely is. You could be better with 48 or even 24 volts, but then you are out of luck if you want to power a majority of devices which are 12v. So your only option is to go for USB-A wall socket which essentially is a wall-wart hidden in your wall. I do not see a good solution here.
Well, there is less drop with more copper, so it's more about costs. Cost of cables, DC-DC converters, power supplies and their efficiency determine optimal configuration. Probably going as high as cheap mass market DC-DC converters and PSUs allow is good rule of thumb for low voltage, so like 20-24 V. Beyond that better to go with high voltage.
Boats and RVs do this but the cables are gigantic compared to AC cables. Also as they age voltage drop becomes a big issue, especially on boats since the environment is so corrosive.
You have to choose wire gauges carefully. A lot of cables that connect power supplies to their devices have thin wires that don't loae much voltage over the meter or so of cable. But if you woukd extend that with an equal gauge wire to some meters if length, the conmected device will likely burn out around then as well.
I dont think DC wall socket is the problem - its the small electronics that each have their own power pack.
Ideally to me every led lamp, settop box, alarm clock, phone, laptop would not come with a power supply box. It would just take a USB cable or similar standard. Then you could buy a good quality power supply adapter that you can reuse for lots of products - and avoid the abundance of random adapters everywhere.
Interesting idea, but running an extra set of cables is a non-starter. The cost/benefit analysis would never make sense for existing structures, and newly built structures wouldn't do it unless it was almost certain to become a universal standard. This is a classic chicken-and-egg problem.
You would also still need something similar to a wall-wart to step down the voltage to whatever your device actually uses (e.g. from 12 V to 5 V to charge your phone), so its not clear how much benefit there would really be from such a system.
Whatever specs we adopted would probably also end up not being appropriate for some future devices, so we'd probably go back to a substantial number of devices bundling their own PSUs anyway.
Interesting idea, unlikely to ever be worth the cost. If wall-warts really bother you, then just invest in some wall outlets with integrated USB sockets - there are many good options on the market.
Also, the biggest non-starter is just how inefficient it is to move 12v any reasonable length. 12v domestic wiring only makes sense in very tiny small dwellings. (Think studio apartment or 3rd world country shack.)
Otherwise the voltage sag and resistance makes it cheaper and more efficient to do normal 120/240 voltage with device-specific converters. (For example, if I had to run 0-gauge cable from my breaker box throughout my house to support 12v, the cost of copper alone would be prohibitive.)
I honestly think standardizing on USB for devices that can use it is the best approach, given that we already have tiny AC->USB converters that don't block other plugs, and outlets with USB built-in are on the market. Furthermore, I wonder just how much we can shrink the typical wall-wart so it won't cover other plugs?
(I also think we're better off trying to do a global domestic 200 or 400 volt DC standard.)
The solar/RV/golfcart world has and entire ecosystem of standardized 12v DC power distribution and the appliances that use it if you really feel the need to have DC. Works pretty good...last year wired up a friends mountain cabin with 12v solar, batteries, inverter for AC, led lights, fans, dorm room sized DC fridge. Different manufacturers and everything popped together fine.
Most laptops can be charged from 12V auto-style sockets as well.
12V DC is fantastic for a solar setup (vacation cabin, off-grid home, or whatever). You can still have some standard AC outlets using an inverter, but there's no reason to have lights running off of AC -- especially if you have LEDs! Since inverters cause a slow but constant power drain, it makes sense to leave them off most of the time.
Edit: I also wanted to mention the amazing "3-way" fridges, which I was not aware of until looking into solar a few years ago. They can run on AC, DC, and propane, giving you an alternative if the power goes out. The RV world has tons of this stuff, and the appliances usually aren't that much more expensive. Some are even cheaper than regular appliances since they are usually more compact.
What DC connector does that use? My impression is that solar panels use MC4 connectors which have separate female and male and need two connectors for DC. But there is a convention for polarity.
Amateur radio has standardized on the Powerpole connector for 12V DC. Powerpole is hermaphroditic so don't have to worry about which end is plug or socket, and uses color coding for polarity.
I think that with low power LED lighting, as well as all rechargeable devices, there is a case for some (not all) 12VDC sockets around the house (and cars/vans/RVs). Actually, I think mobile applications will be first: in an RV, it makes no sense to have a big inverter to take your 12V batteries to 120V AC, just to plug in wall warts to charge to camera, phone, etc.
I have a friend who installed 12V in parts of his house, backed by a solar charged battery system. See my previous comment for some details:
Talking to this friend, we discussed the same problem as the OP. In RVs that are wired for battery power, they use wall-mounted cigarette lighter plugs, and you can buy some small appliances that use them. They are ugly and take up too much space, it would be so much better to have a plug of a regular shape and size. Of course it has to be polarized for DC, so something like ( - | ).
There is also the problem of breaking the arc in DC, so one prong needs to be longer and making contact further in so it can't arc outside the plug. Or maybe it needs some internal mechanism such as plastic slot covers that close and break the ark (like child-protected sockets have now). Anyway it definitely needs some research and design, but I think it would be cool to have a new 12VDC standard plug, then people could start designing products that use it to get the whole ecosystem started.
The article explains: USB A's power is too limited for a large percentage of household uses, and USB C is complicated and expensive, requiring digital circuitry to negotiate.
The current USB standards are great for small devices but for anything that requires more power it would be good to have something beefier, something less than the roughly 1500W a standard AC outlet provides but more than the current 15W or 20W of the typical USB port. 5V is just too low and requires a lot of compromise on the device side. I'd probably start with 12V or 24V to keep the current lower. I think there are newer USB ideas to provide something of that sort: https://www.digikey.com/en/articles/techzone/2017/mar/design...
> ...and incorporate a fuse to protect the appliance cable from fire. Those British BS1363, fused-mains-plug habits die hard.
Lots of car barrel connectors have fuses inside. I'm not seeing much reasoning behind not using the car barrel connectors, aside from 'it was designed for cars, not as a general purpose connector'.
They break easily. Spring loaded bits (actual springs). No properly defined standard and they vary a lot. Come out easily depending on quality. Easy to contact center pole to side poles on insertion. No ability to add earth.
What is the maximum power provided by PoE? Wikipedia is surprisingly vague on the subject, probably because there are multiple standards. PoE was never intended to power more than just network equipment.
I have to deal with this problem constantly and I haven't figured out a good solution yet. I'm not sure this is particularly meaningful in a normal mains-connected environment but as someone who's base power source is a finite amount of 24v DC, I hate eating the inversion losses when I could save ~7-16% using switching supplies off the main bus.
Currently everything I have is connected up with a hodgepodge of those green pluggable terminal blocks. It's not an elegant solution but it's hard to standardize on something, especially when I have devices that run off 5, 9, 12, 24 and 48 volts. I still run an inverter most of the time (I have two, pure and modified depending on the load).
I think it's possible to devise a decent solution here, I like the XLR based designs but I'm afraid of plugging things into the wrong voltage. I think maybe the good solution is to make a color-mapping for the common voltages up to 48v (past that you require an electrician to do wiring in the US iirc) and then make cables that are XLR on one end, and whatever-plug on the other end with an LED that lights up corresponding to the voltage. That way you know if your barrel jack is 12 or 5. It doesn't have to be foolproof, or even customer friendly really. People setting up DC buses to run all their electronics should be able to accept the responsibility of frying something if they give it too much juice.
Well...the daisy chains were the standard for mechanical connections. :-)
What there never was was a connection standard safe enough to put in a house, made to be (ab)used by normal people. 48v DC as it lives in the telco world is flat out dangerous if you aren't careful.
If none of the current plugs are usable, can we have a low-power plug standard based on PoE?
Having both ethernet and low power from one socket would be perfect for IoT devices, save people from having to run Ethernet wiring themselves afterwards, and cut down on wireless spectrum use.
And your 'smart fridge' would just plug into both outlets and use a relay to cut 230V if the motor doesn't need to run.
Wouldn't the labor/effort cost to run and terminate Ethernet vs. 120v wiring be significantly higher?
My perspective is just that of someone who's run a bit of both at an amateur level through my house, and finds terminating stupid-simple 120v wiring much, much easier than ethernet.
Yeah, we are kind of running low on actual high power devices to plug into residential outlets these days. Those that remain are pretty much confined to specific parts of specific rooms. Various stand alone cooking things on the kitchen counter. Hair dryer in the bathroom by the mirror. The vacuum cleaner seems to be the exception and there is a tendency toward built ins.
Heck, I don't know that there is even much need for high power ceiling lighting any more. Everything that people want to see with any detail is self illuminated these days. Just scatter some low power LEDs around (you don't even have to provide a way to turn them off) and you are done. If you actually want to read a paper book or do some knitting then an appropriate lamp is not going to take hardly any power as it would only have to illuminate a small area.
More than a low voltage plug (which I’d love) is the need for in wall smart plugs that have a wired connection rather than wifi. I can’t believe I’m the only person that wants this and while I’ve found a few in wall smart plugs, I’ve never found a wired one.
There are classic home automation systems like x10 that potentially predate wifi and offer wired solutions that use the power lines themselves for wired communication, you might want to check these out
A DC solution is WAY overdue. Put your hand on your AC->DC converter, or your wall-wart. Above ambient room temperature? Wasted energy. "It's only 2-10 watts." Multiply by 5 units (underestimated) per 100 million households. That's >= a gigawatt. 8700+ GwH / year.
That's aside from the environmental costs of making & disposing of these pernicioius devices. Time for that decades-old solution to retire.
I don't see how going to 12 V would help simplifying devices. Most chips don't run on 12 V, so one will anyway need a switch-mode power supply or linear regulators with big heat sinks inside each device. The added expense of a rectifier and mains-capable transformer is minimal.
On the other hand, at least fewer people would be electrocuted by their crappy Amazon USB chargers.
MisterTea|6 years ago
A better solution would be to get everyone on board with a single DC voltage and connector. Then we can buy larger multi socket bricks that are just AC-DC power strips. You can then add batteries and give it UPS functionality. But good luck getting everyone to agree on a single standard.
asteli|6 years ago
mschuster91|6 years ago
Why? For many things 6V is enough as it will downscale without too much loss to 5V/3V3 which is what most electronics run on... but everything that draws a boatload of power (computers, laptops, LED strips, ...) will go on 12V up to 24V, so if you want a standard it's either 12 or 24V which will introduce a lot of regulation waste in the form of heat in the device.
Wowfunhappy|6 years ago
rhinoceraptor|6 years ago
https://www.amazon.com/dp/B07PTWG5DV
rwmj|6 years ago
What actually worries me about this is that they are all backed by tiny switch mode power supplies, and if not designed and built correctly they have a habit of exploding. So now your hotel has hundreds of potentially explody boxes hidden in the walls.
Spooky23|6 years ago
protomyth|6 years ago
MaupitiBlue|6 years ago
ethagknight|6 years ago
https://www.belden.com/blog/smart-building/digital-electrici...
allovernow|6 years ago
>It transfers high levels of power over non-power cable
You can't beat physics. Wires heat up from current, regardless of whether it's AC, DC, or "digital" pulsed DC. I doubt Ethernet cable is rated for any significant amount of power, but searching for "cat6 max power" doesn't return any relevant results because search is broken in 2019.
It's also likely to be rather inneffecient, as they are converting from AC to DC and then potentially back to AC? There may be an advantage to pulsing DC but I'm not sure, typically AC is more efficient for power transmission because of lower losses for the same power over distance and higher transformer efficiency (no need for an inverter).
pjc50|6 years ago
zwieback|6 years ago
Danieru|6 years ago
No idea how this would be more efficient. Bursting voltage will lead to higher loses versus a continuous voltage. Are they claiming efficiency thanks to a centralized AC->DC converter?
unknown|6 years ago
[deleted]
kjs3|6 years ago
That said...Belden is reputable, but this doesn't sound like it's fully baked.
NwtnsMthd|6 years ago
CAT6 cabling uses 4 pairs of AWG 24 wire. This type of wire typically comes with two options for insulation 250V and 600V, Let's be optimistic and use the latter. The maximum recommended current for AWG 24 wiring is 0.577A [1], as a reference PoE specs use 0.3A (if I remember correctly). Using these assumptions our maximum power transmission would be 4 (pairs of wire) * 600V * 0.577A = 1384.8W, this doesn't include power losses inside the wire itself. Belden's descriptions seem to indicate that power transmission is multiplexed in the time domain, which would reduce the power transmission capability even further.
Current limits on wiring are semi-arbitrary, what it really comes down to is how much heat generation is tolerable in the wires and the environment in which they reside. If we were to ignore the suggested current limit of 0.577A per core then it is possible to transmit 2000W. More specifically you would need 0.833A at 600V in 4 pairs of wire to get 2000W.
TLDR: The claims seem dubious. It is possible if the current limits for AWG 24 wire are are exceeded by about 2x.
[1] https://www.powerstream.com/Wire_Size.htm
forgotmypwd123|6 years ago
planteen|6 years ago
aivisol|6 years ago
zzzcpan|6 years ago
wffurr|6 years ago
gmueckl|6 years ago
mark-r|6 years ago
rb808|6 years ago
Ideally to me every led lamp, settop box, alarm clock, phone, laptop would not come with a power supply box. It would just take a USB cable or similar standard. Then you could buy a good quality power supply adapter that you can reuse for lots of products - and avoid the abundance of random adapters everywhere.
atonse|6 years ago
I suspect that with PD, that allows even lamps to negotiate that they need more power, maybe?
alexhutcheson|6 years ago
You would also still need something similar to a wall-wart to step down the voltage to whatever your device actually uses (e.g. from 12 V to 5 V to charge your phone), so its not clear how much benefit there would really be from such a system.
Whatever specs we adopted would probably also end up not being appropriate for some future devices, so we'd probably go back to a substantial number of devices bundling their own PSUs anyway.
Interesting idea, unlikely to ever be worth the cost. If wall-warts really bother you, then just invest in some wall outlets with integrated USB sockets - there are many good options on the market.
gwbas1c|6 years ago
Otherwise the voltage sag and resistance makes it cheaper and more efficient to do normal 120/240 voltage with device-specific converters. (For example, if I had to run 0-gauge cable from my breaker box throughout my house to support 12v, the cost of copper alone would be prohibitive.)
I honestly think standardizing on USB for devices that can use it is the best approach, given that we already have tiny AC->USB converters that don't block other plugs, and outlets with USB built-in are on the market. Furthermore, I wonder just how much we can shrink the typical wall-wart so it won't cover other plugs?
(I also think we're better off trying to do a global domestic 200 or 400 volt DC standard.)
kjs3|6 years ago
iamnothere|6 years ago
12V DC is fantastic for a solar setup (vacation cabin, off-grid home, or whatever). You can still have some standard AC outlets using an inverter, but there's no reason to have lights running off of AC -- especially if you have LEDs! Since inverters cause a slow but constant power drain, it makes sense to leave them off most of the time.
Edit: I also wanted to mention the amazing "3-way" fridges, which I was not aware of until looking into solar a few years ago. They can run on AC, DC, and propane, giving you an alternative if the power goes out. The RV world has tons of this stuff, and the appliances usually aren't that much more expensive. Some are even cheaper than regular appliances since they are usually more compact.
ianburrell|6 years ago
Amateur radio has standardized on the Powerpole connector for 12V DC. Powerpole is hermaphroditic so don't have to worry about which end is plug or socket, and uses color coding for polarity.
205guy|6 years ago
I have a friend who installed 12V in parts of his house, backed by a solar charged battery system. See my previous comment for some details:
https://news.ycombinator.com/item?id=21109247
Talking to this friend, we discussed the same problem as the OP. In RVs that are wired for battery power, they use wall-mounted cigarette lighter plugs, and you can buy some small appliances that use them. They are ugly and take up too much space, it would be so much better to have a plug of a regular shape and size. Of course it has to be polarized for DC, so something like ( - | ).
There is also the problem of breaking the arc in DC, so one prong needs to be longer and making contact further in so it can't arc outside the plug. Or maybe it needs some internal mechanism such as plastic slot covers that close and break the ark (like child-protected sockets have now). Anyway it definitely needs some research and design, but I think it would be cool to have a new 12VDC standard plug, then people could start designing products that use it to get the whole ecosystem started.
jon-wood|6 years ago
ocdtrekkie|6 years ago
zwieback|6 years ago
theandrewbailey|6 years ago
Lots of car barrel connectors have fuses inside. I'm not seeing much reasoning behind not using the car barrel connectors, aside from 'it was designed for cars, not as a general purpose connector'.
consp|6 years ago
mark-r|6 years ago
jhallenworld|6 years ago
People in the 240V world get to pull 3KW from their wall sockets, I'm jealous.
http://wordpress.mrreid.org/2012/04/16/why-kettles-boil-slow...
nickhalfasleep|6 years ago
mark-r|6 years ago
WorldMaker|6 years ago
errantspark|6 years ago
Currently everything I have is connected up with a hodgepodge of those green pluggable terminal blocks. It's not an elegant solution but it's hard to standardize on something, especially when I have devices that run off 5, 9, 12, 24 and 48 volts. I still run an inverter most of the time (I have two, pure and modified depending on the load).
I think it's possible to devise a decent solution here, I like the XLR based designs but I'm afraid of plugging things into the wrong voltage. I think maybe the good solution is to make a color-mapping for the common voltages up to 48v (past that you require an electrician to do wiring in the US iirc) and then make cables that are XLR on one end, and whatever-plug on the other end with an LED that lights up corresponding to the voltage. That way you know if your barrel jack is 12 or 5. It doesn't have to be foolproof, or even customer friendly really. People setting up DC buses to run all their electronics should be able to accept the responsibility of frying something if they give it too much juice.
baybal2|6 years ago
Thus you see daisy chains of mechanical adaptors in telecom closets.
kjs3|6 years ago
What there never was was a connection standard safe enough to put in a house, made to be (ab)used by normal people. 48v DC as it lives in the telco world is flat out dangerous if you aren't careful.
unilynx|6 years ago
Having both ethernet and low power from one socket would be perfect for IoT devices, save people from having to run Ethernet wiring themselves afterwards, and cut down on wireless spectrum use.
And your 'smart fridge' would just plug into both outlets and use a relay to cut 230V if the motor doesn't need to run.
atourgates|6 years ago
My perspective is just that of someone who's run a bit of both at an amateur level through my house, and finds terminating stupid-simple 120v wiring much, much easier than ethernet.
mschuster91|6 years ago
rusk|6 years ago
upofadown|6 years ago
Heck, I don't know that there is even much need for high power ceiling lighting any more. Everything that people want to see with any detail is self illuminated these days. Just scatter some low power LEDs around (you don't even have to provide a way to turn them off) and you are done. If you actually want to read a paper book or do some knitting then an appropriate lamp is not going to take hardly any power as it would only have to illuminate a small area.
lostlogin|6 years ago
paulfurtado|6 years ago
gok|6 years ago
Passive USB-C cables should be fine up to 60 watts. Beyond that you need a chip to certify safe construction but that's a good thing.
8bitsrule|6 years ago
That's aside from the environmental costs of making & disposing of these pernicioius devices. Time for that decades-old solution to retire.
fsh|6 years ago
On the other hand, at least fewer people would be electrocuted by their crappy Amazon USB chargers.
fortran77|6 years ago
alexhutcheson|6 years ago
moonbug|6 years ago
jhoechtl|6 years ago