How Long Until Low Volt DC dominates building power distribution?

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
It's not like this is a such a new idea. Lately I've been dealing with a somewhat more affluent clientele, and I've seen a few low-voltage lighting systems. One was 60ish years old. They all seems to be one-offs. Something that a richer person had the money to throw at to be cutting edge, and by 10 years later the technology had moved on. No sign of a trend that the approach is moving toward a long-term standard or reducing costs. I doubt that pattern will change. Even if the reason is simply that (like VHS vs. Betamax), 120VAC is just too established, regardless of whether it's better.
 

tom baker

First Chief Moderator
Staff member
Low voltage power is nothing new because actually low voltage was used decades ago to power many rural houses. If you look, you can find lighting and appliances like refrigerators and irons that were available at the time.

-Hal
To the OP, the NEC already has an article on DC power distribution. Article 720 dates from early 1930s, like Hal said it was very popular, do a google search for Delco light plants.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
To the OP, the NEC already has an article on DC power distribution. Article 720 dates from early 1930s, like Hal said it was very popular, do a google search for Delco light plants.
Then make a public comment to the NFPA to keep 720 in the code, they are removing it in 2023.
This is bad for any folks left that want a off grid 'legally built' cabin that meets the NEC definition of a dwelling.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Although conversion losses remain high, the resistive line losses go away once you have superconducting transmission lines. And at that point you would really like to be able to eliminate the inductive and capacitive loading associated with AC transmission.
Not likely to affect local distribution any time soon, of course.

BTW, I am fixing the spelling error in the thread title.
 

Besoeker3

Senior Member
Location
UK
Occupation
Electrical Engineer
Although conversion losses remain high, the resistive line losses go away once you have superconducting transmission lines. And at that point you would really like to be able to eliminate the inductive and capacitive loading associated with AC transmission.
Not likely to affect local distribution any time soon, of course.

BTW, I am fixing the spelling error in the thread title.
Actually, there have been HVDC lines for a decade or more. I recall them for ASEA as they were but this is quite unrelated to the domestic low voltage kit being suggested by the original poster.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Actually, there have been HVDC lines for a decade or more. I recall them for ASEA as they were but this is quite unrelated to the domestic low voltage kit being suggested by the original poster.
Yes, and one of their advantages for interties is that they remove the need for phase sync between endpoints.
 

Besoeker3

Senior Member
Location
UK
Occupation
Electrical Engineer
Lower voltage means larger cables and higher cost of installation. We should be thinking about going higher than 120 volts, not lower.
Yes. For much of Britain, Europe, and a lot of other countries use 230V AC single phase or 400V three phase.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Lower voltage means larger cables and higher cost of installation. We should be thinking about going higher than 120 volts, not lower.
Yes. For much of Britain, Europe, and a lot of other countries use 230V AC single phase or 400V three phase.

Well, it seems that the "IT types" don't have a grasp of electrical engineering. They only have a familiarity with what they and their industry works with and to them it seems like it would be a great idea instead of what we do now. If they knew what they were talking about they wouldn't be saying it.

-Hal
 

paulengr

Senior Member
Well, it seems that the "IT types" don't have a grasp of electrical engineering. They only have a familiarity with what they and their industry works with and to them it seems like it would be a great idea instead of what we do now. If they knew what they were talking about they wouldn't be saying it.

-Hal

So imagine if every so often randomly your main breaker turned blue and tripped out for no reason. Then you have to reset everything in the house after resetting it. And once a year it trips out and the only way to recover is to sit on the phone for two hours, talk to some guy in a foreign country reading from a script in broken English, and pay thousands for a new license. Or that about once a month in the morning when you go to the shower or use the coffee maker nothing works for a half hour while the house downloads an update then when you hit the light switch, instead the blender turns on, Or that the voltage in your house gradually lowered over time until it was no longer usable and every 5 years you are told to simply replace the entire house. Or that all electricians do for service is flip the breaker off and on a couple times and if that doesn’t work, they give up and leave.

Yeah, we need IT people doing electrical work. They don’t do enough damage as it is. Why we tolerate this level of incompetence and lack of reliability is beyond me. Anyone on this forum doing this kind of thing would be fired and never paid, Yet it’s ok if a nerdy kid with horn rimmed glasses and a certificate from the cancel culture guys does it.
 
BTW, just like electrical workers and engineers, there are both good and bad IT workers; "IT" is now a rather wide range of tasks and skills (very basic "is it plugged in?" support to operating email systems for millions of subscribers, etc) and some of the people actually understand things like "risk management" and "good design". Some could even wire a panel more neatly than many electricians I've seen :LOL:.
 

kwired

Electron manager
Location
NE Nebraska
BTW, just like electrical workers and engineers, there are both good and bad IT workers; "IT" is now a rather wide range of tasks and skills (very basic "is it plugged in?" support to operating email systems for millions of subscribers, etc) and some of the people actually understand things like "risk management" and "good design". Some could even wire a panel more neatly than many electricians I've seen :LOL:.
My son is basically an IT person, but does a lot more than just "is it plugged in". Network security of the facility he works for is probably one of the most important things he is a part of.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
"IT" is now a rather wide range of tasks and skills (very basic "is it plugged in?" support to operating email systems for millions of subscribers, etc) and some of the people actually understand things like "risk management" and "good design".
Willing to bet that those wouldn't be the people who want to take over the world with USB power. I assume they have better things to do.
Some could even wire a panel more neatly than many electricians I've seen
Maybe so, but do they understand what they are doing?

-Hal
 
Maybe so, but do they understand what they are doing?
Actually yes, but granted that they're very much in the minority (and they'd laugh at the USB-powered house idea). Certainly some "IT techs" can not even spell "reboot"....

A parallel is audio engineers- some subscribe to the "one power phase" myth and some know what ground loops are and how to avoid or mitigate them (and even know things like Kirchhoff's law).
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
So imagine if every so often randomly your main breaker turned blue and tripped out for no reason. Then you have to reset everything in the house after resetting it. And once a year it trips out and the only way to recover is to sit on the phone for two hours, talk to some guy in a foreign country reading from a script in broken English, and pay thousands for a new license. Or that about once a month in the morning when you go to the shower or use the coffee maker nothing works for a half hour while the house downloads an update then when you hit the light switch, instead the blender turns on, Or that the voltage in your house gradually lowered over time until it was no longer usable and every 5 years you are told to simply replace the entire house. Or that all electricians do for service is flip the breaker off and on a couple times and if that doesn’t work, they give up and leave.

Yeah, we need IT people doing electrical work. They don’t do enough damage as it is. Why we tolerate this level of incompetence and lack of reliability is beyond me. Anyone on this forum doing this kind of thing would be fired and never paid, Yet it’s ok if a nerdy kid with horn rimmed glasses and a certificate from the cancel culture guys does it.
Back in the day, the "field service engineers" for Digital Equipment Corporation (DEC) were required to replace modules rather than troubleshooting the problem to the component level. This led to a lot of jokes, many of which they told on themselves.
My favorite was "How many DEC FSEs does it take to change a flat tire?"
Answer (in spoiler text, so click the button to read it)
It takes five. Four to lift up the car and one to swap tires till he finds the one that's flat.
 
I remember that period, although the modules were becoming more complex and field-replacing MSI/LSI chips is not really a field operation.

The following questions were-
How long does it take? Depends on how many flat spares they brought.
What if there are more than one flat? "Let's change the carb, see if that helps."
 

JRK_Labs

Member
Location
Berwick, PA USA
Occupation
Information Technology
I'm currently designing a new Net Zero home for construction in PA later this year. There's a very good chance that all lighting and switches will be 24VDC tied to a Loxone home automation system. There are already commercial buildings using 48 VDC POE (Power Over Ethernet) as well. LEDs have made it possible for low voltage lighting to really take off. The project is planning to have at least a grid-tied solar array. If batteries are brought into the mix, it will be possible for the lighting and automation system to be powered purely from DC power.

Jeff
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I'm currently designing a new Net Zero home for construction in PA later this year. There's a very good chance that all lighting and switches will be 24VDC tied to a Loxone home automation system. There are already commercial buildings using 48 VDC POE (Power Over Ethernet) as well. LEDs have made it possible for low voltage lighting to really take off. The project is planning to have at least a grid-tied solar array. If batteries are brought into the mix, it will be possible for the lighting and automation system to be powered purely from DC power.

Jeff

In 25 words or less, tell us what advantage that has over conventional power, considering that 120 volts will still be needed for appliances, etc.

-Hal
 
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