Dwelling 24 Volts

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Besoeker said:
Even if code compliant it may not be a very practical proposition.
Could you run an electric cooker, washing machine, clothes dryer, etc on a 24V supply?
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there are plenty of appliances made to run on 12 and 24 VDC for people who are off grid. not electric cookers or dryers though. Most people who are off grid would use propane for cooking and a clothes line for clothes drying.
 
Besoeker said:
Even if code compliant it may not be a very practical proposition.
Could you run an electric cooker, washing machine, clothes dryer, etc on a 24V supply?
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This is really not a real situation for me. It was a question that was brought up at our meeting on Tuesday and I felt that this technically wouldn't be compliant but the code member that answered it had the opinion that it was compliant.

Certainly, there are plenty of issues. Nowhere does the code say we must have a washing machine but rather it states we must have a 125 v circuit for the laundry.

I assume this may have come up in the mountains as a hunting cabiin. I am not sure how they can guarantee that there would be 24v all the time. Sure the power company loses power but if this is a solar array then you wouldn't be able to supply the 100 amps minimum req. for a dwelling
 
Dennis Alwon said:
This is really not a real situation for me. It was a question that was brought up at our meeting on Tuesday and I felt that this technically wouldn't be compliant but the code member that answered it had the opinion that it was compliant.

Certainly, there are plenty of issues. Nowhere does the code say we must have a washing machine but rather it states we must have a 125 v circuit for the laundry.

I assume this may have come up in the mountains as a hunting cabiin. I am not sure how they can guarantee that there would be 24v all the time. Sure the power company loses power but if this is a solar array then you wouldn't be able to supply the 100 amps minimum req. for a dwelling
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the code does not actually require a laundry receptacle. only a laundry receptacle in areas designated as a laundry.

210.52(F)
(F) Laundry Areas. In dwelling units, at least one receptacle
outlet shall be installed in areas designated for the installation
of laundry equipment.
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I don't think a PV array qualifies as a service. The minimum 100 A requirement only applies to services, IIRC.
 
petersonra said:
the code does not actually require a laundry receptacle. only a laundry receptacle in areas designated as a laundry.



I don't think a PV array qualifies as a service. The minimum 100 A requirement only applies to services, IIRC.
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Yes, but a dwelling is required to have a 100 amp service.. so that section is gone-- basically everything is being voided by 710-- doesn't make sense
 
Well yes, i'm just finishing up an off grid log cabin. I've tried to follow code as much as possible, but 100amps just isn't happening....

But i digress, if the point here is adopting partial code(s) at the expense and/or exclusion of others , it becomes rather problematic

~RJ~
 
Dennis Alwon said:
Yes, but a dwelling is required to have a 100 amp service.. so that section is gone-- basically everything is being voided by 710-- doesn't make sense
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Without looking it up, I don't think the code says you have to have a 100A minimum service. I think it says "minimum 100A disconnect".
 
I decided to see what living in Las Vegas was like for three months. I lived very comfortably in a van-sized RV with just 12 volts for lights, fans, pumps, phone charging, and laptop charging, and gas for heating and cooking. I parked on the street and in casino parking lots. I used utility power to charge my batteries every five days while overnighting at an RV park, but I could have used solar panels. So the answer is yes, you can live with just low voltage DC power.
 
Little Bill said:
Without looking it up, I don't think the code says you have to have a 100A minimum service. I think it says "minimum 100A disconnect".
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230.79 states what you say but 230.49 (B)states
(B) Specific Installations. In addition to the requirements of
230.42(A), the minimum ampacity for ungrounded conductors
for specific installations shall not be less than the rating of the
service disconnecting means specified in 230.79(A) through
(D).
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This , imo, makes the service size for a dwelling 100 amp
 
Chapter 7 installs are still subject to chapters 1 through 4, see 90.3.

It seems to me that due to the rather specialized equipment that uses 24 volts, and that you would have more current then with 120 or 240, you would need larger conductors, and that building a 24 volt system would cost more than a 120 volt system.

I am also completely failing to understand why somebody would not get an inverter, even a cheap HF one, and step the voltage up to 120.

Some cabins don't qualify as dwellings, they are no more than glorified sheds.

If this was an actual installation instead of academia, I think it'd be easier to ask the ahj if you can do it rather than thumb through the entire NEC finding one or two sections that seem to prohibit it. But hey, we can't ever do anything the easy way around here, right? LOL
 
It may be a real situation IDK, however it is a curiousity. I stated earlier that a cmp member says it is compliant but I am not so sure because we can't just ignore everything in chapter 2....

Say it meets the definition of a dwelling-- some are now 200-300 sq.ft I am wiring one with my class from a community college that is about 600 sq.ft.
 
Yeah there's an archy in town pedaling 'micro' homes , all i can think of wiring them is the 'old lady in a shoe' fairy tale.....~RJ~
 
Dennis Alwon said:
230.79 states what you say but 230.49 (B)states


This , imo, makes the service size for a dwelling 100 amp
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I'm not too good with art 690, and it's all changed in the '17

I would think part III would address this? but i can't finger anything specific....:(

IMHO , if the 'dwelling' has a washer machine , it'd have to meet NEC , as in if it had a 'service'

Now I'm not sure if a stand alone PV & genny comprise 'service' or not here?

~RJ~
 
Coppersmith said:
I decided to see what living in Las Vegas was like for three months. I lived very comfortably in a van-sized RV with just 12 volts for lights, fans, pumps, phone charging, and laptop charging, and gas for heating and cooking. I parked on the street and in casino parking lots. I used utility power to charge my batteries every five days while overnighting at an RV park, but I could have used solar panels. So the answer is yes, you can live with just low voltage DC power.
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You could live without electricity at all. My grandparents in the Outer Hebrides did.
 
Little Bill said:
Without looking it up, I don't think the code says you have to have a 100A minimum service. I think it says "minimum 100A disconnect".
Click to expand...

Dennis Alwon said:
230.79 states what you say but 230.49 (B)states


This , imo, makes the service size for a dwelling 100 amp
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If off grid there is no service. However 225.39(C) has same 100 amp requirement for the disconnecting means for an outdoor feeder supplied dwelling.

Neither says whether the source needs to have 100 amp capability though. Even if you were to run off a generator, at 120 or 120/240 volts, many homes with limited load in their design wouldn't utilize a generator that can deliver 100 amps.

This all comes down to what the rules are in the location of the home. Within a city limits the rules are more likely to be stricter. Out in a remote location, there may be little rules at all, or at least some lack of enforcement of them, especially if no utility service is supplied to it.

Here if you wanted a cabin by the river, the county will want a building permit. This is for zoning purposes as well as property taxes purposes, nobody inspects the building to see if it meets any building codes. If you run utility power to it, it doesn't get energized if there is no electrical permit. If there is existing service somewhere that you will power it from though it is technically not right, it is sort of easy to get away with it.
 
kwired said:
If off grid there is no service. However 225.39(C) has same 100 amp requirement for the disconnecting means for an outdoor feeder supplied dwelling.

Neither says whether the source needs to have 100 amp capability though.
....snip....
nobody inspects the building to see if it meets any building codes. If you run utility power to it, it doesn't get energized if there is no electrical permit. If there is existing service somewhere that you will power it from though it is technically not right, it is sort of easy to get away with it.
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I agree with these good points. However if they want insurance on the structure the AHJ may not just be the local building official but also the insurance co. I would focus on 90.1(A) and (B) the job of the NEC is not to select a voltage or system other than for practical safeguarding of persons and property.
The issue of 'Additional dwelling units' (ADU), 'Tiny Homes', Cabins, Yurts whatever they call it. I'd say 'small dwelling unit' it is upon us (the NEC).
I would be careful to go by the NEC definition of a dwelling unit "Dwelling Unit. A single unit, providing complete and inde-
pendent living facilities for one or more persons, including permanent provisions for living, sleeping, cooking, and sanitation."
If its a hunting cabin with a detached outhouse for sanitation you dont have a dwelling unit.

I'd say article 230 is your minimum design requirement IF your using standard systems. And if you dont have voltage's recognized by NEC 220.5 and they are equal to or lower than the limits in 210.6 (it does not specify AC so DC is included)
And if our 24V (AC or DC) dwelling is a dwelling unit per NEC
I would look at article 411, and the historical article 720 that used to cover such rural 32V Delco systems in the days before grid service.
http://www.doctordelco.com/Dr._Delco/Delco-Light/Delco-Light.html
We could also pretend there were wheels on it and inspect it as a 'Recreational Vehicle' ART 551. And if there was no desire to supply 120V or 240V appliances in the future lots of that would not apply. But that's where I would go.
just my two cents
Cheers
 
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