Show HN: My $1k self-install, off-grid solar backup build for renters
sunboxlabs.com
sunboxlabs.com
I like the idea of solar, and of backups, and of figuring out how to live comfortably in rentals, and of being mobile, but...
I'm pretty sure that my own real-life landlord would flip out, if he came to the door, and saw that charger box bolted to the wall, and the bare terminals of an Alibaba special "SCREMOWER" large lithium battery pack.
Before he even saw that cabling. Which I think (with those lengths, and tacked up like that) would be an electrical code violation here.
Would insurance even cover a fire?
Also, if there's later an expensive roof leak, there'd be questions about whether it had been caused by installation of the panels (even though no holes were drilled). And is there a liability risk if the panel gets blown off.
And would insurance cover any of that?
Were I in landlord's position myself, I'd have much of the same concerns.
Safety hazards I see include: Solar panels on the roof that aren’t bolted dow; I don’t care what wind speed they’re rated for. Wires running from them to the inside of the house not in conduit and not secured. A high energy battery pack not NRTL listed. Extension cords draped through the house permanently installed (within the expansive definition of permanently installed used by the NEC)
In addition running the wires in through a cracked window creates an unacceptable risk of water damage.
That said, it’s a cool project. Just do this in a barn you own not a house I own.
Even once solar makes sense for the house I live in, its a tougher sell in a rental: If I were to do install solar on a rental, there's the added complexity of "how do I charge the tenant for electricity?". I could not charge them, but have higher rent. But it takes a pretty sophisticated tenant to properly account for the value there, so that would make the units appear less price competitive than they actually are. I could install a meter and charge them the same way as a power company does. But does that make me a power company? Are there a bunch of new rules I would have to follow? What do I do if someone doesn't pay the bill? I'm sure I could figure it all out, but it makes the investment less attractive, which means the price of solar relative to buying from the grid has to be even better before I would go down that route.
(edited for typos)
Just buy another electricity meter and install it after the inverter.
It seems like there are two justifications for solar if you’re on the grid. Either you want to do right by the environment (totally good, though very pricey, reason to do it!) or your electricity costs are very high. If there are others I’d love to understand them. Maybe if you’re a prepper (not making fun) then that’s another reason.
It's way easier to capacity plan with a fuel based generator though. My 35kW generator can go at least several days on a 500 gal propane tank, regardless of weather. Potentially indefinitely if propane delivery is available, but I lose phone service when the power is out beyond 4 hours, so I'd have to venture out to get signal to call, and if power is out for more than a few days, the weather is probably pretty bad and delivery may not be available.
With a solar + battery system, handling potential multiday outages, I'd be concerned about my winter where there's less than 9 hours of daylight and it's often mostly overcast, and I'm running my heatpumps to warm the house. But if I have solar/battery capacity to make that work, I'm going to have way too much capacity for most of the year.
Solar + battery for grid backup makes more sense in places with shorter duration outages and were peak electricity use is in the summer rather than the winter.
In the past year or two we’ve had an eight day power outage, five day power outage, multiple 1-2 day power outages, and who knows how many hour-ish interruptions and gasoline or propane for the generator get expensive and inconvenient running it for long periods of time.
Our main limit to how long we can comfortably survive without power is that we’re on well and septic. Without power the pumps for both aren’t running so we have no running water and no sewer. We have bottled water on hand to at least cover drinking, but if we were to just shit in a hole outside we would basically just be dumping raw sewage into our water.
Local power generation and storage is very interesting to me.
Financially, most likely he could have an even higher "ROI" with a much smaller solar battery (sized for the daily use of time shifting), plus a generator for long term outages. Unless your grid rates are such that you can buy electricity off peak, charge the battery, and then profitably sell it back to the grid (effectively operating your own small time distributed grid storage), sizing a battery to provide for multiple day outages is cost prohibitive.
If you don't have net metering, then you get bitten by needing to massively oversize your solar array to still fill the batteries on the worst case dim winter days, so that you can make it through the next night (likely powering necessary heating loads). That overproduction is then wasted on peak days unless you can find something clever to do with the excess electricity.
I'm sure there are other scenarios with time-varying electricity rates, but I'd think that calculation would be much closer to general time shifting with the backup power as an added benefit, rather than revolving around the backup power.
You'd need some pre-planning to segregate different circuits to do partial transfers and/or some smart appliances which can operate in reduced power modes. In the survival mode, maintain a critical baseload of lighting and food storage, perhaps even with some freeze-proofing heating mode that does not hit regular comfort targets. Use high-load equipment only when there is excess solar input beyond what is needed for battery maintenance etc.
You could also provide the right kind of exterior input to allow a portable generator to be added to the system in an emergency situation. This could support higher peak loads or recharge batteries when solar input is insufficient.
It's not exactly the same as just adding battery backup, because the marginal cost of adding battery backup to a solar inverter is far lower than getting an inverter for just backup purposes, and solar allows a smaller battery.
How does one stop tenants using "dodgy" chargers to charge their electric bike or whatever, and the battery bank causes a fire.?
Does your insurance cover these situations???
That said, I drive by all my properties periodically, and my property manager does annual walk through; large battery banks, excessive extension cords tacked to the walls, and solar panels sitting on the roof with wires run through a window would all get flagged in such a walkthrough, any my rental agreements allow me to require the tenant to correct unsafe conditions, which all of those are.
And I do have good insurance. There's a pervasive believe on HN that you can't get insurance that covers variations of not-to-code, not-properly-permitted, and/or not-done-by-licensed-electrician electrical installations. There very may well be insurance that excludes these things, but its easy to get insurance that covers those things, and mine does. If my tenants do dumb-ass stuff that burns the building down, I'm covered, even if that dumb-ass stuff involves electricity.
If you stop being a parasite perhaps one could afford a barn.
Someday we'll wonder why we thought it was a good idea to make the need for shelter into an investment vehicle. Until then, I hope people use your properties as they see fit.
I'm in a fortunate situation where my landlord is not a slumlord. When things need looking into, it gets taken care of in a timely manner. I do not have any issue with someone choosing to have this as a business.
It's likely the shelter will be on this earth longer than I will? We didn't make it that way, it is that way.
There's a set of circumstances that make it so. Low interest rates, being able to use leverage (borrow money, buy a house then rent it out), and higher-than-inflation price increase of houses.
Don't get me wrong, I like that dream too. I just have my thoughts about the current housing market, which to me has aspects of an investment market.
tldr: land value tax and less restrictive zoning yesterday
The manufacturers are well aware of risks, for liability reasons if nothing else, and have contained them in the uniform-electrical-code mandated manner. The system is no more risky than any other plugged-in appliance. We don't need to invent problems. Extension cords are just extension cords.
that this system won't exceed ratings is a fair point, but extension cords are not just extension cords.
All the appliances mentioned are rated to be used with appropriate extension cords, and cords are sold at retail for such use.
They're not well marked at Home Depot, you have to bother to look for the right gauge, the cables aren't even necessarily in the right place, and if you don't know jack about being an electrician, it's easy to buy a cheap 2-prong 18-gauge indoor-rated cable for use outside in a wildly inappropriate fashion. No one at Home Depot is going to stop you and ask what you're about to do with the cable.
yes, For people with half of a clue, it's possible to buy the right cable and be safe, but we have to plan for the lowest common denominator, and tell people that extension cords are just extension cords when they come in all sorts of flavors, some of which are happy to burn your house down, is irresponsible.
The store brand, which is general most prominent, gauge is color coded: 6AWG - Gray / 12AWG - Yellow / 14AWG - Pink / 16AWG - Orange. There's one exception to this where 14 AWG cable is using orange labeling normally used on 16AWG wire but that's the opposite of a safety issue.
And they have generally have the rated amperage for the length of the cable.
If you're coming from the paint department, how are you to know that the color is material? I just like orange, it's my favorite color.
My point was gauge and maximum rated amperage are on the label.
For any type of generator running exterior to interior would require rated extension cords to reduce fire risk.
The only outdoor wiring mentioned is 48V.
Ive taught a bunch of in person classes on DIY solar and I would never have published this, its asking people to get evicted or worse.
I should add, mine are all in the context of fringe living... vans, campers, boats, alleyways, etc.
Explaining that to the landlord may not be fruitful however.
That's actually one of my bigger concerns with these solar into battery stunts is where to place such a massive array of batteries such that if something caught fire it wouldn't take out my roof or other flamable stuff
Since I apparently couldn't buy one then it doesn't matter but I would need to further understand what happens <s>if</s>when those pumps fail
('liquid tracks' should have been 'liquid tanks' in my earlier comment).
[1] https://www.youtube.com/@redflow-acceleratingacarbo9077/vide...
Thermal runaway is really bad. Typical lithium rechargeable batteries can't handle overheating without starting a chain reaction: an uncontrollable thermal runaway followed by a literally inextinguishable inferno.
If you short circuit the LiFePo battery it still is going to turn into a welder. It can still start a fire. If you don't short circuit it, under normal conditions it shouldn't spontaneously combust.
1. Note: Confusingly LiFePo4 (Lithium Iron Phosphate) looks a lot like LiPo (Lithium Polymer), however, LiPo batteries are some of the most prone to fire while LiFe batteries are the least prone to fire.
> Rule 64-918 (1) further prohibits ESSs with storage capacity greater than 1 kWh or utilizing lithium-ion batteries from being installed in dwelling units.
The reasoning for that rule is "fire hazard". There is zero exceptions.
The 2024 edition has 2x 20kWh allowance in a 1h fire proof room spaced 1m apart. And you need a series of fire prevention tools like an extinguisher and such. But that is not yet implemented.
Most landlords here are pretty low maintenance (both ways) as long as you pay on time and willing to bend. Did not blink an eye when I asked to go roof WISP and drilled my own hole next to the cable line. No roof penetration so they didn’t care.
I’m thinking of asking about a weighted panel to cover the 4-9pm PG&E quadruple pricing via a LFP bank.
Yes. Insurance is a contract, and the standard insurance contracts used by nearly all insurers do not contain exclusions for permits, code violations, or things like this. They would absolutely not renew you after a loss caused by something like this, and would probably report the loss to the industry databases. Insurance companies will often try to impose liability on other parties when losses happen, but they don't sue their own customer, as the whole point of an insurance contract is that they are assuming liability for loss in exchange for your premium. (If you believe this to be otherwise, try to find a recorded instance of an insurer denying coverage for code violations or un-permitted work. I've never been able to do so, and would be very interested in reading the case study.)
If you want to be sure, just ask your insurer for a copy of your contact, and read it. They aren't that complex.
I wouldn’t condone this or any variation thereof that violates the NEC, a lot of liability is being assumed by doing this.
I realize not everyone can afford a new home but with the proper knowledge and tools you can make electrical changes to achieve your goals that can be reversed on move out.
I might have previously done things against my landlords wishes but it was done - and removed - professionally. The other option is to talk to your landlord and do it right, making it permanent upon your separation from the property.
Good point about the possibility of a roof leak and placing blame. I didn’t think of that.
Also more recently I learned that these things can vibrate. Which would not be good for a window.
You’d be better off passing a wire ribbon around the sash.
But still inspired me to perhaps to something like this that bypasses the meter and the city grid, but just a little more limited in scope than running duplicate wiring everywhere.
A more proper way to do this would be to have one self contained outdoor box rated to contain high energy batteries, have your inverter and PDU as part of that package and then plug your the panels to that. When you have a power outage go out and grab your backup battery box. This eliminates the bulk of the issues.
Although, that raises the obvious solution that you could just spend a bit more money and get one of those self contained "battery generators", which have been properly engineered and designed, and are also pretty portable.
Another thing I would add is adding some sandbags to the solar panels so that they don't fly off the roof in a high wind scenario. Theres a reason why when doing a rooftop installation code will specify this if not being directly bolted. (Technically a structural engineer will need to do a load calculation, but for this size of install the risks are minimal compared to the risks inherent in the rest of the system)
Context: I have a solar + battery system for backup power purposes. We have long enough grid outages every so often that make it worthwhile, and I need to keep the batteries charged in preparation for those outages. However, 98% of the time the batteries are charged and the solar power is just being wasted (there is no grid tie back here); I'd like to actually use it. The invertor (which is cheap chinese) can prioritize "renewable over grid" and thus use the solar during the day, but in this mode it then uses the batteries at night, and recharges them from grid when it runs them down; this means lots of battery cycles and also potential for backup to be foiled if the grid goes down at the wrong time.
But depending on your solar panel and consistent power draw, I'd maybe use the solar > battery > utility mode. It'll let you set a point to switch from battery to utility, the highest at 95%. That way when your usage is below your solar generation, you can still use the solar to charge the battery.
A bit more wear and tear on the battery, but even less solar wasted. Assuming you can handle the batteries only being at 95% if you have an outage. If your usage is less than your solar generation, could even set it lower.
I've been looking at something similar but different. My grid is fine, but I want to be able to use the batteries based on my time-of-use plan prices. I have less solar panels, but would want to charge my battery using grid power when prices are lower.
The battery setting can be configured on a timer, so you can have different cut-offs for dulifferent times of the day.
The whole thing is actually quite elegant. It turns "electricity" into this fungible thing like it was supposed to be in the first place. More pro points, you can plug in an electric-start generator and configure it to start automatically as needed in order to supplement the solar. Going further still, you can plug in a wind-turbine and have it blend it into this whole system.
Makes me wish I could install a wind turbine on my roof. A fair bit of solar, coupled with a little bit of wind suddenly makes your batteries go a really long way towards being fully off-grid capable.
https://www.mobile-solarpower.com
He has spec'd out a lot of DIY Solar Packages and lists the BoM on his website.
My understanding is commercial installs are more sensitive to efficiency than consumers. I believe it's far more economical for them to squeeze everything they can out of an acreage than it is to simply build new. Between panels losing efficiency and newer, more efficient panels coming on the market, commercial installs tend to cycle out panels well before the end of their life.
This leaves a second-hand market with some pretty crazy discounts.
These days, $1k will buy a fair bit of a China made power brick. No need for solar access — for when the power goes out in a storm and/or at night.
A big brick or several small ones is also less work; can live out of the way when not in use; and can be used when tailgating or car camping.
For food cooling a small chest freezer has broad utility and unpowered will stay cool through a moderate outage.
A good job was done considering the load on the indoor wiring, but the exposed wires on the outside of a building concern me. Typically wires have some level of insulation and/or conduit that reduces and contains the spread of fire. If wind did move the panels around, those wires could pull loose and start a fire.
SF does not perform frequent building inspection, but if an inspector saw this they would almost certainly cite that this violates building code. In the event of injury, insurance might not pay out given how this is setup.
So he's not just relying on the wind rating of the panels.
A better and perhaps code compliant way to do this (this is sometimes done this way here in NL, no idea about the US) is to bolt the panels to e.g. an aluminum frame, which you'd then hold to the roof with ballast, e.g. cinder blocks or heavy yard tiles.
Depending on the panel area, frame and amount of ballast you can easily prove that there's no way the result would move due to weather, unless you were experiencing such apocalyptic winds that the house itself would be destroyed anyway.
If you use very little on the residential schedule I think it can drop pretty low, probably around $0.15/kWh.
The lowest price on the PG&E tiered rate plan E1 (implied by the words "If you use very little ...") is $0.42/kWh. Even the most variable rate EV2A plan has an off-peak price of $0.35/kWh. I don't see any way to get a price of $0.15 kWh.
https://www.pge.com/assets/pge/docs/account/alternate-energy...
I can't work it out exactly without doing more research than is worth. As I said, the schedules are complex, maybe someone more versed in this can chime in.
Hopefully SF will finally manage to force PG&E to sell it the city's grid. I doubt it will lead to rates as low as Santa Clara's, though.
https://sfpuc.org/about-us/news/its-high-time-san-francisco-...
The $0.26/kWh is for the CARE program, which heavily discounts energy (30-35%) for low income people and families. It's not a rate available to most people.
Whereas the rates paid by those who have a municipally-owned utility (MOU) in CA (i.e. LADWP, SMUD, SVP) are actually 60% lower than those paid to investor-owned utilities (IOU) [1].
The municipal utility rates are lower because:
a) being owned by their municipalities, their primary incentive structure is to lower costs of reliable electricity for ratepayers, not to return a profit to shareholders.
b) IOUs generate profits for shareholders, and this profit is only generated - per regulation - as a percentage of capital expenditures.
c) PG&E and other IOUs must reduce the wildfire risk of their huge transmission and distribution networks, which operate in much more wildfire-prone parts of California than the municipal utilities (which are mostly urban). To achieve this, they tend to choose very expensive solutions (i.e. under-grounding transmission lines) since (b).
This results in all ratepayers in IOU territories paying much higher electricity rates, regardless of whether they are in a high fire-risk zone. If electricity rates were set based on highly localized wildfire risk, the rates would be even more divergent, sometimes in areas just a few miles apart (due to California's micro-climates). There would probably be tremendous outcry and anger, as nobody wants to pay for the risks associated with where they have chosen (or can afford to) live.
1. https://www.siliconvalleypower.com/residents/rates-and-fees
For the time being, the lowest per-kWh rate in SF is based upon the CPSF discount, time-of-usage discount, below-baseline discount, winter discount, income discount, EV adjustment, and exact schedule chosen, plus the overhead effect of fixed fees and minus the special twice-yearly climate credits. Did I miss anything? :)
I have no idea what it is, but it's somewhere between my initial figure ($0.15) and yours ($0.35.)
I did a similar project in 2003, but obviously the technology has improved a lot since then. I've previously posted some details here: https://news.ycombinator.com/item?id=36000824
The thing that stood out to me about this project was the lack of any hardware to secure the panels to the roof, which is absolutely necessary to prevent wind damage.
I specifically pick out the EV as an example because by definition my system would never need to connect to the house or the grid, so I guess all I have is a disconnected battery (powerwall) to insure.
If you go super cheap (the "$1000" system in the article), you'll be able to put a couple miles into the car in the afternoon on "level 1" charging. It's not nothing but it's not really practical for a car (but probably fine for an electric bike/moped). Also, most of the available power is unused since the battery is so small.
So you get a battery big enough to hold everything your panels can generate. You get a more powerful 240V inverter, a nice 8-10 kWh battery, and move to Southern California. With the best possible circumstances in July, you can fill up that battery every day, and add 19 miles to your car overnight.
Now you're at $10,000 for about 6,500 miles per year.
If the battery lasts 8 years (LFP can do 3000 cycles, 1 cycle per day = 8.2 years), you're paying 19¢/mile (and only if you use all of the power you generate).
Compare that to just plugging into the wall, which is 3-6¢/mile.
I agree with your conclusion that wall is better though.
Why would they want to incentivize more grid attached small solar at this point?
It would cost ~$6K. I estimate I’d save about $1500/yr from my electric bill. ROI isn’t great but most home projects have an even worse ROI so I still might do it just for kicks. Would also be nice to have a big Eco Flow battery I could use for other stuff.
I should write an article about it because I had planned to build something myself and keep all equipment outside and build a small wooden enclosure away from the house for it.
The system is even tempting to me as a homeowner not renter, but a similarly simple system that doesn't require running wires through the house might work better.
My question is if in a house a person plugs in a under rated extension cord into a normal powerpoint and connects equipment to the other end, such that the current exceeds the extension cords current rating , and a FIRE results, would the insurance company pay??? ( ie this is in a house without any of the this DIY solar. cables or battery etc) . would be interesting question.
You can 'run' a freezer for about 10-12 hours by purchasing 5-10$ worth of ice from a grocery store.
For something that happens twice in 25 years, that seems like the more pragmatic way to go?
The last major outage (due to an ice event), I hit the stores within the first hour of the outage and they were already cleaned out of water, propane, ice, and getting rapidly cleaned out of other supplies.
If it was an ice event, why would you have to travel to get ice?
I've never seen anything like it. Individual blades of grass were embedded in solid capsules of ice. I regret not taking the time to get the camera out and do a bunch of photography, but I had my hands full the entire time.
A few nights later, the ice had barely begun to thaw, and then it refroze and then started snowing. I stood outside my home for a bit in the darkness, and listened to the sounds of tree limbs cracking, breaking, snapping, and crashing, like a steady rhythm, for a while. Just, "boom, crash. ... boom, crash. ... boom, crash. ..."
The bell curve for outages seemed to be a few days at the least, to about 5 to 10 days for most, to about three weeks for some in outlying areas. You can find some reasonable articles by searching for "2024 oregon ice storm".
In any case, point was, whatever supplies you think you'll need for an extended power outage are likely to become scarce really quickly.
Local issues don’t cause 4 day outages it’s stuff like hurricanes or major grid infrastructure issues from construction mishaps.
Ex: https://islandfreepress.org/outer-banks-news/07272018-ayeara...
A self-critique: power outage isn't going to occur without notifying the person, except for maybe being out of town. That said, one less problem to solve in response to rare, anticipatable event.
So you are trading between different categories of disasters.
I wonder what the cost/benefit calculation is for that v.s. an entire solar backup system.
But the commercial product is cheap enough to buy if it's going to be your backup plan.
If you have net metering, being able to push power back into the grid is a major plus.
But he's in San Francisco and California does not have net metering. I've been considering doing something like this as any grid-tied system is about $3/W for power, plus $500/kWh for storage. But an off-grid system done on your own is about $0.60/W plus $200/kWh for storage.
Throw one in every room and between appliances like the fridge or oven. Now you have a UPS for your whole house and the cheapest energy rates throughout the day.
https://www.amazon.com/dp/B08G81TKC6?ie=UTF8&th=1&linkCode=s...
Also, $190/kWh is so cheap. Its hard to believe how fast costs are falling for energy storage.
I keep a couple charged, but with nothing plugged in. I sometimes plug things in before a major storm, planned outage, or after an unplanned one.
Are there equivalent all-in-ones that would provide 230/240V AC for use in Australia/New Zealand?
This looks to be the same or similar product for 220v: https://a.aliexpress.com/_EwlP4Cf
I can’t imagine a landlord in existence that wouldn’t throw a fit about something like this.
All 50 states have adopted NFPA 70, the National Electric Code, and the linked article shows a bunch of things that absolutely DO require a permit and would absolutely FAIL to be approved:
First and foremost, running bare high voltage DC wires through an open window is in violation of a pile of building codes and very dangerous. The linked solar panels have an open circuit voltage of 64.8V, so with four of them in parallel there can be 260V of direct current. This can and will kill you, especially if you touch it in such a way where muscular tetanus prevents you from releasing the cable.
Electrical extension cords are intended to be temporary, and the article's use of them violates a bunch of codes. Here are some of the relevant ones:
400.10 Uses Permitted
(A) Uses
Flexible cords and flexible cables shall be used only for the following:
(1) Pendants.
(2) Wiring of luminaires.
(3) Connection of portable luminaires, portable and mobile signs, or appliances.
(4) Elevator cables.
(5) Wiring of cranes and hoists.
(6) Connection of utilization equipment to facilitate frequent interchange.
(7) Prevention of the transmission of noise or vibration.
(8) Appliances where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance and repair, and the appliance is intended or identified for flexible cord connection.
(9) Connection of moving parts.
(10) Where specifically permitted elsewhere in this Code.
(11) Between an existing receptacle outlet and an inlet, where the inlet provides power to an additional single receptacle outlet. The wiring interconnecting the inlet to the single receptacle outlet shall be a Chapter 3 wiring method. The inlet, receptacle outlet, and Chapter 3 wiring method, including the flexible cord and fittings, shall be a listed assembly specific for this application.
400.12 Uses Not Permitted
Unless specifically permitted in 400.10, flexible cables, flexible cord sets, and power supply cords shall not be used for the following:
(1) As a substitute for the fixed wiring of a structure
(2) Where run through holes in walls, structural ceilings, suspended ceilings, dropped ceilings, or floors
(3) Where run through doorways, windows, or similar openings
(4) Where attached to building surfaces
Exception to (4): Flexible cord and flexible cable shall be permitted to be attached to building surfaces in accordance with 368.56(B).
(5) Where concealed by walls, floors, or ceilings or located above suspended or dropped ceilings
Exception to (5): Flexible cord and flexible cable shall be permitted if contained within an enclosure for use in Other Spaces Used for Environmental Air as permitted by 300.22(C)(3).
(7) Where subject to physical damage
400.17 Protection From Damage
Flexible cords and flexible cables shall be protected by bushings or fittings where passing through holes in covers, outlet boxes, or similar enclosures.
300.3 Conductors
(A) Single Conductors
Single conductors specified in Table 310.104(A) shall only be installed where part of a recognized wiring method of Chapter 3.
300.4 Protection Against Physical Damage
Where subject to physical damage, conductors, raceways, and cables shall be protected.
300.6 Protection Against Corrosion and Deterioration
Raceways, cable trays, cablebus, auxiliary gutters, cable armor, boxes, cable sheathing, cabinets, elbows, couplings, fittings, supports, and support hardware shall be of materials suitable for the environment in which they are to be installed.
300.11 Securing and Supporting
(A) Secured in Place
Raceways, cable assemblies, boxes, cabinets, and fittings shall be securely fastened in place.
300.12 Mechanical Continuity — Raceways and Cables
Raceways, cable armors, and cable sheaths shall be continuous between cabinets, boxes, fittings, or other enclosures or outlets.
310.10 Uses Permitted
(C) Wet Locations
Insulated conductors and cables used in wet locations shall comply with one of the following:
Be moisture-impervious metal-sheathed
Be types MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THWN, THWN-2, XHHW, XHHW-2, or ZW
Be of a type listed for use in wet locations
(D) Locations Exposed to Direct Sunlight
Insulated conductors or cables used where exposed to direct rays of the sun shall comply with (D)(1) or (D)(2):
Conductors and cables shall be listed, or listed and marked, as being sunlight resistant
Conductors and cables shall be covered with insulating material, such as tape or sleeving, that is listed, or listed and marked, as being sunlight resistant
110.3 Examination, Identification, Installation, Use, and Listing (Product Certification) of Equipment
(B) Installation and Use
Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.
Other various code sections that this would fail:
110.8 Wiring Methods
Only wiring methods recognized as suitable are included in this Code. The recognized methods of wiring shall be permitted to be installed in any type of building or occupancy, except as otherwise provided in this Code.
110.12 Mechanical Execution of Work
Electrical equipment shall be installed in a neat and workmanlike manner.
110.13 Mounting and Cooling of Equipment
(A) Mounting
Electrical equipment shall be firmly secured to the surface on which it is mounted. Wooden plugs driven into holes in masonry, concrete, plaster, or similar materials shall not be used.
110.26 Spaces About Electrical Equipment
Access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment.
(A) Working Space
Working space for equipment operating at 1000 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the dimensions of 110.26(A)(1), (A)(2), (A)(3), and (A)(4) or as required or permitted elsewhere in this Code.
(B) Clear Spaces
Working space required by this section shall not be used for storage. When normally enclosed live parts are exposed for inspection or servicing, the working space, if in a passageway or general open space, shall be suitably guarded.
(E) Dedicated Equipment Space
All switchboards, switchgear, panelboards, and motor control centers shall be located in dedicated spaces and protected from damage.
(1) Indoor
Indoor installations shall comply with 110.26(E)(1)(a) through (E)(1)(d).
(a) Dedicated Electrical Space. The space equal to the width and depth of the equipment and extending from the floor to a height of 1.8 m (6 ft) above the equipment or to the structural ceiling, whichever is lower, shall be dedicated to the electrical installation. No piping, ducts, leak protection apparatus, or other equipment foreign to the electrical installation shall be located in this zone.
(2) Outdoor
Outdoor installations shall comply with 110.26(E)(2)(a) through (c).
(a) Installation Requirements. Outdoor electrical equipment shall be the following:
(1) Installed in identified enclosures
110.27 Guarding of Live Parts
(A) Live Parts Guarded Against Accidental Contact
Except as elsewhere required or permitted by this Code, live parts of electrical equipment operating at 50 to 1000 volts, nominal shall be guarded against accidental contact by approved enclosures or by any of the following means:
(1) By location in a room, vault, or similar enclosure that is accessible only to qualified persons.
(3) By location on a balcony, gallery, or platform elevated and arranged so as to exclude unqualified persons.
(4) By elevation above the floor or other working surface as follows:
A minimum of 2.5 m (8 ft) for 50 volts to 300 volts between ungrounded conductors
(B) Prevent Physical Damage
In locations where electrical equipment is likely to be exposed to physical damage, enclosures or guards shall be so arranged and of such strength as to prevent such damage.The quoted regulations govern construction. Residents have much greater latitude. All the appliances mentioned are approved for use with rated extension cords.
The regs (and by extension a fire marshal) would probably be unhappy about the extension cord, but a. 'everyone does it'[2], b. 'surge protecting' cords are generally exempt (at least in my jurisdictions), and c. trivially rectified by hard wiring one or both ends of the extension cord to hard wire or create a 'wire + receptacle'.
[0]Current limitations, watt-hr limitations, etc. may apply in this case.
[1]Obligatory disclaimer: not advice, follow your local regulations, etc.
[2]The response would be a 'please fix this' and not fines or worse.
Your fire marshal might have passed 5V cabling duct taped to a wall, but it would be in violation of 720.11:
720.11 Mechanical Execution of Work
Circuits operating at less than 50 volts shall be installed in a neat and workmanlike manner. Cables shall be supported by the building structure in such a manner that the cable will not be damaged by normal building use.>Circuits operating at less than 50 volts shall be installed in a neat and workmanlike manner. Cables shall be supported by the building structure in such a manner that the cable will not be damaged by normal building use.
The only possible violation of 720.11 for duct taping <50V cables to walls I can see is 'neat and workmanlike' which is vague at best; there is nothing intrinsically 'un-neat' about an attachment method unless maybe using like literal chewing gum or something else absurd or just categorically unfit for purpose. I'm hardly going to call it best practice, but duct taping a (small to modest-sized) zip-tied bundle of low voltage cables to say route it up and around a door is perfectly cromulent in my experience.
Likewise I'd feel perfectly comfortable (from both a safety and code/inspection perspective) supergluing cables to dry wall (on the more absurd end), or p clamp'ing w/ drywall screws, or using adhesive zip tie mounts, etc.
> DO NOT DO THIS!
Flexible cords and flexible
cables shall be used only for
the following: [...] (9)
Connection of moving parts.
The rules don't specify that you must have a reason that isn't dumb to make those parts move.
The "400.12 Uses Not Permitted" section gives the list in "400.10" a blanket exemption ("unless specifically permitted in 400.10"), and that's the section that would forbid running the wires through a window.
Even if you managed to make the panels movable, this would fail 690 of the NEC:
690.31 Wiring Methods
(A) Wiring Systems
All raceway and cable wiring methods included in this Code, other wiring systems and fittings specifically listed for use in PV arrays, and wiring as part of a listed system shall be permitted. Where wiring devices with integral enclosures are used, sufficient length of cable shall be provided to facilitate replacement.
Where PV source and output circuits operating at voltages greater than 30 volts are installed in readily accessible locations, circuit conductors shall be guarded or installed in Type MC cable or in raceway. The ampacity of 105°C (221°F) and 125°C (257°F) conductors shall be permitted to be determined by Table 690.31(A)(b). For ambient temperatures greater than 30°C (86°F), the ampacities of these conductors shall be corrected in accordance with Table 690.31(A)(a).0Even if that's the case it seems you could circumvent the rest by using lower voltage coming from the panels into the house.
But still, the mentality in this thread made me double-check if i'm on hacker news or bureaucrat news.
There is no "Uber, but for electricians", for a reason. :)
- Install this equipment in a permanent manner consistent with its listings and all applicable codes. "Off-grid" does not mean "do whatever you want", it means you aren't connected to a fixed grid.
- Buy equipment that is designed (and listed) for portable PV storage. This would most commonly be used for RVs and the like, and would look more like a generator than a house panel. You still don't get to drape extension cords all over your home in lieu of permanent wiring if you do this.
- Start a company, design a product that can allow temporary whole-circuit backups without transfer switches and all the usual stuff, and somehow convince a NRTL to list it. Good luck.
I don't have any loads setup on mine because I don't want to run cables everywhere like that, so my battery just sits fully charged until I need it.
Solar cells need ventilation on their undersides, and without it will rapidly be damaged (i.e. become more inefficient). Long-term, water trapped underneath may encourage shinglerot.
I have lights with cables rated at well under 3A, they plug into the same outlet that a 10A cable can plug into.
How do you stop a fault which draws 7A?
No, usually not, though better power strips will have one. But you don't need to go over the specified amps to cause a fire, there are multiple places that could overheat - extension cable, connections, solder points - while still being under the fuse rating if this thing is running at max power for a long time. The main job of a fuse is to protect against power surges / short circuits.
I don't notice these where I live, because they literally never happen. Are there really places in the first world in 2024 where blackouts still happen frequently?
Even people living in parts of California suffering under the reign of PG&E and their "power safety" shutoffs during potential fire events don't really experience prolonged, frequent outages, but they are a memorable nuisance (speaking as someone who lived in one of those areas).
That said, if you haven't experienced this yet, that's great, but it's likely that you will in the not-too-distant future. Power infrastructure almost everywhere is getting a bit wobbly for a couple of reasons: much of it is well beyond its originally designed lifetime, much of it hasn't been maintained as well as it should have been, and we are currently living through the disruptive effects of an increasingly unstable climate that have been predicted for decades. If your power comes from hydro, then freshwater ecosystems are experiencing deeper and longer drought cycles and the dam that provides that power is probably getting a bit old. If you live in a hurricane area, you're eventually going to get hit by a really bad one. If you live in an area that gets cold, you'll eventually get hit by a severe ice storm. If you live near a wooded area, it's going to burn. If you live deep in an urban setting and your power comes from a nuclear plant and everything has been well enough funded end-to-end to keep it in good working order, then congratulations, you probably won't experience any of these events directly.
But a lot of other people are, regardless of who they or their neighbors vote for.
What's not normal is that last week, our utility (Xcel Energy) decided to preemptively shut off power to 55,000 customers to reduce risk before a forecasted wind event with high fire-risk[2]. They had intended to restore power the next day, but some went without power for a couple days.
The communication and execution of the shutdown seemed poor, and the infrastructure problems that led to the shutdown are still here. The impression I have from comments in local groups is that they are trying to avoid liability and have not adequately invested in fixing shoddy infrastructure that is going to be safe here. People are expecting regular shutoffs to become the new normal. Wind storms aren't going away, fixing the infrastructure would take a long time, and people don't think Xcel is interested in spending the money, even though they can likely afford to.
This has definitely left me thinking about a DIY battery+solar solution to keep my heating system running, as well as fridge/freezers.
[1] https://en.wikipedia.org/wiki/Marshall_Fire [2] https://www.cpr.org/2024/04/08/for-the-first-time-a-colorado...
It’s not just power - we had a forest fire one year that burned a microwave tower & killed our cell phones _and_ internet for a week. The local businesses struggled for a day or two, because no one really carries cash anymore.
I should add that kind of like the OP, I added an enphase LiFePO4 house battery and panels. They’ll keep critical loads running basically indefinitely, which has been a welcome change. We have gas heat, but I used to get nervous in the winter when the power went out (our boiler requires electricity to run).
I'm worse off than many, because I live on an island, and my electric service comes in across the water from a penisula. There's an awful lot of non-redundant paths through the penisula. On the island, there is no redundancy either, but there is a plan to create a ring between the three substations, which should help.
Most of my outages are only a few seconds. At the substation, they have reclosers [1], circuit breakers that will open when shorts or abnormal currents are detected, and then quickly reclose (thus the name) as many shorts are transient.
But when a tree falls on the line, that needs a truck rolled out to investigate, and often another one or two to repair. And conditions are similar across the area, so if one tree is on a line, there will be many. My local infrastructure is low priority because it serves few customers.
Ice storms are pretty nasty too, because then you've got potentially a lot more trees falling, and also hazardous road conditions that prevent or slow repair work.
When I lived in other places, power outages were much more rare. I would have never considered a whole house generator in those places, but I have one here and most of the houses I looked at had them. I would certainly install one if there wasn't one already.
https://en.wikipedia.org/wiki/January_1998_North_American_ic...
https://www.timesunion.com/weather/article/capital-region-ad...
Most of the US Northeast is at risk of major power outages during strong storms, especially early/late nor'easters which bring ice and heavy wet snow.
I guess you could say the US is not a first world country if you want to throw shade, but I'm not buying it.
Add in global warming bringing excessive intense rain storms to soften up the ground, and wind storms happening several times a year, and the result is we lose power at least once or twice a year. Some neighbors in very heavily wooded roads lose power 5+ times a year.
Funny enough, it seems to put the nearest cell phone antenas down as well as I can't even rely on tethering my mobile phone connection to work from home.
I had two 3 minute+ power drops yesterday. The local university lost power for 10+ hours, and scientists -80C freezers had to be emergency evacuated to other locations.
This is 100% a fire hazard and would get your home insurance voided.