> 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.
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.
- 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.
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. :)
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:
You absolutely cannot and should not run bare wires through a window. This manages to violate basically all of Chapter 3 of the NEC: Both the solar panels and the inverter are listed products and are required to be installed in accordance with their listings. In particular, this means they must be permanently fastened to the structure in the manner of the manufacturer's instructions. The solar panels must be fastened to the structure in a way that resists wind and weather loads. There are entire sections of the NEC and various IBC codes devoted to this.Other various code sections that this would fail: