New NEC code makes it impossible for DIY systems to be compliant

[hankcurt]

I signed up for the free access to the NFPA codes at https://www.nfpa.org/Codes-and-Standards/All-Codes-and-Standards/Free-access

I think the result of these changes will largely depend upon your code enforcement AHJ. The language in article 690 defines the parts of a photovoltaic system and it shows the ESS (electrical storage system) as separated from the PV and inverter.

Article 706 says that an ESS may include a charge controller or inverter, but also states it doesn't cover uninterruptible power systems (which obviously contain a charge controller and inverter), and the differentiation appears to be if the batteries are used to normally power the system or are only used to power the system during a power failure.

Then there is article 480 on storage batteris, which requires storage batteries to be listed unless they are lead acid batteries (so a little fear of the unknown here). This article might be useful to people assembling battery packs as it covers terminal connection practices, corrosion, conductive battery cases and voltage drop requirements. So even if it doesn't apply to you, it might steer you towards best practices. So how do you know if you have a PV system with storage batteries or an ESS system? I think article 690 leans towards calling batteries connected to a PV system an ESS, but depending upon the complexity of your system, you might be able to call them storage batteries.

Also, article 706 on electrical storage systems goes still goes into all the detail of how an ESS has to be constructed (disconnects, over current protection, wire ampacity, etc.), so might your AHJ say the ESS system listing applies to manufactured systems, but the method of construction and parts requirements apply to DIY constructed systems. I suppose it will depend on their attitude and level of interest.

 

[hankcurt]

Maybe if I didn't call the building department and ask about UL batteries I could be a rebel too.
I'm paying $850 including shipping for UL listed batteries. And they aren't going to waste.

@ArthurEld, can I ask which batteries you decided to purchase?

 

[SolarBro]

Well Im using mpp units, so im not totally code accurate anyway.

There is buildings with 80s AL wiring still operating just fine. Staying safe is relative.

 

[ArthurEld]

@ArthurEld, can I ask which batteries you decided to purchase?

Universal Ub121000 12V, 100Ah (20Hr) Sealed Agm

Click here for Universal Battery Universal Ub121000 12V, 100Ah (20Hr) Sealed Agm from altE® - Making Renewable Do-able since 1999.

www.altestore.com

I bought 4 of them. They were 10% off last week.

 

[Ampster]

People becoming grid independent is the last thing the .gov wants.

I am more optimistic. It also depends on which government you are talking about. I hear rumors there may be a new government soon in Washington. Out here on the left coast, California is subsidizing the cost of batteries in an effort to make the grid more resilient.
I am still going to take the Federal Tax credit and pull a permit from my local building department under the old rules ASAP. My next project may have to be in an RV.

 

[Ampster]

I think the result of these changes will largely depend upon your code enforcement AHJ.

Thats good input. In California the AHJ for prefabricated homes is the state government. There has recently been an increase in people putting these into their backyard as accessory dwelling units. Otherwise known as mother in law units they are also used as VRBO or AirBNB short term vacation rental units in areas like mine where there is a lot of tourist visits. When one door closes, another one opens.

 

[Hedges]

Maybe if I didn't call the building department and ask about UL batteries I could be a rebel too.
I'm paying $850 including shipping for UL listed batteries. And they aren't going to waste.

The batteries are probably "UL Recognized".
Close but no cigar?

Obviously lithium batteries can make it relatively easy to start a fire.
Ideally we'd get to the point where there is a standard for a lithium cell (or bank of cells), that both BMS and cells are listed as meeting.
Then we could mix & match within those. There should just be parameters of the cell to be entered in the BMS.

Is an ESS a battery together with charge controller? And with inverter? Or just a stack of lithium cells with BMS?
Is a bank of of AGM (or FLA) an ESS? it doesn't require a BMS.

 

[hankcurt]

Is an ESS a battery together with charge controller? And with inverter? Or just a stack of lithium cells with BMS?
Is a bank of of AGM (or FLA) an ESS? it doesn't require a BMS.

From NEC 2020 article 690 - PV system, the ESS doesn't include the inverter





From NEC 2020 article 706 - ESS might or might not include the charge controller and inverter

I think there are too many design variations to make an all encompassing statement.

 

[Ampster]

Solutions are beginning to emerge.

 

[ArthurEld]

The batteries are probably "UL Recognized".
Close but no cigar?

Obviously lithium batteries can make it relatively easy to start a fire.
Ideally we'd get to the point where there is a standard for a lithium cell (or bank of cells), that both BMS and cells are listed as meeting.
Then we could mix & match within those. There should just be parameters of the cell to be entered in the BMS.

Is an ESS a battery together with charge controller? And with inverter? Or just a stack of lithium cells with BMS?
Is a bank of of AGM (or FLA) an ESS? it doesn't require a BMS.

You are correct.
I'll mention it to AltE. If no cigar I'll have to go with Bob's plan.

It would be nice for the pre approval to go smooth.

I'll get through it even if I have to buy a NEC 2020 Article 690 approved ESS. ?

 

[Hedges]

I'll get through it even if I have to buy a NEC 2020 Article 690 approved ESS. ?

Then you'll have to install an explody lithium battery instead of an (almost) intrinsically safe AGM.

I suppose either LiFePO4 or AGM, if severely abused electrically, can become a fire hazard.
(but so can a piece of copper wire, ergo fuses/breakers with sufficient AIC rating.)

Maybe my solution would be to connect four, 20A 12V batteries in series and wire that to my 23 kW of Sunny Island.
Perhaps I would park a golf cart or forklift nearby. With an Anderson connector (or four) for charging the batteries, of course.

The "batteries optional" hybrid inverters may be the easiest to install and get permitted with a wink.

Another way would be an automatic transfer switch with plug for generator.
And maybe a car with V2H in the driveway.

 

[Ampster]

Ideally we'd get to the point where there is a standard for a lithium cell (or bank of cells), that both BMS and cells are listed as meeting.

And I would add that there needs to be some recognition of fire risk between chemistries. In other words Lipo should not even be considered unless housed in a concrete bunker. NCA and NMC need to have mitigation like in Tesla Powerwalls and other UL approved types. LFPs can have a different standard. The thing that is ironic is the lack of rules around Pb chemistries some of which do give off explosive hydrogen gas.

 

[ArthurEld]

I think most of our lithium batteries are pretty safe.
I see a lot of systems with old corroded 12V lead acid batteries that don't look very safe.
And people using way too many amps on 12V systems.

 

[FilterGuy]

Solutions are beginning to emerge.

I am not sure if you mean solutions for the DIYer or solutions in the broader market.

It is is always the case that when code changes solutions start showing up in the market. In fact, I have never seen a code change that did not have at least one solution (all be it an expensive solution). The various suppliers have a capitalistic interest in providing solutions. Over time the incremental cost of the new code tends to go down as the competition increases.

Unfortunately, the NFPA has no interest or incentive to address the DIY market. However, solutions for the larger market typically have beneficial trickle-down to the DIY market.

Then you'll have to install an explody lithium battery instead of an (almost) intrinsically safe AGM.

I suppose either LiFePO4 or AGM, if severely abused electrically, can become a fire hazard.
(but so can a piece of copper wire, ergo fuses/breakers with sufficient AIC rating.)

And I would add that there needs to be some recognition of fire risk between chemistries. In other words Lipo should not even be considered unless housed in a concrete bunker. NCA and NMC need to have mitigation like in Tesla Powerwalls and other UL approved types. LFPs can have a different standard. The thing that is ironic is the lack of rules around Pb chemistries some of which do give off explosive hydrogen gas.

Yes, this goes to the broader issue I have seen: All lithium chemistries are lumped under the "They can explode" category. (Example: LiFePo4 is considered just as dangerous as any other lithium chemistry for shipping) Hopefully over time they will start differentiating between the chemistries, but it might be a while. (It is kinda like "anything with the word nuclear is horrible horrible Horrible....." That is why they changed the name of Nuclear Imaging to Magnetic Resonance Imaging or MRI)

 

[Ampster]

The "batteries optional" hybrid inverters may be the easiest to install and get permitted with a wink.

That is my fallback plan.

Another way would be an automatic transfer switch with plug for generator.
And maybe a car with V2H in the driveway.

I have been skeptical of V2H in the past but this new development has changed my perspective. I also like the idea of a hopped up golf cart with 48 LF 280s. Or an electric tractor.

 

[ArthurEld]

That is my fallback plan.

I have been skeptical of V2H in the past but this new development has changed my perspective. I also like the idea of a hopped up golf cart with 48 LF 280sn. Or an electric tractor.

People drive golf carts all over in Florida. They're legal on the streets in a lot of towns.
And people have high dollar golf carts. lol
That tractor would probably need wheelie bars.

 

[Ampster]

I am not sure if you mean solutions for the DIYer or solutions in the broader market

A little of both as discussed down thread. I am hopeful as this gets better defined and as overall battery manufacturing capacity increases that the cost of "UL approved" ESS devices comes down. There will always be a price difference between UL approved and commodity devices like we have seen in the inverter market.

 

[Ampster]

That tractor would probably need wheelie bars.

LOL. I do see some tractors with weights on their wheels to improve traction.

 

[Dzl]

If anyone is a member (I believe @SolarQueen is) or inclined to join, Mike Holt's forum might be a good place to gather some context. There are many there that are very code savvy, and I think a few that have a role in steering the code.

 

[ArthurEld]

AltE is doing my planning with Structural and Electrical engineering 2 copies sealed and stamped.