James: Your on-grid home or business already has a quick and efficient means of disconnecting power by a random person: If you have a non-CT meter it’s a matter of clipping the meter tag and pulling the meter. If there is a CT meter, there will be a switch to flip.
Fortunately off-grid homes do not usually have random people on the premises. I have always felt it beyond my expertise to second-guess what first responders require to perform their jobs safely. Most code requirements do add expense and inconvenience. However most requirements seem well founded in logic. When I travel in third world countries or read about building system failures, I personally appreciate the codes we have. William On Sat, Jan 28, 2023 at 4:58 PM James Jarvis <[email protected]> wrote: > It would be nice if the decision was up to the owner / occupant of the > property. I, for one, do not want any random person to be able to turn off > my house or business with the flick of a switch. I feel strongly that there > is far too much fear mongering in NEC with relation to renewable energy. > > -James Jefferson Jarvis > APRS World, LLC > +1-507-454-2727 > http://www.aprsworld.com/ > > > On Sat, Jan 28, 2023 at 6:22 PM William Miller via RE-wrenches < > [email protected]> wrote: > >> Esteemed wrenches: >> >> Well if my house is on fire and the entry of fire responders is delayed >> for lack of a disconnect, I choose having the disconnect. I can worry about >> the charge controllers later. >> >> Others may prioritize their charge controller over their homes… >> >> Put a cable-tie lock in the closed position to discourage kids from >> messing with it. Test it only after dark. >> >> William >> >> On Sat, Jan 28, 2023 at 2:32 PM William Bryce < >> [email protected]> wrote: >> >>> All >>> >>> One thing that no one is talking about is what happens to the MPPT >>> charge controllers when the Battery Disconnect trips when the charge >>> controllers are under full load. >>> Many will blow up. Try turning off the battery breaker on a SolaArk >>> when the charge controllers are maxed, and see if you get lucky. >>> >>> On Sat, Jan 28, 2023 at 3:27 PM William Miller via RE-wrenches < >>> [email protected]> wrote: >>> >>>> Jeremy: >>>> >>>> >>>> >>>> Thanks for posting the code references for those that had never looked >>>> them up. >>>> >>>> >>>> >>>> Chris: >>>> >>>> >>>> >>>> What do you mean by “a disconnect for AC wiring, not specific to which >>>> or both panel types”? >>>> >>>> >>>> >>>> All: >>>> >>>> >>>> >>>> Code references are handy when receiving edicts from building >>>> officials, but not required, IMHO, for two reasons: The contractor should >>>> already be versed in the codes and, building departments can mandate their >>>> own requirements above and beyond the code. >>>> >>>> >>>> >>>> It may seem redundant to require an AC disconnect for premise wiring as >>>> well as a DC battery disconnect. In most cases if you disconnect the >>>> inverter from the batteries the AC power goes off. However if the >>>> generator is running at the time, some battery inverters can operate when >>>> disconnected from batteries. So to completely de-energize all components >>>> of an off-grid home you need to disconnect the generator and the battery >>>> leads. >>>> >>>> >>>> >>>> In this case the home is required to have fire sprinklers. There is >>>> pressure pump to provide flow to these fire sprinklers-- said pump being >>>> powered by the inverter/battery system. I am going to apply for a waiver >>>> to remove the DC disconnect requirement on the grounds that the pressure >>>> pump is essential fire suppression equipment. Instead I will propose to >>>> supply an AC disconnect (meeting all requirements for accessibility and >>>> marking) that will disconnect all premise wiring except the pressure pump. >>>> >>>> >>>> >>>> By the way, I will of course be trying to apply the logic that the >>>> voltage specification is for nominal battery voltage and this project >>>> having a nominal 48 volt bank does not require the battery disconnect. >>>> >>>> >>>> >>>> I will let the group know what response I receive. Regardless of how >>>> this works in this jurisdiction, I think these are both valid arguments >>>> worth trying in any jurisdiction requiring the battery disconnect. Some >>>> officials are amenable to dialog and negotiation and some are less so. >>>> >>>> >>>> >>>> >>>> >>>> William Miller >>>> >>>> >>>> >>>> Miller Solar >>>> >>>> 17395 Oak Road, Atascadero, CA 93422 >>>> >>>> 805-438-5600 >>>> >>>> www.millersolar.com >>>> >>>> CA Lic. 773985 >>>> >>>> >>>> >>>> >>>> >>>> *From:* RE-wrenches [mailto:[email protected]] *On >>>> Behalf Of *Jeremy Rodriguez via RE-wrenches >>>> *Sent:* Saturday, January 28, 2023 10:12 AM >>>> *To:* [email protected]; RE-wrenches >>>> *Cc:* Jeremy Rodriguez >>>> *Subject:* Re: [RE-wrenches] Remote battery disconnects >>>> >>>> >>>> >>>> >>>> >>>> *2020 Code Language:* >>>> >>>> *480.7 DC Disconnect Methods.* >>>> >>>> *(A) Disconnecting Means.* *A disconnecting means shall be provided >>>> for all ungrounded conductors derived from a stationary battery system with >>>> a voltage over 60 volts dc. A disconnecting means shall be readily >>>> accessible and located within sight of the battery system.* >>>> >>>> *N* *(B) Emergency Disconnect.* *For one-family and two-family >>>> dwellings, a disconnecting means or its remote control for a stationary >>>> battery system shall be located at a readily accessible location outside >>>> the building for emergency use. The disconnect shall be labeled “EMERGENCY >>>> DISCONNECT”.* >>>> >>>> *N **(C) Disconnection of Series Battery Circuits.* *Battery circuits >>>> exceeding 240 volts dc nominal between conductors or to ground and subject >>>> to field servicing shall have provisions to disconnect the series-connected >>>> strings into segments not exceeding 240 volts dc nominal for maintenance by >>>> qualified persons. Non-load-break bolted or plug-in disconnects shall be >>>> permitted.* >>>> >>>> >>>> >>>> Jeremy Rodriguez >>>> >>>> Solar Installation / Design >>>> >>>> All Solar, Inc. >>>> >>>> 1453 M St. >>>> >>>> Penrose Colorado 81240 >>>> >>>> >>>> >>>> Sent by Jeremy's iPhone. Sorry for typos and shorthand. >>>> >>>> >>>> >>>> On Jan 28, 2023, at 7:28 AM, Christopher Warfel via RE-wrenches < >>>> [email protected]> wrote: >>>> >>>> >>>> >>>> Seems confusing that the AHJ is requiring a disconnect for AC wiring, >>>> not specific to which or both panel types, and then a dc disconnect with no >>>> code reference. Was trying to convey a reasonable, safe approach. A lot >>>> of bad information from fire department solar consultants making a lot of >>>> money fear mongering, which has led to this type of situation. Chris >>>> >>>> On 1/27/2023 3:35 PM, William Miller via RE-wrenches wrote: >>>> >>>> Glenn: >>>> >>>> >>>> >>>> As I wrote, a DC disconnect is required. Here is an excerpt from the >>>> Q&A with the building official: >>>> >>>> >>>> >>>> 4. Will you be requiring an external disconnect to disconnect the AC >>>> output of the inverter system from premise wiring? >>>> >>>> Yes, as required per 230.85 >>>> >>>> 5. Will you be requiring an external disconnect to disconnect >>>> batteries from the inverters? >>>> >>>> Yes >>>> >>>> >>>> >>>> If the DC disconnect was not required I would not be wasting everyone’s >>>> time with my post. I try to be careful about that, researching on my own >>>> before posting and trying to make my questions very clear. I also try not >>>> to embarrass myself with dumb questions, but that does happen occasionally… >>>> >>>> >>>> >>>> William >>>> >>>> >>>> >>>> Miller Solar >>>> >>>> 17395 Oak Road, Atascadero, CA 93422 >>>> >>>> 805-438-5600 >>>> >>>> www.millersolar.com >>>> >>>> CA Lic. 773985 >>>> >>>> >>>> >>>> >>>> >>>> *From:* RE-wrenches [mailto:[email protected]] *On >>>> Behalf Of *Glenn Burt via RE-wrenches >>>> *Sent:* Friday, January 27, 2023 11:46 AM >>>> *To:* William Miller via RE-wrenches >>>> *Cc:* Glenn Burt >>>> *Subject:* Re: [RE-wrenches] Remote battery disconnects >>>> >>>> >>>> >>>> Does the AHJ really want the batteries disconnected from conductors, or >>>> does he really just want the inverters to stop operating and producing AC >>>> within the house? >>>> >>>> Obviously there is a big difference here and it may be changing as the >>>> code evolves. >>>> >>>> >>>> >>>> -Glenn >>>> >>>> Sent from my 'smart'phone, so please excuse typos and spelling errors. >>>> >>>> >>>> >>>> ------ Original message------ >>>> >>>> *From: *William Miller via RE-wrenches >>>> >>>> *Date: *Fri, Jan 27, 2023 2:26 PM >>>> >>>> *To: *RE-wrenches; >>>> >>>> *Cc: *William Miller; >>>> >>>> *Subject:*[RE-wrenches] Remote battery disconnects >>>> >>>> >>>> >>>> Friends: >>>> >>>> >>>> >>>> We have a large-ish residential off-grid system install coming up. The >>>> AHJ has said they will require a remote battery disconnect. I suspect >>>> there will be fire sprinkler controls and a pressure pump that would become >>>> inoperable if this system were engaged. In this case we will apply for a >>>> waiver. >>>> >>>> >>>> >>>> The last time this was discussed here as far as I can find was October >>>> of 2020. At that time no one suggested any specific battery disconnect >>>> equipment. >>>> >>>> >>>> >>>> To further clarify my needs: There will be 4 or 5 Radian 8048 >>>> inverters (5 or 6 4/0 battery circuits, ~350A each) and two 175 amp PV >>>> recombiner outputs. That is 6 poles of high amperage DC disconnects. >>>> >>>> >>>> >>>> The battery array will be either a UnigyII VRLA or a lithium of a brand >>>> yet to be determined. In the case of lithium we will look for a system >>>> that can remotely enable a BMS shutdown. In the case of a VRLA lead-acid, >>>> we will not have that luxury. >>>> >>>> >>>> >>>> I have done some considerable research and have not found viable, high >>>> amperage, remotely activated shutdown equipment. >>>> >>>> >>>> >>>> I am wondering what hardware others may be using to achieve remote >>>> battery disconnecting in these types of cases.. >>>> >>>> >>>> >>>> William >>>> >>>> >>>> >>>> Miller Solar >>>> >>>> 17395 Oak Road, Atascadero, CA 93422 >>>> >>>> 805-438-5600 >>>> >>>> www.millersolar.com >>>> >>>> CA Lic. 773985 >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> List sponsored by Redwood Alliance >>>> >>>> Pay optional member dues here: http://re-wrenches.org >>>> >>>> List Address: [email protected] >>>> >>>> Change listserver email address & settings: >>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >>>> >>>> There are two list archives for searching. When one doesn't work, try >>>> the other: >>>> https://www.mail-archive.com/[email protected]/ >>>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >>>> >>>> List rules & etiquette: >>>> http://www.re-wrenches.org/etiquette.htm >>>> >>>> Check out or update participant bios: >>>> http://www.members.re-wrenches.org >>>> >>>> -- >> >> William Miller >> Miller Solar.com >> 895-438-5600 >> www.millersolar.com >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> >> List Address: [email protected] >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> There are two list archives for searching. When one doesn't work, try the >> other: >> https://www.mail-archive.com/[email protected]/ >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> http://www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> http://www.members.re-wrenches.org >> >> -- William Miller Miller Solar.com 895-438-5600 www.millersolar.com
_______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: [email protected] Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/[email protected]/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
