I have purchased interlocks for older CH panels and others for around $35 on other sites. If you look around you can get interlocks for all kinds of legacy panels.
Jason On Wed, Mar 27, 2024, 6:47 PM Kirk Herander <kirkh@vermont.solar> wrote: > I agree. That website is way overpriced on their interlocks. I’ve looked > at the one you made from your photos and it looks good. I guess I’ll have > to ask you to make me one someday if I am ever in need!!!! > > *Kirk Herander / **kirkh@vermont.solar <kirkh@vermont.solar>* > > *Owner|Principal, VT Solar, LLC* > > *Celebrating our 33st Anniversary 1991-2024!!* > > dba Vermont Solar Engineering > > 802.559.1225 > > > On Wed, Mar 27, 2024 at 5:33 PM William Miller <will...@millersolar.com> > wrote: > >> Kirk: >> >> >> >> Very interesting. Thank you for that link. >> >> >> >> Let’s consider the options: >> >> >> >> · The interlocks from this supplier can be a bit pricey ($350-450 >> for what we are talking about). >> >> >> >> · If you want to make your own interlock the materials are less >> than $10. The hardest part is cutting clean slots in aluminum plate. I >> use a CNC router. Before I acquired the CNC I made a jig for a standard >> router. Or drill, jig saw and file. The notches are easy to mock up in >> either CAD format (cardboard or computer) and cut with a band or jig saw. >> Your first one will take an hour or two to fabricate. >> >> >> >> · Compare this to a Ronk 7416 at about $1500 (I find the Ronks to >> be a bit wonky to use. Let’s call them Ronky.) Add to that the space >> required and the plumbing and wiring for 400 amps (I think Jason can >> specify a 200 A switch). Plus if you are not combining your inverters in >> an existing load center you need another load center for combining. This >> can really add up. >> >> >> >> With either interlock option, the inverter combining, the interlocked >> bypass and output breakers all fit into one load center. >> >> >> >> I hope the time we spent on this discussion helps someone out there. >> That’s why we do it. >> >> >> >> Wm >> >> >> >> Miller Solar >> >> 17395 Oak Road, Atascadero, CA 93422 >> >> 805-438-5600 >> >> www.millersolar.com >> >> CA Lic. 773985 >> >> >> >> >> >> *From:* Kirk Herander [mailto:kirkh@vermont.solar] >> *Sent:* Wednesday, March 27, 2024 12:38 PM >> *To:* RE-wrenches; will...@millersolar.com >> *Cc:* Jason Szumlanski >> *Subject:* Re: [RE-wrenches] Sol-Ark 15K AC Output >> >> >> >> www.interlockkit.com - they stock and custom make interlock bypasses >> including multiple breakers. >> >> >> >> Square D also makes a 400 A panel which excepts either bolt on or snap on >> QO breakers. >> >> >> >> >> >> >> >> >> >> >> *Kirk Herander / **kirkh@vermont.solar <kirkh@vermont.solar>* >> >> *Owner|Principal, VT Solar, LLC* >> >> *Celebrating our 33st Anniversary 1991-2024!!* >> >> dba Vermont Solar Engineering >> >> 802.559.1225 >> >> >> >> >> >> On Wed, Mar 27, 2024 at 3:15 PM William Miller via RE-wrenches < >> re-wrenches@lists.re-wrenches.org> wrote: >> >> Jason: >> >> >> >> Replies below. >> >> >> >> Miller Solar >> >> 17395 Oak Road, Atascadero, CA 93422 >> >> 805-438-5600 >> >> www.millersolar.com >> >> CA Lic. 773985 >> >> >> >> >> >> *From:* Jason Szumlanski [mailto:ja...@floridasolardesigngroup.com] >> *Sent:* Wednesday, March 27, 2024 3:12 AM >> *To:* will...@millersolar.com >> *Cc:* RE-wrenches >> *Subject:* Re: [RE-wrenches] Sol-Ark 15K AC Output >> >> >> >> William, >> >> >> >> Thanks for the information on grid peak shaving. That is what I thought >> could be done. The description is a misnomer of sorts (like a lot of things >> in Sol-Ark lingo). It's a bit hard to follow and not nearly well >> enough documented, particularly with respect to parallel systems. You >> are welcome. The Sol-Arc manual is not a great manual in any regards. >> >> >> >> I follow what you are saying about using the 80A input breakers. The >> problem I have is that you must set the generator kW to 36,000 in the >> master inverter, not 9,000W in each inverter. The concept of "underrating" >> the input breakers theorizes that each inverter will share the generator >> pass-through equally. I do not know that to be the case. And what happens >> if the three slave inverters have a fault or are turned off? That would >> allow the single master to pass through the full generator supply. >> Obviously this trips the 80A input breaker and protects the conductors, but >> I feel that is a design deficiency when a single inverter is fully capable >> of passing through all 150A. You may be designing for an eventuality >> that will never occur: If the inverters fail then they should be repaired >> or replaced. While awaiting repair the bypass will keep your loads powered >> at full capacity. >> >> >> >> On top of that, I don't think the 80A output breakers are sufficient >> because each inverter can peak shave 50A with inverter power from the >> batteries. Add that to the theorized balanced 37.5A "grid" input, and you >> are at 87.5A of possible throughput. I am not sure why you are >> designing to deliver more than the inverters will produce. The generator >> support function is intended to assist powering loads when the generator is >> undersized. I define that as the generator ampacity being less than that >> of the inverter system. The 36kVA generator is greater in ampacity than 4 >> Sol-Arc 15s. You can turn the generator support function down or off in >> the Sol-Arc. I would recommend it be set to off for this project. (If >> there are to be occasional loads that are greater than the inverters can >> deliver, like a welder or a car charger, with the plan I suggested you have >> a generator-fed panel that can feed those occasional large loads with the >> generator running.) >> >> >> >> But assuming the 80A input/output concept works, other than a panelboard >> with bolt on breakers, what low-cost load center allows you to fasten four >> 80A backfed breakers? If this is available, I could use a recommendation. >> The load centers I am familiar with only have provisions for one fastened >> backfed breaker. I use to specify bolt-on panels for this but I came to >> believe this is overkill. QO breakers are held in place by the panel cover >> that overlaps the breakers. Other breakers are configured so the contact >> points for the breaker bus are recessed. You need to convince your AHJ >> that this satisfies the requirement. Part of the discussion should include >> the point that off-grid systems are specialized and people that do not >> understand them should not be working on them (or judging them-- is what I >> tell inexperienced plan-checkers). >> >> >> >> With respect to the bypass, I would usually use a DPDT switch to >> accomplish this, Even for 400A bypasses, there seems to be a relatively >> cost effective option in the Ronk 7416 (which to date I have not used). I >> get the concept for smaller (<=100A) generators that you could use a >> generator interlock on an off-the-shelf load center. But they typically >> only allow a single backfed 2-pole breaker, whereas something like a Square >> D QO panel with a backfed 150A breaker requires 4 spaces and is >> incompatible with the interlock device. Since bypass is an emergency >> condition, I sometimes limit my bypass to 100 amps. If you want full >> bypass ampacity you can build an interlock to accommodate any size >> breaker. Here >> <https://millersolar.com/MillerSolar/Portfolio/Commercial/RM/Interlock.JPG> >> is a photo of a large frame breaker being interlocked. Here >> <https://millersolar.com/MillerSolar/Portfolio/Commercial/RM/RM_Interlock.pdf> >> is a design sketch exploring multiple interlock options. >> >> >> >> Always, this is a great discussion and specific recommended equipment is >> appreciated. >> >> >> Jason Szumlanski >> >> Principal Solar Designer | Florida Solar Design Group >> NABCEP Certified Solar Professional (PVIP) >> Florida State Certified Solar Contractor CVC56956 >> >> Florida Certified Electrical Contractor EC13013208 >> >> >> >> >> >> On Wed, Mar 27, 2024 at 12:33 AM William Miller <will...@millersolar.com> >> wrote: >> >> Jason: >> >> >> >> Sol-Arc does provide generator support. They call it “grid peak load >> shaving” and it is described on page 22 of the manual. Below is an excerpt. >> >> >> >> *Error! Filename not specified.* >> >> >> >> For those that may not be familiar with the concept of generator support, >> here is how I describe it: The inverter(s) are programmed for the >> generator capacity. If the generator is powering loads and the demand >> exceeds that programmed generator capacity, the inverter can start >> inverting and synchronize output to the generator to add power. This is >> only possible if battery charge levels are adequate. In the Sol-Arc this >> function can be adjusted or turned off. >> >> >> >> Regarding my recommendations on wire sizing: I may have done a poor job >> describing how I see your project best approached. Below is a diagram that >> may do a better job. Power flow is from left to right: >> >> >> >> *Error! Filename not specified.* >> >> >> >> If you follow what I am laying down, you can see there is no single >> inverter or inverter wire that can pass or create more than 80 amps. Ergo >> #4 copper. The money and time you save can easily purchase 8 80 amp >> breakers. If you look at Diagram 10 in the April 5, 2022 Sol-Arc manual >> you will see this concept shown, albeit without bypass capabilities and >> with a separate “LOAD AC Combiner panel.” The separate panel is >> redundant,-- all of the breakers in the AC combiner panel could be located >> in the “Main Breaker Panel.” >> >> >> >> Contemplate this: Just because an inverter can pass-through 200 amps, >> does not mean it can pass through amps above what the input breaker >> provides. >> >> >> >> I hope I have been more clear. I also hope you don’t spend a lot of >> money on and wrassle wire larger than is needed. >> >> >> >> Call me if I can help in any way. >> >> >> >> William >> >> >> >> PS: Below is a diagram on how to provide bypass. I tried to depict the >> bypass interlock graphically. The point is you cannot turn *on* the >> bypass breaker without turning *off* the inverter output breakers. See >> photos of the actual hardware on the web page linked below. I find bypass >> very handy because if there is an inverter or battery failure the client >> can restore power immediately and I can respond at a more convenient time. >> >> >> >> >> >> *Error! Filename not specified.* >> >> >> >> >> >> Wm >> >> >> >> Miller Solar >> >> 17395 Oak Road, Atascadero, CA 93422 >> >> 805-438-5600 >> >> www.millersolar.com >> <https://mailtrack.io/l/3deb3f7f51095bae3cfd8b42df221b4dca044e0a?url=http%3A%2F%2Fwww.millersolar.com%2F&u=1613865&signature=79e9e2e0e8d662d0> >> >> CA Lic. 773985 >> >> >> >> >> >> *From:* Jason Szumlanski [mailto:ja...@floridasolardesigngroup.com] >> *Sent:* Tuesday, March 26, 2024 6:41 PM >> *To:* William Miller; RE-wrenches >> *Subject:* Re: [RE-wrenches] Sol-Ark 15K AC Output >> >> >> >> #4 wire as the output of each inverter is definitely not adequate, as >> each inverter can pass through 150A of generator power. In theory it would >> be spit across all four, but that doesn't matter. It's an open spigot, so >> at a minimum the output conductors would need to be 150A rated in my >> opinion. The complication arises when you don't know whether the inverter >> can supplement this AC output all the way to the 200A load OCPD integral to >> the inverter. For that reason, I believe you need to size the output >> conductors to 200A, not 150A in this case. I am trying to find out >> definitively if generator support mode is supplied by Sol-Ark s. >> >> >> >> As for paralleling the outputs, landing the outputs on breakers becomes >> problematic and very expensive. Since the outputs need to be 150A minimum >> or 200A maximum (as discussed previously), how would you do a 400A >> panelboard with four of these large breakers in it, keeping in mind that >> all four need to be fastened as backfed main breakers? I don't see a >> practical way to make that happen. >> >> >> >> The same thing applies to combining the generator inputs. You would need >> 4 x 150A backfed breakers, all fastened to the bus. Is there a cost >> effective way to accomplish this? >> >> >> >> Serviceability and bypass are obvious desires, but at what cost? If an >> inverter needs to be taken out of service, it's fairly easy to remove the >> supply and load conductors. And this highlights my issue... What if three >> of four inverters need to be removed from service? Then absolute 150A >> generator power can flow through the remaining single inverter, meaning the >> output conductors need to be sized accordingly. >> >> >> >> Jason >> >> >> >> >> >> On Tue, Mar 26, 2024, 9:15 PM William Miller via RE-wrenches < >> re-wrenches@lists.re-wrenches.org> wrote: >> >> Jason: >> >> >> >> I am wondering on the advisability of hardwiring the outputs of all four >> inverters together. If one inverter fails the other three can backfeed >> into it without any means to disconnect the failed inverter and without >> over-current protection. Have you considered landing the output of each >> inverter on a separate, appropriately sized 2 pole breaker in the output >> load-center? >> >> >> >> In the same vein, how are you feeding generator input into the >> inverters? Are these hard-wired paralleled as well? You might consider >> having the generator feed a dedicated load-center with an appropriately >> sized breaker to feed each inverter. You protect the conductors as >> required and you can isolate any inverter for service >> >> >> >> What size should these breaker be? If your inverter can supply 62.5 AAC, >> upsizing for continuous duty and to the next higher standard breaker size >> you get 80 amps. If you use 80 amp breakers into and out of each Sol-Arc >> you require #4 copper at 75°C. Each inverter and all of the conductors are >> protected for the max current they will see and you get the combined >> amperage at your output. There should be no need to run 400 amp wire. >> >> >> >> BTW, you can easily contrive a bypass system by creating a sliding >> mechanical interlock. You run an appropriately sized feeder between the >> generator fed and inverter fed panels. The bypass breaker in the >> inverter-fed panels is interlocked with the inverter output breakers. The >> installation might look like this >> <https://mailtrack.io/l/e90ccdb6d87171ee02747bc52f4aa4c7f57064ca?url=https%3A%2F%2Fmillersolar.com%2FMillerSolar%2FPortfolio%2FInverters%2Fbattery_iinverters%2FChimney_Rock%2FChimney_rock.html&u=1613865&signature=38c4488f52bdc385>. >> This is way cheaper and easier than installing an additional 200A, >> double-throw safety switch. (A home-made interlock may not be listed but >> what is the worse that will happen if all breakers are on? The inverters >> will detect backfeed and shut down. No harm will come of it.) >> >> >> >> Hope this helps. >> >> >> >> William >> >> >> >> Miller Solar >> >> 17395 Oak Road, Atascadero, CA 93422 >> >> 805-438-5600 >> >> www.millersolar.com >> <https://mailtrack.io/l/7e13e4b3b56e5496552a9f21904f404635490f63?url=http%3A%2F%2Fwww.millersolar.com%2F&u=1613865&signature=6c634bcc39faeca3> >> >> CA Lic. 773985 >> >> >> >> >> >> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On >> Behalf Of *Jason Szumlanski via RE-wrenches >> *Sent:* Tuesday, March 26, 2024 2:26 PM >> *To:* RE-wrenches >> *Cc:* Jason Szumlanski >> *Subject:* [RE-wrenches] Sol-Ark 15K AC Output >> >> >> >> I am going to have a quad-stack of Sol-Ark 15K for an off-grid 120/240V >> system with a 150A generator. I know the max real power is 62.5A each >> inverter including battery and PV. That would be 62.5A x 4 = 250A total. I >> intend to connect the output of the 4 inverters together with a 5-port >> Polaris tap, with the output of the Polaris Tap going to a 400A main lug >> only panelboard. >> >> >> >> My question revolves around the 200A passthrough capability for the >> generator, which is 150A max output and would be connected to the Grid >> input on each inverter. Since each inverter would need to handle the full >> pass-through current, that would require minimum 150A conductors on the >> input side of each inverter. I am under the impression that the inverters >> can supplement the "grid" or generator in this case if the current exceeds >> the available input. That means the inverter would have 150A of input plus >> 62.5A of inverter power for a total of 212.5A. But there is a 200A load >> OCPD, so I could size the load conductors from each inverter for 200A. >> >> >> >> Obviously the 4 inverters can only pass through 150A from the generator >> in total, which would probably be split among them, but could go through a >> single unit if the rest fail. >> >> >> >> Now, is it possible for each inverter to output 62.5A each PLUS 150A of >> generator power spread across them for a total of 400A? That is important >> because I would need to size the combined output conductors for 400A if >> that is the case. >> >> >> >> I guess I'm not clear on how Sol-Ark 15K handles grid/generator >> assist/supplement. It does not seem to be documented clearly. >> >> >> >> Jason Szumlanski >> >> Florida Solar Design Group >> >> >> >> >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> <https://mailtrack.io/l/5f5ecb45fa0ccb0d11cccafb2c0f97618fa79e70?url=http%3A%2F%2Fre-wrenches.org&u=1613865&signature=fdeabe6cf92ab25a> >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> <https://mailtrack.io/l/020c93287659704ad1c52093f304e341f5d0498c?url=http%3A%2F%2Flists.re-wrenches.org%2Foptions.cgi%2Fre-wrenches-re-wrenches.org&u=1613865&signature=3efe2a50c80c33a7> >> >> There are two list archives for searching. 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_______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org 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/re-wrenches@lists.re-wrenches.org/ 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