<div dir="auto">FYI Sol Ark sales engineer has suggested the following:</div><div dir="auto"><br></div><div dir="auto"><div><div style="font-style:normal;font-weight:400;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:1px;text-decoration:none;font-family:aptos,aptos_embeddedfont,aptos_msfontservice,calibri,helvetica,sans-serif;font-size:0.916667rem;color:rgb(0,0,0)" dir="auto">“For the 15K, we've recommended <a href="https://shop.accuenergy.com/product/acuct-4146r-800a-100ma/" style="font-size:0.916667rem;font-family:aptos,aptos_embeddedfont,aptos_msfontservice,calibri,helvetica,sans-serif;color:rgb(66,133,244)">AcuCT R Series - AcuCT-4161R-800:100mA | Accuenergy</a> with 100mA output. </div><div style="font-style:normal;font-weight:400;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:1px;text-decoration:none;font-family:aptos,aptos_embeddedfont,aptos_msfontservice,calibri,helvetica,sans-serif;font-size:11pt;color:rgb(0,0,0)"><br></div><div style="font-style:normal;font-weight:400;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:1px;text-decoration:none;font-family:aptos,aptos_embeddedfont,aptos_msfontservice,calibri,helvetica,sans-serif;font-size:0.916667rem;color:rgb(0,0,0)" dir="auto">On the inverter, you will need to adjust the CT ratio to 8000:1. Also note that this will have to be confirmed with Tech Support upon installation/commissioning, to prevent void of warranty.”</div></div><br></div><div dir="auto">The CT has an ID of 4” so all parallel conductors should pass through just fine. </div><div dir="auto"><br></div><div dir="auto">The 30 and 60K units use a similar Accuenergy CT but higher amp draw that are not compatible with residential units. </div><div dir="auto"><br></div><div dir="auto"><br></div><div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jul 18, 2024 at 11:51 AM Dan Lepinski, P.E. <<a href="mailto:Dan@ntree.org">Dan@ntree.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204,204,204)">Chris,<br>
<br>
If the only goal is to avoid backfeeding the grid, in the configuration as described, the inverter will sense any outbound current and reduce its output accordingly.<br>
<br>
Should you desire to monitor incoming power and energy, all readings will need to be multiplied by three .. which unless there's a specific setting in the inverter to automatically allow this scaling (unlikely, and requires Sol-Ark verification), such multiplications will need to be consciously performed when looking at the data.<br>
<br>
Not ideal from a data tracking perspective, but it will at least meet the zero-backfeed stipulation. (You may want to discuss adding bi-directional CT "current scaling" capability with Sol-Ark if it doesn't already exist in their firmware.)<br>
<br>
<br>
Dan<br>
<br>
<br>
<br>
On 7/18/24 10:24, Chris Sparadeo wrote:<br>
> Hi Dan,<br>
> <br>
> Thanks for your thoughts. The idea of 1/3 CT crossed my mind as well. The question is how to set up the inverter with a 3x multiplier on those two CTs to get a full 800A reading. I assume that would be something a Sol Ark engineer would have to program remotely? <br>
> <br>
> Thanks again,<br>
> <br>
> -Chris <br>
> <br>
> On Thu, Jul 18, 2024 at 8:42 AM Dan Lepinski, P.E. <<a href="mailto:Dan@ntree.org" target="_blank">Dan@ntree.org</a> <mailto:<a href="mailto:Dan@ntree.org" target="_blank">Dan@ntree.org</a>>> wrote:<br>
> <br>
> Gentlemen,<br>
> <br>
> A possible solution is to utilize one CT around one each of the three paralleled 400 MCM. One CT around one of the three L1 conductors, and the other CT around one of the three L2 conductors. Ensure correct direction for current flow when you install them. (Sol-Ark calls it "polarity".)<br>
> <br>
> With three 400 MCM in parallel, each conductor will carry nominally 1/3 of the total current, regardless of direction (in or out). Thus a CT around each of the three phase conductors will measure 1/3 of the total current.<br>
> <br>
> 800 Amps / 3 = 266.67 amps.<br>
> <br>
> As you probably know, there's a 200 amp CT and 600 amp CT on Sol-ark's website. <a href="https://shop.sol-ark.com/catalog/extra-large-cts/" rel="noreferrer" target="_blank">https://shop.sol-ark.com/catalog/extra-large-cts/</a> <<a href="https://shop.sol-ark.com/catalog/extra-large-cts/" rel="noreferrer" target="_blank">https://shop.sol-ark.com/catalog/extra-large-cts/</a>><br>
> <br>
> Obviously the 200 amp CT isn't suitable (267A > 200A), which leaves the 600 amp part.<br>
> <br>
> Program the inverter accordingly, with an understanding the 600 A CT will be reading 1/3 of the total current.<br>
> <br>
> You'll give up some resolution (267A/600A = 44.4% of the total full-scale current reading for a 600 amp CT), but with proper inverter setup, it will work for purposes of limiting export.<br>
> <br>
> That said .. each CT requires its own burden resistor, and the inverter isn't designed for three to be connected as you're discussing, whether series or parallel.<br>
> <br>
> <br>
> Hope this helps...<br>
> <br>
> <br>
> Dan<br>
> <br>
> <br>
> -- <br>
> Dan Lepinski, P.E.<br>
> Professional Solar Consultant & Electrical Design Engineer<br>
> Serving the Solar Industry Since 1972<br>
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> <br>
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> Unless indicated otherwise, all information contained in this message is privileged and confidential. As such, it is intended only for use by the addressee(s) named above, and others who have been specifically authorized to receive it. Correspondence designated as privileged and confidential is subject to all terms and conditions of any Confidentiality Agreements and/or Non-Disclosure Agreements in effect between our respective parties.<br>
> <br>
> <br>
> <br>
> <br>
> ><br>
> <br>
> > On Thursday, July 18, 2024 at 07:04:47 AM CDT, Kirk Herander via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a> <mailto:<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>>> wrote:<br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> > As an aside, I ran into this with a Fortress True 12kw. (As of several months ago) They have not tested parallel CTs, nor have they tested single CTs in any service above 200A. They would not approve my plan to parallel CTs on a parallel conductor, 400A service. <br>
> <br>
> ><br>
> <br>
> > Fortress does have an input for a 3rd party meter, who knows if it's been developed, maybe Sol-Ark does too.<br>
> <br>
> ><br>
> <br>
> > Definitely run it past Sol-Ark first.<br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> > On Thu, Jul 18, 2024 at 7:46 AM Jason Szumlanski via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a> <mailto:<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>>> wrote:<br>
> <br>
> > You should be able to parallel 6 CTs (3 per phase) as long as you get the phases and directions right. The question really comes down to whether the Sol-Ark can handle the current from 800A at the CT ratio (which I believe is 2000:1). For practical purposes, on an 800A service, particularly residential, you will probably never see more than 600A, so it would probably be fine.<br>
> <br>
> ><br>
> <br>
> > But I would like to know what Sol-Ark says about this. It does not appear to be documented. For the 30K and 60K they have recommended CTs for up to 1200A. I'm not sure if 600A measurement is a hard limit for the 15K considering that's the largest single CT they specify in their documentation. <br>
> <br>
> ><br>
> <br>
> > Jason<br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> > On Thu, Jul 18, 2024, 7:23 AM Chris Sparadeo <<a href="mailto:sparadeo.chris@gmail.com" target="_blank">sparadeo.chris@gmail.com</a> <mailto:<a href="mailto:sparadeo.chris@gmail.com" target="_blank">sparadeo.chris@gmail.com</a>>> wrote:<br>
> <br>
> > Hi Jason,<br>
> <br>
> ><br>
> <br>
> > Sorry for not clarifying. This is a export limited scenario, so CTs would still be required. <br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> > On Thu, Jul 18, 2024 at 6:51 AM Jason Szumlanski <<a href="mailto:jason@floridasolardesigngroup.com" target="_blank">jason@floridasolardesigngroup.com</a> <mailto:<a href="mailto:jason@floridasolardesigngroup.com" target="_blank">jason@floridasolardesigngroup.com</a>>> wrote:<br>
> <br>
> > This may or may not be helpful, but are you sure you need the CTs? They are not always required. You would need them for power export limiting or grid peak shaving, but for straight grid-tied with or without battery backup, you don't need them. <br>
> <br>
> ><br>
> <br>
> > Jason Szumlanski <br>
> <br>
> > Florida Solar Design Group <br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> ><br>
> <br>
> > On Wed, Jul 17, 2024, 8:41 PM Chris Sparadeo via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a> <mailto:<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>>> wrote:<br>
> <br>
> > Hey there wrenchers,<br>
> <br>
> ><br>
> <br>
> > I am working on a larger project with 6 Sol-Ark 15K units and an 800A service. The main service conductors are 3 parallel runs of 400 kcmil. I am wondering how to CT these conductors from the master inverter. Sol Ark tech support has not been very helpful so far. I have the included 300A CTs ....and I do know that they make a 600A CT, but its physical size and rating aren't a good fit. Does anyone have experience with either a Sol Ark or third party CT that might fit this 800A configuration? <br>
> <br>
> ><br>
> <br>
> > Kindly,<br>
> <br>
> ><br>
> <br>
> > Chris Sparadeo <br>
> <br>
</blockquote></div></div>