Re: [RE-wrenches] #10 THWN-2

Marco, I found the same situation as what David mentions -- when we were doing a high profile job that was going to be inspected by a certain someone from Las Cruces, all the wire available from local suppliers was only physically marked as THHN / THWN, but when we dug a little deeper and found th

Re: [RE-wrenches] Encore Wire #10 THWN-2

Hi Marco, I'd second Dave's recommendation regarding Encore Wire. We've been using #10 and #12 THWN-2 made by Encore for a few months. When I called Encore, they were helpful finding an electrical supply house that carries it here in Tucson. The wire is indeed rated THHN/THWN/THWN-2, so it s

Re: [RE-wrenches] #10 THWN-2

THWN-2 smaller than #8 is hard to find but I hear http://www.encorewire.com/site_flash/index.html makes it and that Graybar sells it. When I asked Southwire about it about two years ago, I got a collective "huh?" Original Message Subject: Re: [RE-wrenches] #10 THWN-2 From: Da

Re: [RE-wrenches] #10 THWN-2

Marco, The #10 THWN wire that your local suppliers carry may be cross-listed as THWN-2. My understanding is that it is not uncommon for smaller gauge wire to carry more listings than are printed on its insulation. (If that¹s not true, we¹ll find out shortly from someone on the list.) If your local

Re: [RE-wrenches] RETURN AMP SETTING

I am talking with a customer who wants to do a standalone system using an Endurance wind machine, solar, and genset.   I have no experience with Endurance other than to know it is a good machine.  Talking with Magnum today they informed me that the MS 4XXX PAE inverter, combined with the ARC rem

Re: [RE-wrenches] calculating DC voltage drop

Dana, 2.6% voltage drop also means 2.6% power loss.  To go from 2.6% loss to 1.6% loss you gain about 4.1 watts for the extra $22.  That is $5.36/watt so it probably makes sense to use the larger wire.  Now compare 1.6% and 0.4%: you gain about 4.9 watts for the extra $140, that's $28.57/watt.

Re: [RE-wrenches] aluminum heat fins for radiant retrofit...who's got 'em?

I have used this approach with 1/2 inch nom. copper tube, it works.  The Aluminum I got form New Jersey Aluminum, they sold out to another company.  I am not sure it is made any more, but I had a custom extrusion made for me for about $3000  I have also seen a thin folded AL fin from floor heat

[RE-wrenches] #10 THWN-2

Finding that wire in these here parts is pretty much impossible. Can any of my CA. brethren/sistren provide me any leads on wholesalers in either northern or southern CA. that carry #10 THWN-2 wire? Thanks, marco ___ List sponsored by Home Po

Re: [RE-wrenches] calculating DC voltage drop

All, This is all very interesting, but on the dc side, it is primarily an issue of energy loss for large grid-connected systems. My rule is 2% voltage drop for dc side and 1% for ac side. When we talk about dc % voltage drop, most of what has been discussed in this thread is instantaneous

[RE-wrenches] calculating DC voltage drop

Ray, The $ could be making power I agree on a large scale project. The point here is where is the cutoff point? Let’s take a very small cabin system: 410 watts or 13 amps [inc.1.25%]@ 44VOC, over a 90’ one-way run. Utilizing and Electro-calc with 2008 NEC installed 2.6%VD – 1.

Re: [RE-wrenches] RETURN AMP SETTING

Hi gang. Just a quick note. It has awhile since Christopher was with Outback. Steve Higgins is the Outback manufacturer representative on the list. Dana wrote at 08:36 AM 7/22/2010: >Chris Freitas of Outback can you chime in here? > >Thanks, Dana Orzel __

Re: [RE-wrenches] calculating DC voltage drop

Mike, I would respectfully challenge both reasons ;^)} . The responses already posted today cover them: you don't need to compensate for intermittent high-insolation conditions when sizing for voltage loss, as this is not a Code issue; Code addresses ampacity and OCP

Re: [RE-wrenches] Imbalance In Multiple String Charging Current

Mark, If you had one "healthy" string connected in parallel with two "weak" strings, the tendency would be for the weaker strings to pull the stronger string down to their level.  It's more likely an impedance issue in the string with the lower current.  All other things being equal, look for b

Re: [RE-wrenches] calculating DC voltage drop

Allan, I use Imp*1.25 because NEC calls out a 125% adder for unexpected high-insolation conditions (snowscapes, cloud effect, yellow houses next door, etc). And because I am an engineer and like to be conservative :). -Mike --- Michael Kelly Applications Engineer NABCEP Certified Solar

Re: [RE-wrenches] calculating DC voltage drop

Hi Dana; I'd say that's a bit overkill for today's market. That money could be making more power, not just preventing losses. Definitely a law of diminishing returns on wire sizing. If you allocated 50% of the budget to wire, and 50% to PV, your losses would be very low, (immeasurable but unfo

Re: [RE-wrenches] calculating DC voltage drop

Mike, Why do you make this exception, please? Allan Sindelar Allan@positiveenergysolar.com NABCEP Certified Photovoltaic Installer EE98J Journeyman Electrician P

Re: [RE-wrenches] Imbalance In Multiple String Charging Current

OK, So no takers for the low current string being in a healthier, higher state of charge! Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 www.berkeleysolar.com ___ L

Re: [RE-wrenches] line-side tap in subpanel

It would depend on which side of the OCD the 380 amp rated cable was on. IF the 400 A OCD is integral to the panel, then it doesn't matter what the cable size is on the other side of the OCD, it's protected by the OCD, and the current can't exceed that. If the OCD is remote and the subpanel does

[RE-wrenches] calculating DC voltage drop

For array to power center or Inverter; I use 125% of amps @ max power and run the wire calculations at 1% VD. We have set Fluke meters on clamped on @ both ends and talked with radios & compared the readings. We have not seen any noticeable VD down to .00vdc. Perhaps overkill? Thanks,

Re: [RE-wrenches] calculating DC voltage drop

Marco and I were just discussing this as well. For long term energy loss purposes, you really would want to use annual average voltage and current for the array. (let's see that on a module spec sheet ☺) Basically, it would really depend on the installation and location. I could see for a hot r

[RE-wrenches] line-side tap in subpanel

Greetings all, When the subpanel is fed with 380A wire and the OCD is 400A and the panel bus is 400A, which number would be used for determining 120% capacity? I'm thinking the 400A because the bus would be overfed before the wire? So if we want to land 225A of OCD for solar output on the line t

Re: [RE-wrenches] calculating DC voltage drop

Hi All, I agree with Ray with the exception that I use Imp*1.25 in my calculations. I developed a simple spreadsheet for either fixed conductor size or for fixed voltage drop. You can feel free to use it by downloading here: http://www.mechanicalmike.com/solar/DC_Voltage_Drop_Calculations_Temp

Re: [RE-wrenches] calculating DC voltage drop

I use actual operating current, without multipliers. I also use actual temperatures, not the worst case temperatures that many use. I created a spread sheet that uses the NEC adjustments for wire temperature, (see NEC chapter 9, table 8, FPN 2) It makes quite a difference! Volt drop and the accom

[RE-wrenches] Fw: Preventing Worker Deaths in the Solar Energy Industry

- Original Message - From: face (CDPH-OHB) To: undisclosed-recipients: Sent: Thursday, July 22, 2010 10:36 AM Subject: Preventing Worker Deaths in the Solar Energy Industry California FACE Program Investigates the Deaths of Three Solar Installers The California Fatality Assessme

[RE-wrenches] Imbalance In Multiple String Charging Current

What do specific gravity and load, rest and charge VPC tests say? The VPC tests will usually pinpoint a weak cell. Higher VPC reading under a high state of charge and lower VPC under a big load, normally done with the array & generator turned off to maximize the effect. Typically the sp

Re: [RE-wrenches] calculating DC voltage drop

Most appropriate is Ip-max. If you are "operating" @ ISC or above, your voltage has already dropped to zero... AKA 100% voltage drop. Pray for Sun! Matt Lafferty -  Sent from my Palm Pre On Jul 22, 2010 12:22 PM, Marco Mangelsdorf wrote: When calculating the voltage

[RE-wrenches] calculating DC voltage drop

When calculating the voltage drop from a PV array to the inverter, what's the most common accepted practice? To use the Isc X 1.25 or 1.56 as the multiplier? Thanks, marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@list

Re: [RE-wrenches] Imbalance In Multiple String Charging Current

try disconnecting all strings from each other... (check all electrolyte levels and Specific Gravity).. let them rest for a while... and compare individual battery voltages... you're looking for about 2 volt differences... (bad cells)... basically you're up against an ohm's law thing... hig

Re: [RE-wrenches] Imbalance In Multiple String Charging Current

Mark, Do the interconnects total the same length in each string?  There could be a bad connection somewhere in that string.  But more than likely this behavior is the result of a cell (or cells) that has a high impedance because it is sulfated.  How do the specific gravity numbers look. Kent

[RE-wrenches] Imbalance In Multiple String Charging Current

Folks, I have three strings of batteries cabled in parallel to a common buss bar. During charging, one string takes significantly less current than the others. What can I infer from this? Is the low current string healthier, presenting higher impedance due to a higher state of charge? Or is ther

[RE-wrenches] RETURN AMP SETTING

Chris Freitas of Outback can you chime in here? Thanks, Dana Orzel Great Solar Works, Inc E - d...@solarwork.com V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 web - www.solarwork.com Responsible Technologies for Responsible People since 1988" From: re-wrenches-boun...@lists.

Re: [RE-wrenches] Propane Generator, Dual Outback Inverters

Darryl: There is a scenario in which problems occur: If your loads exceed the generator capacity, the Outback system will fail. The Xantrex inverters are superior in this scenario in that they will transition to invert mode to synchronize with the generator and support the generator as long

Re: [RE-wrenches] Propane Generator, Dual Outback Inverters

I should have been a bit more clear about my application. I'm not worried about battery charging rates or load percentage on the generator. I've already determined that this size generator will normally run at a good efficiency level. I am more concerned with the quality, longevity, and enclosure.

[RE-wrenches] aluminum heat fins for radiant retrofit...who's got 'em?

Hello, Wrenches~ Please see the photo on page 48 of the latest *Home Power* magazine (#138). This shows aluminum fins with an extruded clip into which Rehau type radiant floor tubing can be clipped. Where can I get these parts for resale? Have any of you observed an installation where this appro

Re: [RE-wrenches] RETURN AMP SETTING

boB Time for you to design an RTS that also measures SG. Then my Classic can: Set Return Amps automatically. Alert for an excursion in charge time Alert for low water Etc. Thank you, Maverick Maverick Brown BSEET, NABCEP Certified Solar PV Installer ® President & CEO Maverick Solar Enterpri