88 T-Bird 3.8-- Charging system issue. Reply #15 – December 12, 2011, 01:02:14 PM Most Quote Selected
88 T-Bird 3.8-- Charging system issue. Reply #17 – December 14, 2011, 02:42:17 AM wow! seriously!, thats the thickest #10 I have ever seen.with that being approx 3/4'' wire loom, it its amazing its insulation makes it appear to be along the lines of a #4 or #6 at best.Based on your thoughts on the max amps typically expected out of the alternator, I totally agree as we don't typically expect to see 100% loads. Thats what i suspected earlier when i was trying figure out what ford was thinking with the #8. This coupled with time and corrosion likely does have a negative effect on our cars main headlamp switch.If DC power requires much less copper than AC, then the entire world would have stayed on the path of DC power plants today as was the case in Chicago during the battle of the AC vs DC war. ,, copper is expensive. If we had stayed DC your service drop to your house would be along the lines of 4/0 or 250KCMIL single phase excluding voltage drop.AC exampleA 100A source breaker engineered for 80% as allowed by the NEC at a reasonable 150' one way distance would require #4awg if installed in conduit at 75decC.DC examplein dc the total loop footage must be determined and integrated into the engineered circuit.A 100A source breaker engineered for 80% as allowed by the NEC at a reasonable 150' distance (300' loop) would require 2) 500mcm per polarity or 4 conductors total.11.1 K factor constant for copper in DC power x 300' loop x 80A / .25v drop = 1,065,600cmil of copper which converts to 2) 500mcm cables per polarity which can be "considered" close enough.The same 100A circuit in dc power but at 65loop feet would only require 1) 250mcm per polarity but a 4/0 could be "swagged".The same 100A circuit in dc power but at 100' loop feet would only require approx 1) 350mcm per polarity.**as a note: when 25' one way is the distance, this is the point at which distance no longer has a huge effect on DC circuits and the wire size for both AC and DC become aligned almost perfectly,, as in all you have to do is refer to the NEC table 310.16 and just select your desired amperage and the wire size is given to you.In all cases ~ normally~ the distance effects on AC is "not normally" a consideration except in unique situations or very excessive length designs. IF an AC circuit were 300', id be pocking at the math to bring the voltage drop into the consideration list or at best just jump up one size.You said it yourself in post 11 but reversed your engineering in post 16 which i think you may have just fat fingered a key or two.At the end of the day, DC power is more reliable and has much much less external environmental influences than AC. In the end, the expense of the precious mineral copper is what sold the world on AC power grids of today, otherwise copper prices would likely exceed or meet gold , or.......Aluminum would be the standard or some galvanic version of it.Hell, in Iraq, those folks use brass coated steel conductors on their half assed power systems,, 220v on thier hot leg for single phase services.On a positive note, literally, if cars went back to a -power source, no one today would have to deal with corrosion all that much,,lol. Quote Selected
88 T-Bird 3.8-- Charging system issue. Reply #18 – December 14, 2011, 07:54:53 PM J the Quote Selected
88 T-Bird 3.8-- Charging system issue. Reply #20 – December 16, 2011, 07:28:32 PM If you to see a live solar system on line right now, click on this link from my fat spanial, this is one of my first systems we did for pen 15s.http://view2.fatspaniel.net/PV2Web/merge?&view=PV/standard/Simple&eid=220809ummm,, 4 stages above 14awg is #8. Nec does not honer the odd numbered wires except 1/0 and 3/0.now ask the solar guys how much current carrying capacity does 8awg have if it is conduit : )The solar industry is really wrecking the electrical industry with Chinese math to electrically explain off their installations to keep costs down.Besides, solar guys are really all that concerned with distance and voltage drop because they dont deal with it.They combine series parallel chunks of solar panels with the electrical objective to meet the mid range input voltage of an inverter system, as in 190vDC to 280vDC for a single phase system. the lower the voltage, the more concern you have with drop. I keep agreeing with you on everything you say except my observation that I think ford derated too far with the 8awg. you have to wonder why over the past 6 or so years new alternators for these cars are coming with a replacement connector kit,, they are burning up for a reason, adn the headlamp switch assembly plastic connector isnt getting all brown looking due to heat for nothing.The car is plainly saying it needs bigger wire in just about every situation i can think of.I was just trying to have a conversation about the problem, not to derate you because im not going to do that. What i do say though is that if you do wire 8awg to a 70a circuit , in all cases per the NEC, it must not be housed inside of a raceway or jacket and it can not be anything but "free air".Compare / google NEC Table 310.16 and table 310.17the type of wire used with respect to stranded vs flex is a consideration as well as jacket insulation.its my observation that the OEM stranded wire is obviously rated for less ampacity than the 8awg flex but you have to dig hard to get that data. Cop-Flex by cobra wire has charts which are the best reference for this info.,, the NEC has yet to catch up with this yet even though cobra wire has been around for ever.I take it your not the type of person to be in possession of bad information and you would make darn sure you spoke correctly about something,, thats what i was sharing but we can agree to disagree on the idea of how much current 8awg can carry "based on its engineered design". again, if its installed inside a jacket or pipe or some form of conduit then it is subject to table 310.16 within that table, you must look on the wire and find its "rated" and "designed" temperature range.If its not listed then you have to ,, and must! observe the lesser ampacity.Again, i already pointed out that ford "could have" derated the wire as to cover only about 40 to 45 amps and they would be compliant to the NEC in this fashion.The honest discussion was when you said you can use 8awg up to the amperage you pointed out,, there is no instance that is possible or logical unless the wire is hanging in free air.dont listen to those stupid solar guys,, Alpha Technologies is about the only Tier 1 supplier who engineers solar system correctly, and why?well, lucky for all of us this industry has not really taken off real huge yet but if it would, there would be ***Much MORE*** roof top fires than we have already had.You see, the solar guys are still learnin' and they refuse to understand DC Power like the DC power experts keep trying to educate the the correct applications. It all comes down to cost.Just a couple day ago, so many roof top fires cause a stupid webinar to happen, and yet the end results are going to come down to simple things like getting their head around ohms law and remembering that kw is kw no matter how you dice it and working with batteries,,, (ie- panels are batteries) that they are subject to low and high current situations, more so in the solar industry as that sun moves, the voltage goes down but the current "demand" in the panel goes up until we reach SCCR. Time marches on and they will soon come face to face with what is meant by ~amps interrupt current and the differences between it and sccr.here is the link to their final conclusions of "what they could learn",, its nice to see they decide to do their engineering by using customers as test beds.http://www.webvent.tv/webinar/140Ill bet you dont see this happening on my recent project for solar shade sheltershttp://www.alpha.com/pen 15s-communications-powering-up-ceremony/I was solely responsible for the success they have at pen 15s for the Deer Valley project in AZ. The whole alpha team put together a highly engineered product that is correct but likely will not be cost effective to continue if not for hand outs from the gov't,, as still is the case for the state of NJ.http://www.bizjournals.com/phoenix/print-edition/2011/08/12/pen 15s-conserves-energy-consumption.htmlback to cars,,, and likely backing off hijacking this thread,,lol. Quote Selected
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