---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 01/03/08: 19 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:53 AM - Re: Re: Powering the Ignition and Fuel Injectors on Egg. Subaru (Rodney Dunham, M.D.) 2. 05:54 AM - Re: Compass Requirements in Experimental Aircraft (updated) (MauleDriver) 3. 07:05 AM - Push to Start (Edward Christian) 4. 08:35 AM - Re: Push to Start (Hinde, Frank George (Corvallis)) 5. 08:39 AM - Compass Requirements in Experimental Aircraft (Fergus Kyle) 6. 08:42 AM - Compass Requirements in Experimental Aircraft (Fergus Kyle) 7. 09:11 AM - Re: Re: Powering the Ignition and Fuel Injectors on Egg. Subaru (Terry Watson) 8. 10:06 AM - Re: EXP-Bus, et. als. (Robert L. Nuckolls, III) 9. 10:06 AM - Starter push button?? (Robert L. Nuckolls, III) 10. 11:13 AM - Re: EXP-Bus, SUBARU wiring (Carlos Trigo) 11. 01:17 PM - Re: EXP-Bus, SUBARU wiring (Robert L. Nuckolls, III) 12. 01:35 PM - Re: EXP-Bus, SUBARU wiring (Dj Merrill) 13. 03:06 PM - Re: Engine GND (Frank Stringham) 14. 03:45 PM - Re: Engine GND (Hinde, Frank George (Corvallis)) 15. 06:39 PM - Re: Compass Requirements in Experimental Aircraft (updated) (Jim Baker) 16. 10:20 PM - sizing wire (Lincoln Keill) 17. 10:50 PM - Re: sizing wire (mike humphrey) 18. 10:53 PM - Re: sizing wire (B Tomm) 19. 10:59 PM - switch rating question (B Tomm) ________________________________ Message 1 _____________________________________ Time: 04:53:32 AM PST US From: "Rodney Dunham, M.D." Subject: RE: AeroElectric-List: Re: Powering the Ignition and Fuel Injectors on Egg. Subaru Carlos, Pardon me for butting in here, but... The ExpBus is a "canned" product designed by Greg Richter to be used according to Mr Richter's design principles as outlined in Mr Richter's book, "Wiring for Smart People". I heard Mr Richter speak at OSH in '05 and read his "book". I liked it. Perhaps you should ask Mr Richter to expound on the proper care and feeding of the ExpBus and how it interacts with your engine's systems. That would make sense, wouldn't it? After all, it's his system, isn't it? If you go to the Blue Mountain Avionics site there's a discussion board there and I'm sure Greg will be happy to answer all your questions. Alternatively, if your engine designer, (Mr Eggenfellner ?) recommends this product, perhaps he could explain his choice and how to integrate it into his design principles. It seems to this humble poster that Bob has more than enough to do just teaching us his time tested design philosophies and how to implement them in our OBAM aircraft. Rodney in Tennessee Unabashed Nuckollhead DO NOT ARCHIVE ________________________________ Message 2 _____________________________________ Time: 05:54:06 AM PST US From: MauleDriver Subject: Re: AeroElectric-List: Compass Requirements in Experimental Aircraft (updated) Jim Baker wrote: >> I believe that ATC gives only magnetic heading vectors (though it seems that it's time to go to >> true headings). >> >> I'll second that. My current job is a contract procedures >> development specialist for the FAA and the things we see with >> facility Mag Var issues would make most folks cry. >> >> A lot of the facility Mag Vars go back to the 60s, 70s and 80s. >> Consider what happens when you have an NDB with a 60s Mag >> Var, a nearby VORTAC with a 70s Mag Var, and an ILS with an >> 80s Mag Var. >> >> ZZV ZANESVILLE VOR/DME Variation: 06W (1990) >> TVT TIVERTON VOR/DME Variation: 03W (1965) >> >> Only 32 miles from each other. If you saw how much havoc >> changing just one Mag Var causes, which you really can't do >> efficiently because of the ripple effect....change one, you'd better >> be prepared to change a lot of them. That's why Mag Vars don't >> get changed often. >> >> Personally, I'm hoping for the pole reversal........ >> Accommodating the legacy of past technologies is like having a 2 ton stone around one's neck! Arrrrghhhh! I can't even imagine. On one hand we all want to move ahead as fast as possible, on the other, none of us want any piece of equipment we use to become obsolete. The whole VOR infrastructure is down there but I haven't tuned one in since my last training exercise. And in 7 or 8 years of instrument flight, I've never been asked to intercept a radial (even a hold). They are handy waypoints though. When is the next pole reversal predicted? I guess I'm dead then huh? ________________________________ Message 3 _____________________________________ Time: 07:05:49 AM PST US From: Edward Christian Subject: AeroElectric-List: Push to Start I would like to use a start button on the Z-11 diagram with regular mags but have the option to convert to P-Mags later. Can someone explain how to or point me to a reference. Ed ________________________________ Message 4 _____________________________________ Time: 08:35:25 AM PST US From: "Hinde, Frank George (Corvallis)" Subject: RE: AeroElectric-List: Push to Start Not quite sure what question your asking Ed? The push button is easy it just takes the +12V wire form the start contactor and grounds it when the button is pushed, thus pulls in the contactor. A to wiring the mags I would not put in a key swtich to control both mags...I mean if you do that you have a single point of failure controlling both ignitions. Granted it is unlikely to fail because you have to ground the P leads to shut them off, but even so a separate switch to control each P lead is desirable. The to start you simply turn on both P leads (unground them) and hit the start button. The nice thing about the P mags is they are wired the same way...I.e have a terminal that connects directly to the P lead you will have already installed. The only extra things you will need in moved to a P mag from an existing mag is a +12V supply for each Pmag and a good ground (don't rely on the case). Make sure the +12V lines come from a separate circuit...I.e one fuse for each. If you have two batteries or two alternators, one feed should come from the main bus and the other should come from the essntial bus. Hope that helps Frank -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Edward Christian Sent: Thursday, January 03, 2008 7:02 AM Subject: AeroElectric-List: Push to Start --> I would like to use a start button on the Z-11 diagram with regular mags but have the option to convert to P-Mags later. Can someone explain how to or point me to a reference. Ed ________________________________ Message 5 _____________________________________ Time: 08:39:55 AM PST US From: "Fergus Kyle" Subject: AeroElectric-List: Compass Requirements in Experimental Aircraft Hey, I don't understand why the title is distinct to Experimental aircraft. The compass requirement is the same for any device that moves in a medium if true motion is to be understood. This includes river current, tidal motion and other media. Navigating "by DG" is only valid when the directional gyro is regularly readjusted to the valid magnetic heading* _ (that's why you start out by setting it on the runway for take-off - no need for GPS). There is no need to duplicate the EFIS reading on another display, so it's really only for Heading. It precesses, that's why it needs to be adjusted every ten minutes or so - depending on ground speed. *If you were to fly in the Arctic areas, it might be set to GRID north settings, but that's another story. Taking "Mag var" - may we presume 'magnetic variation'? - from anything but the CURRENT chart for same is tantamount to searching in 1880 for clues to Kennedy's assassin. That's why the rate of change of magnetic variation is published - so one may calculate the present Variation. EFIS changes nothing of import. What is has to do with 'Experimental' beats me. Ferg ________________________________ Message 6 _____________________________________ Time: 08:42:44 AM PST US From: "Fergus Kyle" Subject: AeroElectric-List: Compass Requirements in Experimental Aircraft PS: On this topic, and ATC vectoring, Matt Prather (q.v.) has it down pat - dead on. Ferg ________________________________ Message 7 _____________________________________ Time: 09:11:47 AM PST US From: "Terry Watson" Subject: RE: AeroElectric-List: Re: Powering the Ignition and Fuel Injectors on Egg. Subaru I think you are confusing the ExpBus with Greg Richter's Aircraft Power Board. Check the AeroElectric list archives for Greg's "Aircraft Wiring for Smart People". Terry RV-8A, BMA/EFIS-one, wiring Carlos, Pardon me for butting in here, but... The ExpBus is a "canned" product designed by Greg Richter to be used according to Mr Richter's design principles as outlined in Mr Richter's book, "Wiring for Smart People". I heard Mr Richter speak at OSH in '05 and read his "book". I liked it. ________________________________ Message 8 _____________________________________ Time: 10:06:00 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: RE: EXP-Bus, et. als. At 07:53 AM 1/3/2008 -0500, you wrote: > > >Carlos, > >Pardon me for butting in here, but... > >The ExpBus is a "canned" product designed by Greg Richter to be used >according to Mr Richter's design principles as outlined in Mr Richter's >book, "Wiring for Smart People". I heard Mr Richter speak at OSH in '05 and >read his "book". I liked it. Perhaps you should ask Mr Richter to expound on >the proper care and feeding of the ExpBus and how it interacts with your >engine's systems. That would make sense, wouldn't it? After all, it's his >system, isn't it? If you go to the Blue Mountain Avionics site there's a >discussion board there and I'm sure Greg will be happy to answer all your >questions. Alternatively, if your engine designer, (Mr Eggenfellner ?) >recommends this product, perhaps he could explain his choice and how to >integrate it into his design principles. Greg has his own version of the what-you-see-is-what-you-get electrical system which he proposed in his publication "Aircraft Wiring for Smart People" late in 2004. I attempted to engage Greg in a discussion of the design goals and simple ideas that supported his recommendations but he refused to participate in a friendly critical design review of either his practical advice, science or philosophy of system design. This exchange can be reviewed by interested readers at: http://www.aeroelectric.com/articles/richter/richter.html EXP-Bus pre-dates Gregg's efforts by several years. In 1999 I posted this series of exchanges on the EXP-Bus at: http://www.aeroelectric.com/articles/expbusad.html http://www.aeroelectric.com/articles/expbusthd.html The EXP-Bus was discussed comparatively with Gregg's one-size-fits-all proposal in this discussion about the philosophies and design goals offered in the 'Connection: http://www.aeroelectric.com/articles/What's_the_AeroElectric-List_About.pdf There may be several additional offerings in the wild in addition to the EXP-Bus and Gregg's proposed product. There's a pre-fab assembly popular with the large canard-pusher folks and offered out of Florida as I recall. I don't remember the name of that product. There may be others. >It seems to this humble poster that Bob has more than enough to do just >teaching us his time tested design philosophies and how to implement them in >our OBAM aircraft. There's nothing inherently "bad" about any of these products as long as the laws of physics are observed and as long as consumers of the products are personally satisfied with the utility and performance of their purchase. My objection to such products is that for the same investment of $time$ needed to purchase the product, on can custom assemble a system tailored exactly to the builder's needs and have money left over. Further, one's "home grown" system is crafted from parts wherein the builder knows exactly where to get spares for future repairs and/or expansion. WYSIWYG electrical system products lock you into the choices and sources chosen for you by the designer of that product. It's important that folks understand personal goals for my efforts are driven by a long cultivated professional quest for the elegant solution. Solutions that strive for minimum parts count, low cost of ownership and failure tolerance. These goals are often and easily satisfied without detailed regard as to what parts are used or how much they cost. As soon as one selects a WYSIWYG product, then part of the $time$ expended goes toward the substitution of a third party's ideas and $time$ for that of your own. If it works for you, fine by me. But understand that my reluctance to spend $time$ doing critical design review and/or system integration studies for such products would amount to a tacit recommendation of these products . . . a position I've avoided for reasons cited. Bob . . . ________________________________ Message 9 _____________________________________ Time: 10:06:00 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Starter push button?? Start At 10:01 AM 1/3/2008 -0500, you wrote: I would like to use a start button on the Z-11 diagram with regular mags but have the option to convert to P-Mags later. Can someone explain how to or point me to a reference. Features in the Z-figures can be mixed/matched for builder convenience. Alternative architectures for ignition/starter control are illustrated in Z-13/8, Z-20, Z-21, Z-27, and Z-28. Bob . . . Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 10 ____________________________________ Time: 11:13:26 AM PST US From: "Carlos Trigo" Subject: RE: AeroElectric-List: EXP-Bus, SUBARU wiring Dear Doctor Dunham I really don't have anything against you "butting in here", but if it was to prevent 'lectric Bob from helping ALL AeroElectric listers, regardless of the system they chose to use in their OBAM aircraft, I am happy to see that Bob didn't fulfil your desire. I was not seeking any advice about the ExpBus itself, so there is no need to ask Mr. Richter anything at all. Nor do I need or want to trigger any discussion at all about the advantages or disadvantages of the ExpBus, therefore it doesn't make ANY sense to contact anybody related to the ExpBus. And please don't engage in an ExpBus thread... That's not my intention! Regarding Jan Eggenfellner, who is a nice and decent guy, producing a good alternative engine to our OBAM aircraft (please don't initiate any Lycoming / alternative engines discussion also), he no longer recommends the ExpBus, therefore it doesn't make any sense as well to discuss this issue with him. So, dear Rodney, don't take me wrong. If you have anything against the ExpBus, and/or Mr. Greg Richter (who I didn't know till today was the person behind the ExpBus), please leave that anger out of this, and don't be mad at me or Bob, if he wants to help us, Eggen-Subaru homebuilders with an ExpBus, to reach a better way of wiring our fuel pumps and ignition crucial circuits. No hard feelings Carlos Trigo ________________________________ Message 11 ____________________________________ Time: 01:17:19 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: EXP-Bus, SUBARU wiring At 07:10 PM 1/3/2008 +0000, you wrote: > > >Dear Doctor Dunham > >I really don't have anything against you "butting in here", but if it was to >prevent 'lectric Bob from helping ALL AeroElectric listers, regardless of >the system they chose to use in their OBAM aircraft, I am happy to see that >Bob didn't fulfil your desire. > . . . please leave that anger out of this, and don't be mad at >me or Bob, if he wants to help us, Eggen-Subaru homebuilders with an ExpBus, >to reach a better way of wiring our fuel pumps and ignition crucial >circuits. Carlos, I think you were reading more into Rodney's words than was there. Obviously, there's some miscommunication as to who is promoting which products. Misunderstandings aside, I thought that Eggenfellner had already published suggested system architecture drawings that utilized the EXP-Bus. Did you have any specific questions about Eggenfellner's proposed installation for which I or another List reader can be helpful? Bob . . . ________________________________ Message 12 ____________________________________ Time: 01:35:49 PM PST US Subject: Re: AeroElectric-List: EXP-Bus, SUBARU wiring From: Dj Merrill Robert L. Nuckolls, III wrote: > Misunderstandings > aside, I thought that Eggenfellner had already > published suggested system architecture drawings > that utilized the EXP-Bus. Hi Bob, Eggenfellner is no longer recommending the use of the EXP-bus for their installations. > > Did you have any specific questions about > Eggenfellner's proposed installation for which > I or another List reader can be helpful? > I (and I think a lot of others) are hoping to see a recommended architecture from you that addresses the needs of the Eggenfellner engine package, likely resembling some variant of Z-19 with the rear dual batteries (Z-19/RB I think you called it). Here is a direct link to the current Eggenfellner installation manual, with the electrical section starting on page 45 with their suggested requirements: http://eggenfellneraircraft.com/ESeriesInstallationGuide.pdf Although I am sure the architecture that Eggenfellner has in this document will work, I like your design philosophies and would really like to see what you would recommend for a system, if you have the time to do so at some point. Thanks, -Dj -- Dj Merrill - N1JOV Glastar Sportsman 2+2 Builder #7118 N421DJ http://deej.net/sportsman/ "Many things that are unexplainable happen during the construction of an airplane." --Dave Prizio, 30 Aug 2005 ________________________________ Message 13 ____________________________________ Time: 03:06:42 PM PST US From: Frank Stringham Subject: RE: AeroElectric-List:Engine GND Ok so here is the set up...RV7A.....SD-8 on the Vac pad....FWF Ground block just right of upper center on the firewall. I have a clear run for the engine GND from the port side upper bolt on the SD-8 to the FWF ground block. Is this acceptable and will it produce a good engine GND. Fran @ SGU....RV7A.....finishing up the last zillion items before RV grin T ime ________________________________ Message 14 ____________________________________ Time: 03:45:45 PM PST US From: "Hinde, Frank George (Corvallis)" Subject: RE: AeroElectric-List:Engine GND Hey thats what I did and I made it from Corvallis to St George and back.... :) Yup that will work just fine. Use #2 welding cable for the ultimate in flex ibility. Frank1 RV7a 245 hours ________________________________ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectr ic-list-server@matronics.com] On Behalf Of Frank Stringham Sent: Thursday, January 03, 2008 3:02 PM Subject: RE: AeroElectric-List:Engine GND Ok so here is the set up...RV7A.....SD-8 on the Vac pad....FWF Ground block just right of upper center on the firewall. I have a clear run for the engine GND from the port side upper bolt on the SD-8 to the FWF ground block. Is this acceptable and will it produce a good engine GND. Fran @ SGU....RV7A.....finishing up the last zillion items before RV grin T ime ________________________________ Message 15 ____________________________________ Time: 06:39:19 PM PST US From: "Jim Baker" Subject: Re: AeroElectric-List: Compass Requirements in Experimental Aircraft (updated) X-mailer: Pegasus Mail for Windows (4.41) X-SpamReason %%SpamReason%%: > As long as the pilots aren't changing reference in midstream, > I don't think it's ever a big issue. I hear on the radio all the time > "N12345 fly heading 245" and then later "N12345 turn 10 degrees right." > And even "N12345 say heading." Now, from a previous life as an air traffic controller...tower and radar/RAPCON/GCA...... We almost never knew what your heading was and mostly didn't care unless it was vectors to an ASR approach or, possibly, a PAR, or alternatively, an initial heading to fly on a departure or vectors to final. Usually we just gave you a heading and generally were in the ballpark. Other than that it was all relative motion in relation to the any other aircraft's track. I think the newer ARTS Radar track/tag systems have quick call-up heading and predictive course extension....or perhaps that was just something I'd read from a NASA paper. Anyway, during my time, the only way to know what your heading was is to have asked for it. Jim Baker 580.788.2779 Elmore City, OK ________________________________ Message 16 ____________________________________ Time: 10:20:05 PM PST US From: Lincoln Keill Subject: AeroElectric-List: sizing wire I'm almost through "The Aero-Electric Connection" and haven't been able to find the "Six-Step Guide to Sizing Wire" so could someone back me up on my methodology before I go off and size every wire of my wiring diagram incorrectly? As an example: I will have a 75W landing light in each wingtip controlled with one switch with a wire run length for each light of 15 feet (including the ground wire from each lamp to the spar). Worst case (alternator out with a 12V battery), each lamp will draw 6.25A so initially you'd think 20 AWG wire would suffice (7A max) but since we want to keep the voltage drop below 0.5V we need to use 16 AWG wire (15 foot resistance of .06 ohms times 6.25A is .38V which is less than 0.50V drop). Since my 16 AWG wire can handle 12.5A, I could safely use a 10A fuse for each light and not worry about the wire burning up or a premature trip when first turning on the lights. Alternatively, I could use 14 AWG wire (15A max) and a single 15A fuse for both lights. The switch should be either a 2-2 (16AWG scenario) or a 1-2 (14AWG scenario) rated for 15A. Whew! Have I got all that correct? As B&J once said: "Thanks for Your Support!" Lincoln Keill Sacramento, CA RV-7A P.S. Can anyone recommend one supplier to get all the goodies for a Z-11 system (wire, switches, fuse blocks, starter & battery contactors, fuse links, shunts, silicon diode array, ground bus blocks,crowbar overvoltage protection, low voltage module, etc. etc.)? ________________________________ Message 17 ____________________________________ Time: 10:50:46 PM PST US From: "mike humphrey" Subject: Re: AeroElectric-List: sizing wire B&C, Terminal Town, Steinair, are all excellent suppliers of all the 'goodies" that you will need and tools. Aircraftspruce, Autozone, NAPA, Advance, and EBay, should not be counted out. You know the old saying, 'shop till you drop before you drop the bucks'. Got 1000ft roll of new 22awg unshielded on Ebay for $16 per Bob's advice. On your lights, math sounds good, but my manufacturer(sold by Van's) states that 16awg is more than enough for 100w halogens. Still went with the 14awg-already had it on hand. Mike H ----- Original Message ----- From: Lincoln Keill To: aeroelectric-list@matronics.com Sent: Friday, January 04, 2008 1:18 AM Subject: AeroElectric-List: sizing wire I'm almost through "The Aero-Electric Connection" and haven't been able to find the "Six-Step Guide to Sizing Wire" so could someone back me up on my methodology before I go off and size every wire of my wiring diagram incorrectly? As an example: I will have a 75W landing light in each wingtip controlled with one switch with a wire run length for each light of 15 feet (including the ground wire from each lamp to the spar). Worst case (alternator out with a 12V battery), each lamp will draw 6.25A so initially you'd think 20 AWG wire would suffice (7A max) but since we want to keep the voltage drop below 0.5V we need to use 16 AWG wire (15 foot resistance of .06 ohms times 6.25A is .38V which is less than 0.50V drop). Since my 16 AWG wire can handle 12.5A, I could safely use a 10A fuse for each light and not worry about the wire burning up or a premature trip when first turning on the lights. Alternatively, I could use 14 AWG wire (15A max) and a single 15A fuse for both lights. The switch should be either a 2-2 (16AWG scenario) or a 1-2 (14AWG scenario) rated for 15A. Whew! Have I got all that correct? As B&J once said: "Thanks for Your Support!" Lincoln Keill Sacramento, CA RV-7A P.S. Can anyone recommend one supplier to get all the goodies for a Z-11 system (wire, switches, fuse blocks, starter & battery contactors, fuse links, shunts, silicon diode array, ground bus blocks,crowbar overvoltage protection, low voltage module, etc. etc.)? ________________________________ Message 18 ____________________________________ Time: 10:53:13 PM PST US From: "B Tomm" Subject: RE: AeroElectric-List: sizing wire LK, You could probably source all that stuff at http://www.bandc.biz/ Click on the yellow link "products". I'm looking at the wiring chart sample that comes with my preview plans. It indicates 14 awg would be the size to go with. This will also allow you to fit 100watt bulbs in the future. Separately fused at 10 amps. Just my .02 cents worth. I'm sure the experts will chime in, in the morning. Bevan Rv7A wiring _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Lincoln Keill Sent: Thursday, January 03, 2008 10:18 PM Subject: AeroElectric-List: sizing wire I'm almost through "The Aero-Electric Connection" and haven't been able to find the "Six-Step Guide to Sizing Wire" so could someone back me up on my methodology before I go off and size every wire of my wiring diagram incorrectly? As an example: I will have a 75W landing light in each wingtip controlled with one switch with a wire run length for each light of 15 feet (including the ground wire from each lamp to the spar). Worst case (alternator out with a 12V battery), each lamp will draw 6.25A so initially you'd think 20 AWG wire would suffice (7A max) but since we want to keep the voltage drop below 0.5V we need to use 16 AWG wire (15 foot resistance of .06 ohms times 6.25A is .38V which is less than 0.50V drop). Since my 16 AWG wire can handle 12.5A, I could safely use a 10A fuse for each light and not worry about the wire burning up or a premature trip when first turning on the lights. Alternatively, I could use 14 AWG wire (15A max) and a single 15A fuse for both lights. The switch should be either a 2-2 (16AWG scenario) or a 1-2 (14AWG scenario) rated for 15A. Whew! Have I got all that correct? As B&J once said: "Thanks for Your Support!" Lincoln Keill Sacramento, CA RV-7A P.S. Can anyone recommend one supplier to get all the goodies for a Z-11 system (wire, switches, fuse blocks, starter & battery contactors, fuse links, shunts, silicon diode array, ground bus blocks,crowbar overvoltage protection, low voltage module, etc. etc.)? ________________________________ Message 19 ____________________________________ Time: 10:59:35 PM PST US From: "B Tomm" Subject: AeroElectric-List: switch rating question If a given double pole switch is rated at 15 amps, is that to mean total, 7.5 amps per pole, 15 amps one pole zero for the other, 15 amps each pole 2X15=30? I'm thinking about a double pole switch for two 100 watt landing lights (one per wing tip). Can I use one switch, 2 poles 2 fuses? Bevan RV7A wiring _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Lincoln Keill Sent: Thursday, January 03, 2008 10:18 PM Subject: AeroElectric-List: sizing wire I'm almost through "The Aero-Electric Connection" and haven't been able to find the "Six-Step Guide to Sizing Wire" so could someone back me up on my methodology before I go off and size every wire of my wiring diagram incorrectly? As an example: I will have a 75W landing light in each wingtip controlled with one switch with a wire run length for each light of 15 feet (including the ground wire from each lamp to the spar). Worst case (alternator out with a 12V battery), each lamp will draw 6.25A so initially you'd think 20 AWG wire would suffice (7A max) but since we want to keep the voltage drop below 0.5V we need to use 16 AWG wire (15 foot resistance of .06 ohms times 6.25A is .38V which is less than 0.50V drop). Since my 16 AWG wire can handle 12.5A, I could safely use a 10A fuse for each light and not worry about the wire burning up or a premature trip when first turning on the lights. Alternatively, I could use 14 AWG wire (15A max) and a single 15A fuse for both lights. The switch should be either a 2-2 (16AWG scenario) or a 1-2 (14AWG scenario) rated for 15A. Whew! Have I got all that correct? As B&J once said: "Thanks for Your Support!" Lincoln Keill Sacramento, CA RV-7A P.S. Can anyone recommend one supplier to get all the goodies for a Z-11 system (wire, switches, fuse blocks, starter & battery contactors, fuse links, shunts, silicon diode array, ground bus blocks,crowbar overvoltage protection, low voltage module, etc. etc.)? ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.