---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 01/09/16: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 11:06 AM - Re: Grounding Tabs (Robert L. Nuckolls, III) 2. 12:30 PM - Re: Grounding Tabs (Bill Bear) 3. 01:15 PM - Re: Grounding Tabs (Robert L. Nuckolls, III) 4. 01:58 PM - Re: Grounding Tabs (H. Marvin Haught) ________________________________ Message 1 _____________________________________ Time: 11:06:22 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Grounding Tabs At 08:03 PM 1/7/2016, you wrote: >I think my question may be in need of >adjustment.=C2 I pretty much get the do not s of >grounding the headphones locally.=C2 But my >question still is If=C2 I need to move the forest >of tabs off the firewall by way of a large gauge >wire because I really can't or do not like >running all my no avionics stuff like cockpit >lights,=C2 fuel pumps, panned lights to a local >ground. Does it make sense to use the same gauge >wire=C2 (in this case #6) to relocate the forest >of tabs away from the firewall.=C2 =C2 My engine >and battery are connected to the firewall with >the 5/16 brass bolt.=C2 The 6 gauge wire to the >grounding tabs are also connected to the same >brass firewall bolt.=C2 I will have a few grounds >locally lights etc. but really like the single >point Idea.=C2 Because of the G3x system engine >sensor ho0kup=C2 there is virtually nothing to ground on the firewall side. > >I am pretty much a dummy on this stuff and was >given your book from my life long friend who >runs Central States Ass. Terry, Schubert.=C2 If >It was a Canard EZ I would be in great >shape.=C2 Unfortunately since I am building a "span can" its different. =C2 =C2 The only time you run wire between grounding features for the purpose of achieving a common ground is when only one of those features is fastened to the airframe. As Figures Z-15 shows, the ideal location for the forest of tabs is on the firewall where battery(-) and engine crankcase come to a single point airframe airframe ground. Panel avionics ground need not all run to that point as individual conductors. You gather those wires together locally on the panel with an avionics grounding feature and then extend that feature to the firewall ground with a robust conductor . . . 10 or 12 awg is suggested. So it sounds like you don't even need a forest of tabs at the firewall . . . just the ground stud to handle battery and crankcase grounds. Then use the smaller, more compact grounding hardware to gather up avionics and bring them to that same stud. Bob . . . ________________________________ Message 2 _____________________________________ Time: 12:30:07 PM PST US From: Bill Bear Subject: Re: AeroElectric-List: Grounding Tabs Bob, When another =93grounding bus=94 is used, like an avionics ground bus or a =93panel=94 ground bus, is it necessary to isolate/insolate that ground bus from the =93local=94 ground, or other metal frame on the aircraft, before it is connected to the common firewall ground? It seems to me that you should do that to eliminate other possibilities of ground loops. Bill Bear On Jan 9, 2016, at 5:41, Robert L. Nuckolls, III wrote: > At 08:03 PM 1/7/2016, you wrote: >> I think my question may be in need of adjustment.=C2 I pretty much get the do not s of grounding the headphones locally.=C2 But my question still is If=C2 I need to move the forest of tabs off the firewall by way of a large gauge wire because I really can't or do not like running all my no avionics stuff like cockpit lights,=C2 fuel pumps, panned lights to a local ground. Does it make sense to use the same gauge wire=C2 (in this case #6) to relocate the forest of tabs away from the firewall.=C2 =C2 My engine and battery are connected to the firewall with the 5/16 brass bolt.=C2 The 6 gauge wire to the grounding tabs are also connected to the same brass firewall bolt.=C2 I will have a few grounds locally lights etc. but really like the single point Idea.=C2 Because of the G3x system engine sensor ho0kup=C2 there is virtually nothing to ground on the firewall side. >> >> I am pretty much a dummy on this stuff and was given your book from my life long friend who runs Central States Ass. Terry, Schubert.=C2 If It was a Canard EZ I would be in great shape.=C2 Unfortunately since I am building a "span can" its different. =C2 =C2 > > The only time you run wire between grounding features for > the purpose of achieving a common ground is when only > one of those features is fastened to the airframe. As > Figures Z-15 shows, the ideal location for the forest > of tabs is on the firewall where battery(-) and engine > crankcase come to a single point airframe airframe ground. > > Panel avionics ground need not all run to that point > as individual conductors. You gather those wires together > locally on the panel with an avionics grounding feature > and then extend that feature to the firewall ground > with a robust conductor . . . 10 or 12 awg is > suggested. > > So it sounds like you don't even need a forest of > tabs at the firewall . . . just the ground stud > to handle battery and crankcase grounds. Then > use the smaller, more compact grounding hardware > to gather up avionics and bring them to that same > stud. > > Bob . . . > ________________________________ Message 3 _____________________________________ Time: 01:15:31 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Grounding Tabs At 02:28 PM 1/9/2016, you wrote: >Bob, > >When another "grounding bus" is used, like an avionics ground bus or >a "panel" ground bus, is it necessary to isolate/insolate that >ground bus from the "local" ground, or other metal frame on the >aircraft, before it is connected to the common firewall ground? It >seems to me that you should do that to eliminate other possibilities >of ground loops. I'm going to clarify Z-15 in next revision . . . you're correct that running a ground from panel ground to firewall ground is redundant in a metal airplane. It doesn't hurt anything as long as all the potential victims (avionics and instruments) ground at the single point panel ground. No potentially antagonist loops are created by adding a wire to the firewall . . . it's just redundant. Bob . . . ________________________________ Message 4 _____________________________________ Time: 01:58:50 PM PST US From: "H. Marvin Haught" Subject: Re: AeroElectric-List: Grounding Tabs Bob - I think you answered only half the question. Is it better to isolate the grounding buss, and run a dedicated ground back to the firewall ground, or mount the ground buss to the airframe, and not run a wire back to to the firewall ground? In a metal airplane. Are you more apt to have possible ground loops if you mount the buss to the airframe than you would isolating it from the airframe and running the ground wire back to the firewall ground? M. Haught > On Jan 9, 2016, at 3:14 PM, Robert L. Nuckolls, III wrote: > > At 02:28 PM 1/9/2016, you wrote: >> Bob, >> >> When another =C2=93grounding bus=C2=94 is used, like an avionics ground bus or a =C2=93panel=C2=94 ground bus, is it necessary to isolate/isolate that ground bus from the =C2=93local=C2=94 ground, or other metal frame on the aircraft, before it is connected to the common firewall ground? It seems to me that you should do that to eliminate other possibilities of ground loops. > > I'm going to clarify Z-15 in next revision . . . > you're correct that running a ground from > panel ground to firewall ground is redundant in a metal > airplane. It doesn't hurt anything as long as all > the potential victims (avionics and instruments) > ground at the single point panel ground. No > potentially antagonist loops are created by adding > a wire to the firewall . . . it's just redundant. > > > Bob . . . > ------------------------------------------------------------------------------------- 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.