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Dave Saylor
Joined: 11 Jan 2015
Posts: 210
Location: GILROY, CA
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 Posted: Sat Jan 17, 2015 6:38 am Post subject: Insulated ground cables? |
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Bob and Listers,
I've been working on a few Beech products lately and a question has come up.
Many of the fuel lines are grounded to the airframe by short, thick ground cables.
Here's a link that shows a typical ground strap. This isn't one of the planes I'm working on, just a convenient snapshot off the internet:
http://www.csobeech.com/images/Baron-FuelSelectorCable.jpg
The question is, why bother to install a ground strap that terminates to an insulated adel clamp?
About all we can figure is that -if- they're for lightning protection, the rubber won't offer much relative resistance.
The practice is consistent across several airplanes. Are we missing something? It's so counterintuitive that there must be a good reason.
--Dave
[quote][b]
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ceengland7(at)gmail.com
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| Posted: Sat Jan 17, 2015 7:38 am Post subject: Insulated ground cables? |
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On 1/17/2015 8:36 AM, David Saylor wrote:
| Quote: | Bob and Listers,
I've been working on a few Beech products lately and a question has
come up.
Many of the fuel lines are grounded to the airframe by short, thick
ground cables.
Here's a link that shows a typical ground strap. This isn't one of
the planes I'm working on, just a convenient snapshot off the internet:
http://www.csobeech.com/images/Baron-FuelSelectorCable.jpg
The question is, why bother to install a ground strap that terminates
to an insulated adel clamp?
About all we can figure is that -if- they're for lightning protection,
the rubber won't offer much relative resistance.
The practice is consistent across several airplanes. Are we missing
something? It's so counterintuitive that there must be a good reason.
--Dave
Just wild speculation, but my 1st guess would be, static dissipation. If
|
there's any carbon in the rubber at all, it would provide a high
resistance path to dissipate any high voltage static charge buildup
caused by the fuel flowing through the line.
Why they wouldn't just pick a spot for the clamp where it could provide
vibration protection to the line at the same time, is another question....
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Dave Saylor
Joined: 11 Jan 2015
Posts: 210
Location: GILROY, CA
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| Posted: Sat Jan 17, 2015 8:34 am Post subject: Insulated ground cables? |
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That's a good theory. I'll post if I get a sure answer.
On Sat, Jan 17, 2015 at 7:37 AM, Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:
[quote]--> AeroElectric-List message posted by: Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)>
On 1/17/2015 8:36 AM, David Saylor wrote:
| Quote: | Bob and Listers,
I've been working on a few Beech products lately and a question has come up.
Many of the fuel lines are grounded to the airframe by short, thick ground cables.
Here's a link that shows a typical ground strap. This isn't one of the planes I'm working on, just a convenient snapshot off the internet:
http://www.csobeech.com/images/Baron-FuelSelectorCable.jpg
The question is, why bother to install a ground strap that terminates to an insulated adel clamp?
About all we can figure is that -if- they're for lightning protection, the rubber won't offer much relative resistance.
The practice is consistent across several airplanes. Are we missing something? It's so counterintuitive that there must be a good reason.
--Dave
|
Just wild speculation, but my 1st guess would be, static dissipation. If there's any carbon in the rubber at all, it would provide a high resistance path to dissipate any high voltage static charge buildup caused by the fuel flowing through the line.
Why they wouldn't just pick a spot for the clamp where it could provide vibration protection to the line at the same time, is another question....
====================================
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Dave Saylor
Joined: 11 Jan 2015
Posts: 210
Location: GILROY, CA
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| Posted: Sat Jan 17, 2015 8:43 am Post subject: Insulated ground cables? |
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I'll look for a contact ribbon. I found this picture. It makes sense.
http://www.interfast.ca/images/115.jpg
On Sat, Jan 17, 2015 at 7:34 AM, <rnjcurtis(at)charter.net (rnjcurtis(at)charter.net)> wrote:
[quote]
Many of the fuel lines are grounded to the airframe by short, thick ground cables.
Here's a link that shows a typical ground strap. This isn't one of the planes I'm working on, just a convenient snapshot off the internet:
http://www.csobeech.com/images/Baron-FuelSelectorCable.jpg
The question is, why bother to install a ground strap that terminates to an insulated adel clamp?
About all we can figure is that -if- they're for lightning protection, the rubber won't offer much relative resistance.
The practice is consistent across several airplanes. Are we missing something? It's so counterintuitive that there must be a good reason.
--Dave
| Quote: | I believe that you will find, if you remove and inspect the Adel clamp, there is a thin metal ribbon woven through the rubber in such a way that it makes contact with the fuel line and the metal structure of the clamp. This will, in fact ground the fuel line.
Roger
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nuckolls.bob(at)aeroelect
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| Posted: Sat Jan 17, 2015 9:06 am Post subject: Insulated ground cables? |
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At 08:36 2015-01-17, you wrote:
Bob and Listers,
I've been working on a few Beech products lately and a question has come up.
Many of the fuel lines are grounded to the
airframe by short, thick ground cables.
Here's a link that shows a typical ground
strap. This isn't one of the planes I'm working
on, just a convenient snapshot off the internet:
http://www.csobeech.com/images/Baron-FuelSelectorCable.jpg
The question is, why bother to install a ground
strap that terminates to an insulated adel clamp?
About all we can figure is that -if- they're for
lightning protection, the rubber won't offer much relative resistance.
The practice is consistent across several
airplanes. Are we missing something? It's so
counterintuitive that there must be a good reason.
--Dave
There is . . .
The padded clamp is for abrasion protection. Micro-vibration
between the tube's surface and mounting (perhaps in combination
with greasy dust) risks erosion of the surface(s) and failure
of the tube.
It doesn't even have to be a 'hard' mounting surface. My
'57 Chevy had a steel brake line resting against a power
steering hose for what had to be years. Oily contaminants
helped gather 'grinding compounds' in the interface. One
night about 1am my brake pedal went to the floor at a stop
sign . . . fortunately out in the country on deserted roads.
I nursed the car into an all night Standard station. The
guy behind the counter was there to pump gas . . . didn't
have a clue as to what might be useful. But he did give me
access to some wrenches and acid core solder I found
in the work bays. I used jumper cables on to hook my hunk
of disconnected brake line across the battery. Got it warm
enough to flow some solder over the hole. But it back on
the car and 'had brakes' albeit a little squishy . . . bubble
in the line.
THAT case was a rubber hose rubbing on a steel tube.
On airplane liquid lines, it's important not only to reduce
the hardness of materials at the clamp up interface (hence
padded clamp) but to make sure the clamp gets a firm grip
on the tube (excludes contaminants and prevents relative
motion). That, brethren, is the reading of THE WORD on
mechanical aspects of liquid line installation.
THE WORD on lightning is found in another book and
discusses an entirely separate constellation of simple
ideas' which drive installation of the bonding straps.
Bob . . .
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yellowduckduo(at)gmail.co
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| Posted: Sat Jan 17, 2015 10:10 am Post subject: Insulated ground cables? |
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On 17/01/2015 12:05 PM, Robert L. Nuckolls, III wrote:
| Quote: |
<nuckolls.bob(at)aeroelectric.com>
At 08:36 2015-01-17, you wrote:
Bob and Listers,
I've been working on a few Beech products lately and a question has
come up.
Many of the fuel lines are grounded to the airframe by short, thick
ground cables.
Here's a link that shows a typical ground strap. This isn't one of
the planes I'm working on, just a convenient snapshot off the internet:
http://www.csobeech.com/images/Baron-FuelSelectorCable.jpg
The question is, why bother to install a ground strap that terminates
to an insulated adel clamp?
About all we can figure is that -if- they're for lightning protection,
the rubber won't offer much relative resistance.
The practice is consistent across several airplanes. Are we missing
something? It's so counterintuitive that there must be a good reason.
--Dave
There is . . .
The padded clamp is for abrasion protection. Micro-vibration
between the tube's surface and mounting (perhaps in combination
with greasy dust) risks erosion of the surface(s) and failure
of the tube.
It doesn't even have to be a 'hard' mounting surface. My
'57 Chevy had a steel brake line resting against a power
steering hose for what had to be years. Oily contaminants
helped gather 'grinding compounds' in the interface. One
night about 1am my brake pedal went to the floor at a stop
sign . . . fortunately out in the country on deserted roads.
I nursed the car into an all night Standard station. The
guy behind the counter was there to pump gas . . . didn't
have a clue as to what might be useful. But he did give me
access to some wrenches and acid core solder I found
in the work bays. I used jumper cables on to hook my hunk
of disconnected brake line across the battery. Got it warm
enough to flow some solder over the hole. But it back on
the car and 'had brakes' albeit a little squishy . . . bubble
in the line.
THAT case was a rubber hose rubbing on a steel tube.
On airplane liquid lines, it's important not only to reduce
the hardness of materials at the clamp up interface (hence
padded clamp) but to make sure the clamp gets a firm grip
on the tube (excludes contaminants and prevents relative
motion). That, brethren, is the reading of THE WORD on
mechanical aspects of liquid line installation.
THE WORD on lightning is found in another book and
discusses an entirely separate constellation of simple
ideas' which drive installation of the bonding straps.
Bob . . .
57 Chevy
|
86 Dodge same thing. Rubber hose OK but it abraded through a steel brake
line below the master cylinder after about 7 years. There were dual
(split) braking systems by 1986 but the emergency brake was more
effective. I also had a rust out on a 88 Dodge and the pedal went to
the floor despite the dual system.
There has been discussion on bad engine ground cables that then allowed
current to flow through control cables or even sensor grounds. I've seen
some aircraft with metal braided fuel lines going to the engine. I
question the wisdom of that and have wondered whether that could have
been a factor in a failed fuel hose and subsequent fatal engine fire a
few years ago. I have two independent ground cables going to my engine
and sure enough I did once find a problem with one of them on an annual
inspection.
I've come across a couple of those adel clamps with integral metal
ground but never thought about them until now. With several rubber hoses
connecting various parts of some fuel systems, it makes sense to bond it
such that no static can possibly build on any part of the system. Must
check this because I think I might have a section of metal tubing all
nicely insulated in Adel clamps, rubber grommets, and rubber hoses.
Ken
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Dave Saylor
Joined: 11 Jan 2015
Posts: 210
Location: GILROY, CA
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| Posted: Sat Jan 17, 2015 10:24 am Post subject: Insulated ground cables? |
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​OK, I understand that using a tight padded clamp will preserve the clampee​. I've repaired much damaged from loose clamps and ty-wraps.
I still don't get, unless it's a conducting clamp, why a bonding strap would be well insulated at one end of the circuit. They're not providing any mechanical connection. Purely electrical so far as I can see.
I may know a lot more after looking closer at the clamp.
--Dave
On Sat, Jan 17, 2015 at 9:05 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
[quote]--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>
At 08:36 2015-01-17, you wrote:
Bob and Listers,
I've been working on a few Beech products lately and a question has come up.
Many of the fuel lines are grounded to the airframe by short, thick ground cables.
Here's a link that shows a typical ground strap. This isn't one of the planes I'm working on, just a convenient snapshot off the internet:
http://www.csobeech.com/images/Baron-FuelSelectorCable.jpg
The question is, why bother to install a ground strap that terminates to an insulated adel clamp?
About all we can figure is that -if- they're for lightning protection, the rubber won't offer much relative resistance.
The practice is consistent across several airplanes. Are we missing something? It's so counterintuitive that there must be a good reason.
--Dave
 There is . . .
 The padded clamp is for abrasion protection. Micro-vibration
 between the tube's surface and mounting (perhaps in combination
 with greasy dust) risks erosion of the surface(s) and failure
 of the tube.
 It doesn't even have to be a 'hard' mounting surface. My
 '57 Chevy had a steel brake line resting against a power
 steering hose for what had to be years. Oily contaminants
 helped gather 'grinding compounds' in the interface. One
 night about 1am my brake pedal went to the floor at a stop
 sign . . . fortunately out in the country on deserted roads.
 I nursed the car into an all night Standard station. The
 guy behind the counter was there to pump gas . . . didn't
 have a clue as to what might be useful. But he did give me
 access to some wrenches and acid core solder I found
 in the work bays. I used jumper cables on to hook my hunk
 of disconnected brake line across the battery. Got it warm
 enough to flow some solder over the hole. But it back on
 the car and 'had brakes' albeit a little squishy . . . bubble
 in the line.
 THAT case was a rubber hose rubbing on a steel tube.
 On airplane liquid lines, it's important not only to reduce
 the hardness of materials at the clamp up interface (hence
 padded clamp) but to make sure the clamp gets a firm grip
 on the tube (excludes contaminants and prevents relative
 motion). That, brethren, is the reading of THE WORD on
 mechanical aspects of liquid line installation.
 THE WORD on lightning is found in another book and
 discusses an entirely separate constellation of simple
 ideas' which drive installation of the bonding straps.
 Bob . . .
====================================
br> fts!)
r> > /www.aeroelectric.com" target="_blank">www.aeroelectric.com
w.buildersbooks.com" target="_blank">www.buildersbooks.com
p.com" target="_blank">www.homebuilthelp.com
e.com" target="_blank">www.mypilotstore.com
" target="_blank">www.mrrace.com
target="_blank">http://www.matronics.com/contribution
     -Matt Dralle, List Admin.
====================================
-
Electric-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
====================================
FORUMS -
_blank">http://forums.matronics.com
====================================
[b]
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Sat Jan 17, 2015 11:19 am Post subject: Insulated ground cables? |
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At 12:23 2015-01-17, you wrote:
| Quote: | ​OK, I understand that using a tight padded
clamp will preserve the clampee​. I've
repaired much damaged from loose clamps and ty-wraps.
I still don't get, unless it's a conducting
clamp, why a bonding strap would be well
insulated at one end of the circuit. They're
not providing any mechanical
connection. Purely electrical so far as I can see.
I may know a lot more after looking closer at the clamp.
|
Any sort of 'conductive' clamp can serve no better purpose
than to mitigate potential differences at LOW current.
I.e. static and maybe noise in radios generated by
itty-bitty arcs due differences across separate airframe
grounds . . . recall that any electrical connection worthy
of the name is gas tight. Lots of pressure, welding, soldering,
crimping, or other joining process intended to exclude
moisture and preserve a BOND. There may be a constellation
of simple-ideas that speak to the utility of 'mildly conducive'
Adel clamps; but not that I've heard/read/observed in my travels.
If design goals for airplane include some level of
survivability to lightning strike, then conductive
bushings in a clamp will not be part of that particular
hardening process.
Bob . . .
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Robert Reed
Joined: 22 Oct 2009
Posts: 331
Location: Dallas/Ft.Worth
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| Posted: Sat Jan 17, 2015 11:44 am Post subject: Insulated ground cables? |
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Test it to see if there a connection.
Bob Reed
Sent from my iPhone
On Jan 17, 2015, at 12:23 PM, David Saylor <saylor.dave(at)gmail.com (saylor.dave(at)gmail.com)> wrote:
[quote]​OK, I understand that using a tight padded clamp will preserve the clampee​. I've repaired much damaged from loose clamps and ty-wraps.
I still don't get, unless it's a conducting clamp, why a bonding strap would be well insulated at one end of the circuit. They're not providing any mechanical connection. Purely electrical so far as I can see.
I may know a lot more after looking closer at the clamp.
--Dave
On Sat, Jan 17, 2015 at 9:05 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>
At 08:36 2015-01-17, you wrote:
Bob and Listers,
I've been working on a few Beech products lately and a question has come up.
Many of the fuel lines are grounded to the airframe by short, thick ground cables.
Here's a link that shows a typical ground strap. This isn't one of the planes I'm working on, just a convenient snapshot off the internet:
http://www.csobeech.com/images/Baron-FuelSelectorCable.jpg
The question is, why bother to install a ground strap that terminates to an insulated adel clamp?
About all we can figure is that -if- they're for lightning protection, the rubber won't offer much relative resistance.
The practice is consistent across several airplanes. Are we missing something? It's so counterintuitive that there must be a good reason.
--Dave
There is . . .
The padded clamp is for abrasion protection. Micro-vibration
between the tube's surface and mounting (perhaps in combination
with greasy dust) risks erosion of the surface(s) and failure
of the tube.
It doesn't even have to be a 'hard' mounting surface. My
'57 Chevy had a steel brake line resting against a power
steering hose for what had to be years. Oily contaminants
helped gather 'grinding compounds' in the interface. One
night about 1am my brake pedal went to the floor at a stop
sign . . . fortunately out in the country on deserted roads.
I nursed the car into an all night Standard station. The
guy behind the counter was there to pump gas . . . didn't
have a clue as to what might be useful. But he did give me
access to some wrenches and acid core solder I found
in the work bays. I used jumper cables on to hook my hunk
of disconnected brake line across the battery. Got it warm
enough to flow some solder over the hole. But it back on
the car and 'had brakes' albeit a little squishy . . . bubble
in the line.
THAT case was a rubber hose rubbing on a steel tube.
On airplane liquid lines, it's important not only to reduce
the hardness of materials at the clamp up interface (hence
padded clamp) but to make sure the clamp gets a firm grip
on the tube (excludes contaminants and prevents relative
motion). That, brethren, is the reading of THE WORD on
mechanical aspects of liquid line installation.
THE WORD on lightning is found in another book and
discusses an entirely separate constellation of simple
ideas' which drive installation of the bonding straps.
Bob . . .
====================================
br> fts!)
r> > /www.aeroelectric.com" target="_blank">www.aeroelectric.com
w.buildersbooks.com" target="_blank">www.buildersbooks.com
p.com" target="_blank">www.homebuilthelp.com
e.com" target="_blank">www.mypilotstore.com
" target="_blank">www.mrrace.com
target="_blank">http://www.matronics.com/contribution
-Matt Dralle, List Admin.
====================================
-
Electric-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
====================================
FORUMS -
_blank">http://forums.matronics.com
====================================
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etienne.phillips(at)gmail
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| Posted: Sun Jan 18, 2015 11:55 pm Post subject: Insulated ground cables? |
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On 17 January 2015 at 21:18, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>
 Any sort of 'conductive' clamp can serve no better purpose
 than to mitigate potential differences at LOW current.
 I.e. static and maybe noise in radios generated by
 itty-bitty arcs due differences across separate airframe
 grounds . . . recall that any electrical connection worthy
 of the name is gas tight. Lots of pressure, welding, soldering,
 crimping, or other joining process intended to exclude
 moisture and preserve a BOND. There may be a constellation
 of simple-ideas that speak to the utility of 'mildly conducive'
 Adel clamps; but not that I've heard/read/observed in my travels.
 If design goals for airplane include some level of
 survivability to lightning strike, then conductive
 bushings in a clamp will not be part of that particular
 hardening process.
 Bob . . .
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Hi Bob et al.
The fuel line is conductive aluminium - why would there be a static build up, unless it were isolated completely from the rest of the airframe by rubber fittings at every support as well as rubber hoses connecting it to the rest of the fuel system? Surely no matter where the pipe is grounded (by connecting it to the fuel tank, gascolator, fuel selector switch or similar), that would dissipate any static build up along the entire length of aluminium piping and anything else connected to it by the AN fittings? I am particularly intrigued by this having _just_ ordered 50' of aluminium fuel piping to refit my Citabria's continuously perishing rubber fuel hoses.
Could it not be as a mechanical restraint in the event of an accident to ensure that when the airframe crumples the pipe bends in a particular fashion to reduce the risk of kinking and spraying fuel all over a fire...?
Thanks
Etienne
Â
[quote][b]
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Mon Jan 19, 2015 5:55 am Post subject: Insulated ground cables? |
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| Quote: | Hi Bob et al.
The fuel line is conductive aluminium - why would there be a static
build up, unless it were isolated completely from the rest of the
airframe by rubber fittings at every support as well as rubber hoses
connecting it to the rest of the fuel system? Surely no matter where
the pipe is grounded (by connecting it to the fuel tank, gascolator,
fuel selector switch or similar), that would dissipate any static
build up along the entire length of aluminium piping and anything
else connected to it by the AN fittings? I am particularly intrigued
by this having _just_ ordered 50' of aluminium fuel piping to refit
my Citabria's continuously perishing rubber fuel hoses.
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Not a static built up WITHIN the tube, but static
currents circulating WITHOUT wherein two conductive
entities are not electrically bonded to each others
and some 'discharge' occurs between them. This is
not a fire safety kind of issue but purely one of
potential noise.
Admittedly, this is an stretch in the extreme to
apply this kind of reasoning to 99 percent of little
airplanes . . . but there are folks who have listened
well to their teachers with experience in high performance,
high altitude and perhaps weapons-grade machines
wherein the slightest risk for mission failure was
treated as a national security issue.
The question that Dave was pondering is probably
not germane to any airplanes that we're interested
in . . . and the narrative supporting the practice
for what he is observing is not readily available
to us.
It's interesting to ponder the value of many of the
process specifications I've encountered over the
years. Beech and Cessna had libraries of them. If
there's a failing of requirements laid out in hard
document (or cultural rules-of-thumb), it's the
dearth of background for why some things are a good
idea and under what conditions they should . . . or
need not be applied.
The authors were long gone and could not be queried
as to the foundation for the practice. Hence, things
that may have been done in good faith and sound
physics on some project years ago have been filtered
down as part of the cultural boiler-plate; dutifully
honored to this day . . . sometimes as more of a
religion than a science. Sorta like the cultural
obsession with oil pressure during the first seconds
of an engine start. Charles Lindbergh may have personally
experience broken oil circulation systems or perhaps
his associates had personal experiences . . . but
what is the likelihood of such an event today?
Most automobiles are fitted with oil pressure switches
that kill the fuel pump when no pressure is sensed.
This prevents a tank mounted pump from driving a
broken fuel line after the engine stops from fuel
starvation. The engine is more likely the become 'inop'
due to fuel plumbing problems (or shorted bus feeder
or smoked electrical system) than for lack of lubrication.
| Quote: | Could it not be as a mechanical restraint in the event of an
accident to ensure that when the airframe crumples the pipe bends in
a particular fashion to reduce the risk of kinking and spraying fuel
all over a fire...?
|
Without published background for a particular
practice, we'll never know for sure. But I think
it's more simplistic. AC43-13 focus is on robust
mounting with allowances for necessary movement while
maintaining clearances between antagonistic components
and mitigating the effects of environment.
The astute systems installer views power steering
hoses, fuel lines, brake lines, control cables,
wire bundles, and all manner of moving parts as
potential antagonists against each other. The
art of their craft includes a running narrative
FMEA pondering all the ways these components may fail
to function due to interference by another component
combined perhaps with an environmental stress.
I used to field worrisome questions about 'exposed'
bus bars behind the panel with the following: "Okay,
with your choice of hammers, saws, clippers or
any other tool, crawl under the panel and do
what ever it takes to bring some part of your
airplane against that exposed bus bar. If you
find some component at risk for such interference,
what is the likelihood of that happening in flight?
If there is strong likelihood, is it better to shield
the bus . . . or improve on the mounting and robustness
of the interfering part?"
From narratives like this . . . and lessons learned
. . . that process specs are crafted and become part of
THE WORD . . . a word often adopted on faith
after the supporting narrative is lost to history.
But we can hone our own awareness of risks by
constantly reviewing the capabilities, limits
and vulnerabilities of components we bolt to our
airplanes. When you bolt in a nice, new, feather
light lithium battery, you ponder . . . "Gee, is
this little feller going to be happy in my airplane?"
When you bundle a bus feeder line together with
come control cables . . . "Hmmmmm . . . can those
guys get each other into trouble like squabbling
two-year-olds?"
The potential for problematic combinations
is huge but they're all based on exceedingly simple
ideas with risks for failure to sift through
the beans for pebbles . . . before the pot goes
on the stove.
Bob . . .
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Dave Saylor
Joined: 11 Jan 2015
Posts: 210
Location: GILROY, CA
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| Posted: Mon Jan 19, 2015 5:58 pm Post subject: Insulated ground cables? |
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Here's a picture of the clamp. It clearly has the contact patch that Roger described.
The fit is not at all tight.Â
It's cabled to the wing skin under a nacelle. The cable attaches to the skin about 1.5" from the bulkhead fitting supporting the tube...
Thankfully, if the tube comes completely disconnected at each end from it's fittings, it still has a path to ground...(kidding).
I still don't know the original intent, but the owner is satisfied that the fuel lines are grounded. Mission accomplished.
Thanks for all the input,
--Dave
[img]cid:ii_14b0502a318424d5[/img]
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_________________
--Dave
KWVI |
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