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<DIV><FONT size=3>Marc,</FONT></DIV>
<DIV><FONT size=3>That was a little more than 50 years ago I tried to use a
piece of inner tube to insulate an attachment on an electric
stock fence. Didn't work, but I learned something very quickly.
Rubber boots insulated you pretty well. If you wanted to check operation
of the fence, you could grab the fence with one hand and touch the other hand to
the ground. You knew right away.</FONT></DIV>
<DIV><FONT size=3>Jim</FONT></DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 7/27/2015 9:11:01 A.M. Central Daylight Time,
personal_submersibles@psubs.org writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>Lots of
carbon black in tire rubber.<BR><BR>Marc<BR><BR>On 7/27/2015 8:28 PM, via
Personal_Submersibles wrote:<BR>> James,<BR>> I've found that some
rubber compounds are conductive. For instance when<BR>> I tried to
electrically insulate with a piece of inner tube from a tyre,<BR>> it still
passed current.<BR>> Jim<BR>> In a message dated 7/27/2015 7:14:28 A.M.
Central Daylight Time,<BR>> personal_submersibles@psubs.org
writes:<BR>><BR>> No. Just sat on the
trailer.<BR>><BR>> On 27 July 2015 at 11:58, Alan via
Personal_Submersibles<BR>>
<personal_submersibles@psubs.org<BR>>
<mailto:personal_submersibles@psubs.org>>
wrote:<BR>><BR>> James were they in the
water?<BR>><BR>> Sent from my
iPad<BR>><BR>> > On 27/07/2015, at
10:33 pm, James Frankland via<BR>>
Personal_Submersibles <personal_submersibles@psubs.org<BR>>
<mailto:personal_submersibles@psubs.org>>
wrote:<BR>> ><BR>>
> Hi All<BR>>
><BR>> > I have a very peculiar
issue. I have an earth fault on the boat.<BR>>
><BR>> > My test
consists of holding one probe of the meter on the<BR>>
positive battery terminal and the other to the hull
somewhere.<BR>> I was showing a reading of
24v. So obviously a negative<BR>>
connection somewhere to the hull.<BR>>
><BR>> > I went around everything
taking things off and have tracked<BR>>
the fault down to the lights.<BR>>
><BR>> > The lights are the
trustfire ones and the negative connection<BR>>
is grounded to the chassis of the light. However, when I
fitted<BR>> the lights, I was aware of
this and so insulated the mounting<BR>>
bracket from the light casing itself with a piece of
rubber.<BR>> So theoretically, there is no
physical connection from the case<BR>> to
the hull. Only the internal wire.<BR>>
><BR>> > Anyway, if I
disconnect the lights and leave them dangling on<BR>>
their wires, there is no earth fault. The lights all work,
and<BR>> the hull is clean of
current.<BR>> ><BR>>
> So the lights must be leaking back through the
connection<BR>> somehow, but I cant see
how. The case is insulated from the<BR>>
mounting bracket with rubber and the brackets are connected
to<BR>> the fibreglass faring, so it
shouldn't leak back?<BR>>
><BR>> > Anyway, ive fixed it by
insulating the mounting bolts with<BR>>
delrin washers, but I cant see how the earth could return<BR>>
through a piece of rubber and then glass fibre. A
mystery<BR>> unless anyone can see
something obvious?<BR>>
><BR>> > Regards<BR>>
> James<BR>>
><BR>> ><BR>>
>
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_______________________________________________<BR>> Personal_Submersibles
mailing list<BR>> Personal_Submersibles@psubs.org<BR>>
http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles<BR>><BR><BR>--
<BR>Archivale catalog: http://www.archivale.com/catalog<BR>Polymath weblog:
http://www.archivale.com/weblog<BR>Translations (ProZ profile):
http://www.proz.com/profile/639380<BR>Translations (BeWords profile):
http://www.bewords.com/Marc-dePiolenc<BR>Ducted fans:
http://massflow.archivale.com/<BR>_______________________________________________<BR>Personal_Submersibles
mailing
list<BR>Personal_Submersibles@psubs.org<BR>http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles<BR></FONT></BLOCKQUOTE></DIV></FONT></BODY></HTML>