[PSUBS-MAILIST] Earth Fault

[James Frankland via Personal_Submersibles]

Hi Emile,

I have a Durite one which has an isolated return.

http://www.ebay.co.uk/itm/Durite-24V-to-12V-Isolated-Dropper-Voltage-Converter-10-Amp-0-578-60-/221693394113?pt=LH_DefaultDomain_3&hash=item339df4bcc1


Regards
James

On 28 July 2015 at 21:49, Emile van Essen via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

>  I overlooked the chassis of the 24 to 12 VDC convertor..
>
>
>
> Emile
>
>
>  ------------------------------
>
> *Van:* Personal_Submersibles [mailto:
> personal_submersibles-bounces at psubs.org] *Namens *James Frankland via
> Personal_Submersibles
> *Verzonden:* maandag 27 juli 2015 12:34
> *Aan:* Personal Submersibles General Discussion
> *Onderwerp:* [PSUBS-MAILIST] Earth Fault
>
>
>
> Hi All
>
>
>
> I have a very peculiar issue.  I have an earth fault on the boat.
>
>
>
> My test consists of holding one probe of the meter on the positive battery
> terminal and the other to the hull somewhere.  I was showing a reading of
> 24v.  So obviously a negative connection somewhere to the hull.
>
>
>
> I went around everything taking things off and have tracked the fault down
> to the lights.
>
>
>
> The lights are the trustfire ones and the negative connection is grounded
> to the chassis of the light.  However, when I fitted the lights, I was
> aware of this and so insulated the mounting bracket from the  light casing
> itself with a piece of rubber.  So theoretically, there is no physical
> connection from the case to the hull.  Only the internal wire.
>
>
>
> Anyway, if I disconnect the lights and leave them dangling on their wires,
> there is no earth fault.  The lights all work, and the hull is clean of
> current.
>
>
>
> So the lights must be leaking back through the connection somehow, but I
> cant see how.  The case is insulated from the mounting bracket with rubber
> and the brackets are connected to the fibreglass faring, so it shouldn't
> leak back?
>
>
>
> Anyway, ive fixed it by insulating the mounting bolts with delrin washers,
> but I cant see how the earth could return through a piece of rubber and
> then glass fibre.  A mystery unless anyone can see something obvious?
>
> Regards
>
> James
>
>
>
>
>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20150729/c4690b81/attachment.html>