Investigating electrical leaks (update).

A friend of mine having some minor leaks on his OVNI we discussed how to investigate it and doing so I though it would be worth putting together some kind of comprehensive process description.
This posting is in english because it is the language we used to discuss it.

I updated it as if leaks are not often found they are one of the most difficult thing to diagnose and mot of the time one spend hours (or some time days) discovering where it comes from.
Probably I would have been better to translate it but, beingg lazzy I left it in english, one day may be ...

Hence some methodology is needed and it is all very logical as there is no mystery in this domain.


A - PREPARATION

From the battery bank (BB) identify all the existing connections:

• Normally there should be only one going to the main control panel (CP) by the chart table.
• This his almost never the case as devices that were installed in a second or third phase are usually connected directly to the battery bank like SSB, WaterMaker and so on ....
• Normally there should be only one going to the main control panel (CP) by the chart table.
• Normally there should be only one going to the main control panel (CP) by the chart table.
• The ones that will start/work  are those connected directly and after their cables and connection have been identified it is a good idea to label them and take some pictures.
• >Once this is done all those devices should be disconnected from the BB, up until nothing remains connected, except the CP with all its switches OFF.

In this final position only the leak detector should be left ON.
And if the cables haven't been labelled and are difficult to identify it might be useful to have a digital multimeter, some wire, etc to do some testing.

It is a good idea, at this point, to build a table of all devices and to use it as a checklist for the next steps.

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Exemple 

DEVICE	Direct connection	Connected via CP	Leaks if connected	Leaks if switched ON
Chart plotter		YES	no	no
Mast lights		YES	YES	YES
Water maker	YES		no	YES
SSB Radio	YES		no	no

Direct     : means directly connected,
CP         : means through the Control Panel
Connected  : is (+) if the leaks exists after reconnection 
Swiched ON : is (+) if the leaks appears when the device is switched ON

According to the table, in our test case:
- The chart plotter is OK.
- The mast lights cables definitively have an issue.
- The water maker generate a leak when it runs.
- The SSB is OK.

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B - TEST

B.1 - Direct connection

Now one can manually and carefully re-connect the directly connected devices, one after the other, and each time test for a leak in 2 steps:

1 - after re-connection whilst the device is still switched OFF and
2 - after switching ON the device.

Doing it this way, should help differentiating leaks due to the connection cable from those due to the device itself.
Once tested the device may be kept connected or disconnect for more security but disconnection seems better as it eliminate all possible 'falsly positive'.
Then the result should be logged on the check list and, even if positive, it is almost mandatory to move to the next device as there can be several devices leaking.
Normally, following those steps it should be possible to identify which one is the culprit.

B.2 - Connections through the Control Panel (CP)

Wether a possible culprit has been found or not, at that stage the same process has to be reproduced with the devices connected to through the CP by switching them all, one after the other, and logging the result on the check list.

Here again it is the same 2 steps process:
- Connect through the switch panel, then
- Turn ON
and at each step look for a leak and log the result.

C - RESULTS and LAST CONTROLS

• Normally at this point the leak's origin should have been identified but there could be case where is still there and no culprit has been identified.
• If that's the case, it is worth investigating the connections between the different elements of the Battery Bank as the cables might have been suffering from chafe if not properly protected or fixed.
• If this proves negative then it is time to check if it is not the leak detector that has a problem or if it wrongly wired.

Among the usual suspect are:

The VHF antennas and antenna splitters.
All lights and devices on the mast, including the radar.
The cables from the wind turbine and the solar panels because of chafe.
The SSB radio and any of its components.
The water-maker pumps.
The boiler.
The electrical toilets pump.
The windlass.
The bow-thruster.
The electric winches and furlers.
The alternator.

This is definitely a painful and time consuming exercise but it is worth doing it well by documenting the results by filling the checklist table and taking pictures of the connection after they have been labelled.

Les commentaires sont bienvenus, merci.

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