Earth Faults

Hi,

First of all how do you know you actually have an earth fault in your insulated distribution system ( I assume by this wording you mean the negative of your 24V System is not connected to the hull anywhere)

Hi,

That's the answer was looking for.

You are going to have to turn off all your 24V Stuff one circuit at a time till you find the lights stay on the same.

A short cut might be if you know something that has been wet or a squashed/damaged cable amongst your 24V Stuff.

It can be time consuming but there is no really fast way to find it unless you get lucky with what I suggested above.

What is your boat made of?

I would suggest switching off all the circuits and then turn them on and off individually as the fault could be cumulative.

As mentioned above look out for things that can get wet or crushed.

Hi,

Turning everything off isn't a bad idea if you have no idea how long there has been a fault and there maybe several problems, I took it for granted that this guy was paying attention to his monitoring system and this was an early indication.

Also don't forget to include the engines and engine control system in your circuit isolation.

What brand of boat are you dealing with here? I ask this knowing that some well known boat builders use 24V Control for their switchboards and this could be very difficult to isolate in one go.

I once had this problem and it turned out to be the start motor for a Northern Light genset. The shaft inside had come out of position due to a material failure and caused an earth connection. Caused a lot of trouble too...

Because the starter was "tricky" at times, we replaced it and found out.

little hint

Hi
if you have diffs between lights,

1. change the lights ... there are lights with different brightness
2. measure the voltage ... should be the same, if not you have to search


If you have a wiring plan, start at the sources and measure the voltage at all points you can find. if you will find a voltage drop you are now near the leak


I hope this can help a little

For those who have not seen this kind of ground fault indicators, there are normally two yellow lights next to each other on a panel. When they glow with different brightness you have a problem. You can also have a pushbutton which makes them glow equal, to make it easier to see if there is just a small leak. We have had this installed by Alewijnse in Holland.

I had a 24v earth leaks before in the ER of a larger yacht. I turned off all the breakers and looked through every thing I could imagine and came up with nothing. I had 2 contracting electricians then try to help me at seperate times with no luck. I gave up and decided the boat was just going to have to live like that.

Hi everyone,

My two cents:

1. Once I had a 24 V earth fault. Reason found: due to vibration, a "+" cable from battery was slightly damaged and was in touch with ship's hull.

2. Another time it was a battery charger.

3. Then it was in a fire detection system.


I trace such faults beginning with turning off all circuits, one by one.
If no results, start disconnecting lines in 24V system and measure resistances.


The "Earth fault detection system" itself may cause problem as well or give a false indication.

If Your system includes a traffo 220/24 - rectifier, charger then problems may be there.


Just take Your time, trace it logically, excluding circuits step by step.

P.S. Could be great, if You post some scanned drwgs if possible.

rgds,

Andrei

Hi there, be also aware for capacitors used in electronic equipment, they will be showed as an earthfault. Those capacitors are connected between neutral and earth and will be shown as a major fault. Electrospot.

Hi,

Welcome to YF.

You have a good point in your post but I think it has been established here that the fault he is asking about is in the 24V DC System so the capacitors in electronic equipment should not be involved at this stage. When posting here please be aware that some of the people asking questions only have a very basic understanding of what the are asking about which is why they are asking for help. It is easy to confuse by suggesting complicated remedies when it is usually simple things that cause faults like these.

Please don't take my post as a criticism or any sort of personal attack it is not intended as such at all.