240V Problem - Shorepower tripping

[Divemaster1]

Fun and games over the last couple of weeks, but have ignored it until now as I have not really needed the pwoer, but now want to resolve...

No problems over the winter, and have had power throughout, but just before launching I noticed that I had no shorepower and had tripped on bollard. Presumed the recent bad weather and water ingress somewhere. (wet and very windy).

1) Shore cable tested and OK
2) Shore cable connected and get power to double 20A fuse on switch panel
3) Swith positive switch seperately and power to other end of fuse
4) swithc Negative and I trip on shore bollard

Now, I thought that I knew where the problem was and disconnected a socket in the roof of engine compartment ( big signs of moisture in box, with connectors badly corroded.... have new outdoor weatherproof socket to replace), cut all wires, isolated them and thought it best to test before connecting up new socket.

.... Still tripping shorepower.

I obviously have a problem here, but should in theory be easy to trace as there are very few things that run on 240V... 3 circuits (which are switched off when tripping)..

1) Sockets (one of which I isolated today with no luck)
2) Boiler (New, and tested, but not isolated yet as it worked fine over a whole week end at time of install )
3) Charger (disconnected and isolated)

.... so guess I am left with testing wires and focus on the negative circuit ....

Any other ideas please ?

 

[Barry Jones]

Have you tried it on another power bollard ??

 

[Divemaster1]

Different Supply

Have you tried it on another power bollard ??

I am afraid that I have... first option I tried... and others were connected to same bollard with no problems, but we tripped.

 

[Barry Jones]

You must be leaking at least around 30mA from the hot side to earth to get this to trip.

This isn't difficult in a damp environment as its a very minute current.

I can't say I can follow all your steps, but you are right in that the key to finding the cause is methodic isolation.

Disconnect everything and then gradually introduce circuits to the incoming supply until the trip in the RCD goes.

I guess it goes without saying to exercise care with 230V supplies.

 

[Divemaster1]

You must be leaking at least around 30mA from the hot side to earth to get this to trip................. Disconnect everything and then gradually introduce circuits to the incoming supply until the trip in the RCD goes.

I guess it goes without saying to exercise care with 230V supplies.

Trouble is, that the other circuits are switched off (seperate fuses).... and it still trips.... now into disconnecting equipment and isolating that from being a cause...

Thanks for the warning, and yes isolated tools circuits tested, re-tested and labelled as I go through. No loose, exposed wires etc. (even down to wearing gloves)...

Think I want to check cable tracks, routes etc., as well when I am at it to remove any doubts arund possible poor connections, damaged wires etc.

... this may take some time ...

 

[Barry Jones]

For what its worth, my advice is to start at the shore input socket and work inwards, systematically isolating each branch, one at a time.

If you have fuses ?? and they are removed in a branch, I cannot see how the RCD could trip through it, unless the earth leakage occurs upstream.

Are you a dive boat ?? mains compressors can be leaky.

 

[carlton]

Dunno if this helps, but I had a similar problem and was stumped.

I eventually found water had seeped into a power point near the galley. Cleaned/dried it out and all was well.

Suggest the incoming water could have 'tracked' along the cable and still be there.

(Oh - and then I remembered it was me who'd spilled some water in the galley earlier that day... )

 

[Divemaster1]

For what its worth, my advice is to start at the shore input socket and work inwards, systematically isolating each branch, one at a time.

If you have fuses ?? and they are removed in a branch, I cannot see how the RCD could trip through it, unless the earth leakage occurs upstream.

Are you a dive boat ?? mains compressors can be leaky.

Intake fuse after intake socket, then on to 20A "twin" fuse/switch in distribution panel (get power to this).... problem occurs when I switch both on distribution panel (individually they are ok, and tested across....but when both positive and negative are switched shore power trips... After main switch at distribution panel, each of the circuits are seperately switched... on positiveside only... and even if they are "off" shorepower trips...

I'll test intake to distribution, but did assumed that as I get clean power to the panel, I assumed that Shore - Shore Cable - Intake to distribution panel was OK.

Not a dive boat ... but have diving equipment onboard, not a compressor though...

 

[Barry Jones]

Not quite sure I understand this bit - normally you have live and neutral with AC and its usual to have double pole switches on the input.

Are you saying that you have two double pole supply breakers on the dist panel and the RCD trips when they are made (even if everything on the individual breakers are switched off ?)

Do you have a circuit diagram for the AC circuit on the boat that you could post on the forum ??

but when both positive and negative are switched shore power trips... After main switch at distribution panel, each of the circuits are seperately switched... on positiveside only... and even if they are "off" shorepower trips...

 

[Divemaster1]

Not quite sure I understand this bit - normally you have live and neutral with AC and its usual to have double pole switches on the input.

Are you saying that you have two double pole supply breakers on the dist panel and the RCD trips when they are made (even if everything on the individual breakers are switched off ?)

Do you have a circuit diagram for the AC circuit on the boat that you could post on the forum ??

Not two double pole switches!! one single, and yes trips when all individual breakers are swithced off.

Goes from intake socket to main intake cabinet, (Fused).... then from there to swich panel. Main intake cabinet have two sources (Generator and Shore) and distribution panel selects source.... not tried to run from generator as I deemed it too risky if fault is downstream..

No diagram, but will make one as I go through the testing...

 

[Barry Jones]

I wouldn't mind betting there is something causing this which gets a supply when the d.p switch is made, but which isn't wired through an individual breaker - something added as an afterthought but no free breakers ??

As said before, the only way is to methodically work through the circuit and draw it out to ensure you don't miss anything.

If worse comes to worse, you might end up disconnecting all the wires and re-connecting one by one to isolate the fault.

 

[Divemaster1]

I wouldn't mind betting there is something causing this which gets a supply when the d.p switch is made, but which isn't wired through an individual breaker - something added as an afterthought but no free breakers ??

As said before, the only way is to methodically work through the circuit and draw it out to ensure you don't miss anything.

If worse comes to worse, you might end up disconnecting all the wires and re-connecting one by one to isolate the fault.

Thanks .... will keep chasing systematically and carefully...

 

[vas]

As said before, the only way is to methodically work through the circuit and draw it out to ensure you don't miss anything.

If worse comes to worse, you might end up disconnecting all the wires and re-connecting one by one to isolate the fault.

Judging from italian car wiring looms, disconnecting everything and re-connecting one by one is probably going to be quicker overall...
Having said that and having checked wirings on a couple of 80ies Italcrafts I'm considering atm, wiring seems better setup than similarly aged princessses...
Is this the case with your beautiful italian lady?

I'd not dare switch the gen, mate with a p410 spend over a grand due to a silly sort that fried the wiring in the 8kva monster in 20secs and needed a crane to lift it off plus a lot of swearing and sweating...

 

[wakeup]

Fun and games over the last couple of weeks, but have ignored it until now as I have not really needed the pwoer, but now want to resolve...

No problems over the winter, and have had power throughout, but just before launching I noticed that I had no shorepower and had tripped on bollard. Presumed the recent bad weather and water ingress somewhere. (wet and very windy).

1) Shore cable tested and OK
2) Shore cable connected and get power to double 20A fuse on switch panel
3) Swith positive switch seperately and power to other end of fuse
4) swithc Negative and I trip on shore bollard

Now, I thought that I knew where the problem was and disconnected a socket in the roof of engine compartment ( big signs of moisture in box, with connectors badly corroded.... have new outdoor weatherproof socket to replace), cut all wires, isolated them and thought it best to test before connecting up new socket.

.... Still tripping shorepower.

I obviously have a problem here, but should in theory be easy to trace as there are very few things that run on 240V... 3 circuits (which are switched off when tripping)..

1) Sockets (one of which I isolated today with no luck)
2) Boiler (New, and tested, but not isolated yet as it worked fine over a whole week end at time of install )
3) Charger (disconnected and isolated)

.... so guess I am left with testing wires and focus on the negative circuit ....

Any other ideas please ?

Are you sure your RCD is ok. I once came across and RCD where there had been a fracture in the back plate and it misbehaved like this. Highly unlikely but we could not track down the fault and went back to the mains board and disassembled and found little crack. I still don't understand how this would effect the RCD functionality but it did. We changed the RCD and problem really did go away.

 

[BartW]

I wouldn't mind betting there is something causing this which gets a supply when the d.p switch is made, but which isn't wired through an individual breaker - something added as an afterthought but no free breakers ??

As said before, the only way is to methodically work through the circuit and draw it out to ensure you don't miss anything.

If worse comes to worse, you might end up disconnecting all the wires and re-connecting one by one to isolate the fault.

was thinking the same,
perhaps there is equipment, installed "pre" individual cirquit brakers,
controll light, isolating transformer, relay,

systematically work through the cirquit is the way to go

 

[johnwest]

In our marina tripping problems are often because of damp / water ingress in the fittings at either end of the shore power cable. So strip both down clean and dry the inside of the plug and socket. This may help.

j

 

[Divemaster1]

Both plugs are new (first thing I replaced), then I tested each of the tree cores, and if there was any damage, which resulted in leakage across... No issues there ... and I get clean power to distribution panel... soproblem is onboard.

Cabeling is very tidy and clear to work with (over sized probably), all cables run in cable trays with removable covers, so will disconnect equipment, then trace cables throughout visually to check for damage when I am at it. Making up a 240V diagram as I go along. This will be a job for next week-endme thinks, as it does involve working outside engines and around the tanks... can see a dirty weekend ahead of me ...

 

[BartW]

Alf,

chances are very low that there is a problem in a tidy, nice and dry cable tray or clean electric enclosure
avoid opening or disassembling these for starters,

suspect old, or wet, or modified electric appliances,

good luck with the dusty job

 

[Divemaster1]

Bingo !!!

Found the circuit !!! Isolated and all's "well"..... got two circuits with what appears as having crossed wires as I have lower voltage across them despite being switched off (so have isolated and aim to re-pull wires or identify where the leakage is....). Result, but more work pending...