Marina 'berthmaster' pontoon electricity supply keeps tripping out.

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ChasB

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There was a downpour a couple of days ago while I was aboard and the breaker on the pontoon tripped out. (Of course the rain could just be a coincidence)
I switched off the pontoon power using the Berthmaster website control panel via my phone, reset the pontoon breaker, and switched power on again. Lights came on for a second, then the pontoon tripped out. All breakers on the boat remained untripped.
This happened a second time.
But since then there is no delay and the pontoon breaker trips out immediately if it is switched on. Significantly, this happens even if the main power switch on the boat is off.
Unplugging at the boat, and using a torch (it was getting dark) I expected to see water ingress, but it was bone dry. It was too dark to start taking more stuff apart, so I 'll go back tomorrow.
I tested the boat-to-pontoon lead and running a kettle off it does not trip the pontoon breaker. The lead is ok.
The boat dates from '82, but I put in fresh wiring 10 years ago, along with a Safeshore galvanic isolater.
Tomorrow I'll be taking it apart and looking for signs of water ingress.

My question here: if the boat's main power switch is off then the connection to AC 'live' is isolated at the switch panel (like in a 13A wall cocket) but the neutral and earth are still connected. Could there be something in the boat's electrics that could trip out the pontoon's breaker even if the boat's power is switched off? What should I be looking for?

Many thanks. ;)
 
If the connections in your boat’s power line are shorted at either end of the line then that would trip the pontoon even if the mains switch on you boat is off.

Does the pontoon breaker trip even if your line isn’t even plugged into it? Have you a spare line that you can test it with?

The other places that could be shorted are where the shore line plugs into your boat and where the line from your boat socket is connected to you mains switch.
 
ChasB said:
There was a downpour a couple of days ago while I was aboard and the breaker on the pontoon tripped out. (Of course the rain could just be a coincidence)
I switched off the pontoon power using the Berthmaster website control panel via my phone, reset the pontoon breaker, and switched power on again. Lights came on for a second, then the pontoon tripped out. All breakers on the boat remained untripped.
This happened a second time.
But since then there is no delay and the pontoon breaker trips out immediately if it is switched on. Significantly, this happens even if the main power switch on the boat is off.
Unplugging at the boat, and using a torch (it was getting dark) I expected to see water ingress, but it was bone dry. It was too dark to start taking more stuff apart, so I 'll go back tomorrow.
I tested the boat-to-pontoon lead and running a kettle off it does not trip the pontoon breaker. The lead is ok.
The boat dates from '82, but I put in fresh wiring 10 years ago, along with a Safeshore galvanic isolater.
Tomorrow I'll be taking it apart and looking for signs of water ingress.

My question here: if the boat's main power switch is off then the connection to AC 'live' is isolated at the switch panel (like in a 13A wall cocket) but the neutral and earth are still connected. Could there be something in the boat's electrics that could trip out the pontoon's breaker even if the boat's power is switched off? What should I be looking for?

Many thanks. ;)
Click to expand...
You could have a neutral / earth fault. Do you have an RCCD main switch? Mains isolators isolate both Live and neutral . A picture of your fuse box would be helpful to understand better.
 
Turn off all the on board circuits at the distribution panel but leave the shore power cable connected.and see if the pontoon still trips when you reset it. If it does trip, then there’s a fault somewhere between the boat distribution panel and the pontoon. If it doesn’t trip, then turn the circuits on the boat on one at a time until one of them trips the pontoon.
Whatever you find, you can then investigate the individaual circuit to find and rectify the fault.
 
ChasB said:
There was a downpour a couple of days ago while I was aboard and the breaker on the pontoon tripped out.


My question here: if the boat's main power switch is off then the connection to AC 'live' is isolated at the switch panel (like in a 13A wall cocket) but the neutral and earth are still connected. Could there be something in the boat's electrics that could trip out the pontoon's breaker even if the boat's power is switched off? What should I be looking for?

Many thanks. ;)
Click to expand...

I assume it is actually the pontoon RCD which is tripping , not the circuit breaker tripping on overload . Is that so ?

The boats main isolator should be a double pole switch, isolating both line and neutral .............. The boat's RCD is commonly used for this purpose although if your AC consumer unit / distribution panel which incorporates the RCD is some distance from the the shorepower connector there may be a separate 2 pole isolator within 0.5 metres of the connector.

I assume your galvanic isolator is an installed unit rather than one of the quick plug in units which plugs in with the shorepower ?

From what you have said and already tried it seems that you have a leakage to earth somewhere in the inlet connector or wiring and GI between the connector and the RCD in your main distribution board . Water in the connector is a real possibility. As said above this could be a neutral to earth fault.

An insulation tester such as a "Megger" will be useful in quickly locating the trouble if you can beg, borrow or steal one.
 
Thanks.

I'll get the multimeter out. Unplug everything and do a neutral to earth test. Not sure what level of resistance I should be looking for. I suppose any kind of connection suggests a leak. Then start figuring out where it is.

If that don't work...

Think positive! ;)
 
Thanks, but I have tested the boat-to-pontoon lead and running a kettle off it does not trip the pontoon breaker. The lead is ok.
 
LOL. We've all been there.

The problem is writing something concise that is short enough for folks to actually read without also leaving stuff out, which can then prove even more irritating! ("Why didn't the OP mention that in the first place!" :mad: )

;)
 
ChasB said:
Thanks.

I'll get the multimeter out. Unplug everything and do a neutral to earth test. Not sure what level of resistance I should be looking for. I suppose any kind of connection suggests a leak. Then start figuring out where it is.

If that don't work...

Think positive! ;)
Click to expand...
You really need an insulation tester which applies 350 or 500 volts. ( I believe 500 is now required by 18th edition regs) Then you would be looking for 1 Megohm or higher between the live conductors ( line and neutral) and between either and earth.

Your multimeterr will only apply a very small voltage. ......... Try it. If you get any reading other than infinity investigate.
 
I'm sure you're 100% right. But...
If the pontoon is tripping at 240V then I don't really (in this instance) need to find anything that would show up at 350-500V.
As long as I find the fault and remedy it... ;)
Unless I don't find it, then... :(
 
As mentioned above, I would suggest first to find out if possible exactly what is tripping off, though you may not be able to establish this but worth enquiring. It could could be tripping off due to Over Current or is could be the RCD/RCCB. If this cannot be established then I would start with assuming it was the RCCB as this is the most likely. This means there is an imbalance between the amount of current measured by the RCD on the L and N wires. That amount of difference between more than 30mA (typically). So for example if a L to earth fault existed then there would be less current flowing the N compared to the L. But in your test case the L was isolated so possibly only the N and E are still connected. It could be you have reverse polarity in the supply or what you think is the isolator in the L wire is actually in the N.

But more likely is there is a low level of stray voltage present on the earth, but it is enough voltage to induce a current into a N via a N to E fault. This means the L and N current flows are different so the RCD trips off. Hopefully it is a double pole RCD so the risk of electric shock is completely removed.

It is possible the RCD on shore is faulty, if say more than 15 years old. They do fail. Though one would expect the shoreside RCD to have been tested regularly by the marina.

Answer to Q, Yes, a low resistance between Neutral and Earth will/can trip an RCD/RCCB, but that low resistance could possibly only be detectable when measuring with 230V or more (not what an average 9V multi/voltmeter can do) hence why a special test instrument is needed to make this measurement. Inspection by eye is more likely to find a moisture fault than by using a cheap multimeter. Suggest disconnect the shore power lead completely, double check the power is definitely off, then inspect every 230V electrical termination on board.

As mentioned in another recent thread, if you have an RCD on board that is the same spec as an RCD on shore , then it could be the marginally faster operating RCD on shore will always trip first. The same could apply to an over current MCB.

Probabilities would indicate: you have a Neutral earth fault on board, or you have a L earth fault and the polarity has been reversed, the fault on board could be moisture/wet in a termination somewhere. Most likely the moisture it is the shore connector plug but you have checked that, so next it could be a rain water leak from a window that drips into an electrical fitting. next it could be a failed permanently connected device/appliance such as a Charger, LED light fitting driver, fridge. With out a proper tester then only way to find that is far from ideal but you could be to somehow disconnect them all as close to the item as is practical then step by step reconnect each one until the supply trips. next it could be chaff or vibration that has crushed a cable. BTW rat/mouse damage can cause cable faults like this. Don’t necessarily read anything into the fact that your on board MCB (and RCD if you have one) are not tripping, it could be simply the devices onshore are faster to operate.

Just in case, be ready if it becomes more complicated than just one moisture problem. It could be the there is some moisture in the vesssel power connector on the outside, enough to leak say 15mA to earth, then on board there is another “normal” leakage of say 10mA, then the two added together is enough to trip out a 30mA RCD.

Be very careful or better still get a Pro in.
 
Thanks. Some excellent advice there. ;)

Reverse polarity? LOL Not here. But I have seen some incredible wiring. Rats..?

"With out a proper tester then only way to find that is far from ideal but you could be to somehow disconnect them all as close to the item as is practical then step by step reconnect each one until the supply trips." Exactly what i was thinking.

I've rerouted the pontoon power line to run just the fridge overnight - can't have the milk going off! Was working OK when I left last night.

Many thanks. Will post back with results. Must get off there now while there is light.
 
ChasB said:
Thanks, but I have tested the boat-to-pontoon lead and running a kettle off it does not trip the pontoon breaker. The lead is ok.
Click to expand...
I read that, but I keep coming back to this thread and can't help but suggest you double-check it, if you get the chance.

The shore power lead is the most likely place for water ingress - mine started working again the next morning after the sun came out, and then began tripping the supply again weeks later.

If you can borrow a cable from a neighbour then it's such an easy thing to try, and it's also so very cheap to replace the plug - I like these CeeNorm ones, which seem to be better sealed (see the manufacture's datasheet) than the much more common Walther ones.
 
Good idea that, though they look dry. Thanks. ;) The leakage may be tiny, but added to a small amount on the boat, as our Portsmouth friend explained 4 posts above, it may be enough to trip the breaker. I'm sure the marina office has a spare one.

I've been trying to find water ingress by taking apart everything electrical that's 240V, but (though I've found plenty of other unwelcome stuff! ) everything seems bone dry. So time consuming...

So, would humidity be enough to trigger a sensitive breaker? :unsure:

Another question:
The 12V side of the boat is fed power from batteries charged from a (very nice) Victron Centaur unit which has it's own 13A plug and socket. So when that's unplugged the 12V and 240V boat electrics are completely separate except for a common earth. So am I right that I don't need to bother checking behind the panels of all the 12V stuff? Like on the flybridge? Or is my logic here somehow flawed?

Cheers! :)
 
Last edited:
ChasB said:
Good idea that, though they look dry. Thanks. ;) The leakage may be tiny, but added to a small amount on the boat, as our Portsmouth friend explained 4 posts above, it may be enough to trip the breaker. I'm sure the marina office has a spare one.

I've been trying to find water ingress by taking apart everything electrical that's 240V, but (though I've found plenty of other unwelcome stuff! ) everything seems bone dry. So time consuming...

So, would humidity be enough to trigger a sensitive breaker? :unsure:

Another question:
The 12V side of the boat is fed power from batteries charged from a (very nice) Victron Centaur unit which has it's own 13A plug and socket. So when that's unplugged the 12V and 240V boat electrics are completely separate except for a common earth. So am I right that I don't need to bother checking behind the panels of all the 12V stuff? Like on the flybridge? Or is my logic here somehow flawed?

Cheers! :)
Click to expand...

If it still trips with the onboard isolators turned off you don't need to check anything on the boat, assuming double pole isolators.

It's extremely difficult to give much advice without some additional information.

1) What is tripping ? RCD, MCB, RCBO ? If not sure ask the marina, or can you see what has tripped ?

2\) What is it you are turning off on the boat ? Isolator switch, RCD ? Single or double pole ?

Pics of devices or manufacturers model numbers might help.

I would, as per post #16 try another shore power lead as my first thing, not last thing.
 
ChasB said:
I'm sure you're 100% right. But...
If the pontoon is tripping at 240V then I don't really (in this instance) need to find anything that would show up at 350-500V.
As long as I find the fault and remedy it... ;)
Unless I don't find it, then... :(
Click to expand...
The reason the Megger must be at 500v on a 240vac system is because '240' is the RMS (Root of the Mean of the Square - or effectively the average value of the AC voltage), but the system test must be exposed to the peak voltage, which for 240vac is 339 volts (or higher if the actual voltage is higher than the nominal rating of the supply (UK 240v can rise to 253v and still be legally compliant), so 500 v is the next test meter index voltage above this. The megger puts the system under a 500v DC voltage and the meter measures the current flow at that voltage to work out and hence display the resistance at the test voltage.

This would need to be at least 20 Meg Ohms and ideally > 50 Meg ohms. A fault exists below 2 Meg ohms and between 2 - 20 dampness could be causing an issue. The 30 ma trip will require a resistance well below this ~ 8 k Ohms.

A faulty circuit will rapidly fall way below the 8 k ohms level.

But the issue with an RCD tripping is generally 30 milliamps, just enough to give someone a tingle but generally not a lethal electric shock.

The test is to measure the resistance between the neutral & earth and live & earth condiuctors. But make sure any electronic equipment is isolated first, otherwise the 500v DC can cause component damage.
 
Thanks guys. Such a helpful and useful forum this! ;)

Currently awaiting delivery of a brand new lead. No point in taking the boat further apart until I've exhausted that.

Well, I suppose this gives me something to do over Xmas... :confused:
 
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