Galvanic Isolator while boat is ashore

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RadiumRob

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The lights on my galvanic isolator are dimly lit while the boat is collected to mains power whilst ashore.

I posted on this a while ago when the boat was in the water, and IIRC it was concluded that a neighbouring boat may have been leaking to earth. Clearly this isn't the case, but what would cause the isolator to be passing current while the boat is ashore?
 
RadiumRob said:
The lights on my galvanic isolator are dimly lit while the boat is collected to mains power whilst ashore.

I posted on this a while ago when the boat was in the water, and IIRC it was concluded that a neighbouring boat may have been leaking to earth. Clearly this isn't the case, but what would cause the isolator to be passing current while the boat is ashore?
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A small fault on board ? Do the lights go out if all shorepower circuits are off?


A faulty GI ?
 
Possibly a faulty GI but could be leaking to ground a bit especially if its wet. A point, in isolation transformers the PE should be bridged so it is not broken by the transformer.
 
David2452 said:
Possibly a faulty GI but could be leaking to ground a bit especially if its wet. A point, in isolation transformers the PE should be bridged so it is not broken by the transformer.
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Maybe i misunderstand you. Surely when using an isolation transformer on the boat the shore PE should terminate at the transformer. It should not be connected to any part of the boat. A neutral should be created on board by connecting one side of the secondary to the boats internal earth system ..... hull with metal boats,
 
When ashore an internal bridge is provided to run the PE direct to the shore earth, see Victron and other IT install manuals.

"If the boat is on shore (winter period or maintenance), the PE conductor in the boat must be connected directly to the input PE, for safety reasons. "
 
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I would turn off each load in turn to see if it is a specific service.

Have you an RCD ? I would expect any significant earth fault would trip this.

I would also check each socket and wired wired appliance for correct connection of live and neutral, including the shore supply itself.

I would then wire a milliamp meter in the earth line at on side of the galvanic isolator (disconnect shore power first) switch on and see what current is flowing. An RCD should trip at 30ma. If greater than 20ma I would want to find the source and remove it.
 
David2452 said:
When ashore an internal bridge is provided to run the PE direct to the shore earth, see Victron and other IT install manuals.

"If the boat is on shore (winter period or maintenance), the PE conductor in the boat must be connected directly to the input PE, for safety reasons. "
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I see .. when ashore.

What safeguards are there to ensure that this connection is removed hen the boat is afloat?
 
VicS said:
I see .. when ashore. What safeguards are there to ensure that this connection is removed hen the boat is afloat?
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Same safeguards as installing the bridge before connecting when ashore, diligence, and in my case a label on the shore power inlet and main switch panel after I have installed them.
 
RadiumRob said:
The lights are on when the main isolating switch is off and all devices are turned off.

The supply is through an RCD, which doesn't trip.

Thanks,
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yes. Sorry I have now found your previous thread. The current through an LED is less than the trip current of the RCD .. a lot less.

I think id systematically disconnect the shorepower working backwards from the isolator looking for what might be causing it, although maybe just not to worry about it

Or contact the makers again.
 
VicS said:
yes. Sorry I have now found your previous thread. The current through an LED is less than the trip current of the RCD .. a lot less.

I think id systematically disconnect the shorepower working backwards from the isolator looking for what might be causing it, although maybe just not to worry about it

Or contact the makers again.
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I will contact the mfr.

There isn't anything upstream of the GI bar the cable - I suppose there could be a defect somewhere causing leakage to ground, but would expect that to be trip the RCD. It may be worth replacing the cable, or at least the plug?
 
Possibly no fault at all. I imagine the warning lights are saying that the boats earth is not reliable connected to the general mass of earth, as a "martindale" tester would......... But that would not explain the original warning lights showing while afloat, was that sorted? I've not read the original thread, are we dealing with Isolating transformer or a galvanic isolator ?



VicS said:
yes. Sorry I have now found your previous thread. The current through an LED is less than the trip current of the RCD .. a lot less.

I think id systematically disconnect the shorepower working backwards from the isolator looking for what might be causing it, although maybe just not to worry about it
Click to expand...
 
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Victron specify that because the transformer is grounded to the boat and not the supply.
Victron transformers can indeed be dangerous in the situation.
Any transformer that is wired correctly with the shield back to the supply the PE does not need bridging.
 
David2452 said:
When ashore an internal bridge is provided to run the PE direct to the shore earth, see Victron and other IT install manuals.

"If the boat is on shore (winter period or maintenance), the PE conductor in the boat must be connected directly to the input PE, for safety reasons. "
Click to expand...


What is the engineering basic principals behind this ?

We constantly see statements about safety setups without the engineering justifications being posted for evaluation.

IMHO no difference to the insulation transformer installation is needed between boat in or out of water.
 
Rogershaw said:
What is the engineering basic principals behind this ?

We constantly see statements about safety setups without the engineering justifications being posted for evaluation.

IMHO no difference to the insulation transformer installation is needed between boat in or out of water.
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As far As I know its only Victron that state this.
The reason Is As follows:
The Victron transformer chassis is earthed to the boat and not the supply, therefore if the supply live becomes disconnected and shorts to the transformer chassis the boat will become live and without bridging the PE there will be no direct earth return path to the supply.
On most other transformers the transformers chassis is earthed to the supply so there is always a direct earth return path.

Victron have been challenged about their wiring but wont admit that its wrong.

ETA their reasoning is that as the transformer is within the boat it should be grounded that way.
My view is that on a steel boat the correct place for an IT is at the supply and not on the boat at all this removes any chance of unisolated power coming in to contact with the boat.
 
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"The Victron transformer chassis is earthed to the boat and not the supply"

Positively lethal IMHO.

Mind you that also applied to generators that have a chassis earthing connection and no neutral to appliance earth wire connection.
 
OK found the original thread and see its a galvanic isolator

A question for VicS Have you any information on Figure 2 on the original thread. I thought galvanic isolators were connect in series as fig 1

mjf107 said:
Possibly no fault at all. I imagine the warning lights are saying that the boats earth is not reliable connected to the general mass of earth, as a "martindale" tester would......... But that would not explain the original warning lights showing while afloat, was that sorted? I've not read the original thread, are we dealing with Isolating transformer or a galvanic isolator ?



VicS said:
yes. Sorry I have now found your previous thread. The current through an LED is less than the trip current of the RCD .. a lot less.

I think id systematically disconnect the shorepower working backwards from the isolator looking for what might be causing it, although maybe just not to worry about it
Click to expand...
Click to expand...
 
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