Galvanic isolator

[KREW2]

OK. Clearly you aren't simply bringing a roving cable aboard as I and others had assumed. If there is a connection from your earth wire to the sea then a possible place would be from the earthing point in your consumer unit. With the cable disconnected from shore power, open up the consumer unit to check. If no connection there or elsewhere (the earthing point in 240 volt sockets are another slim possibility) then I think it safe to assume there is no connection and that a GI is not needed.

By the way those Marinco plugs have been the cause of fires. Personally, I'd change that.

Sorry to bring this up again.
Today I removed the cover from the consumer unit. The immersion, electric sockets and Sterling 1220 charger are all connected to a common earth, as is the shore power cable.
Should I be looking for another earth wire running off somewhere?

 

[PaulRainbow]

Sorry to bring this up again.
Today I removed the cover from the consumer unit. The immersion, electric sockets and Sterling 1220 charger are all connected to a common earth, as is the shore power cable.

This is correct.

Should I be looking for another earth wire running off somewhere?

Technically yes, but just because there is no additional wire running off to somewhere it does not mean that someone hasn't taken an Earth connection from a socket etc.

Only sure way to check is with a multimeter, to see if there is any continuity between the incoming shore power Earth and the water **

** You can check this at the hull anode (best place, if you have one), shaft, or any other metal object that's in contact with the water.

 

[KREW2]

This is correct.



Technically yes, but just because there is no additional wire running off to somewhere it does not mean that someone hasn't taken an Earth connection from a socket etc.

Only sure way to check is with a multimeter, to see if there is any continuity between the incoming shore power Earth and the water **

** You can check this at the hull anode (best place, if you have one), shaft, or any other metal object that's in contact with the water.

Many thanks

 

[William_H]

GI I believe can be connected in 2 ways firstly in series with the incoming earth wire from jetty. Secondly in series with a connection ring main earth to engine and water. I think the former would be most common and easiest. So possibly your incoming earth wire to your consumer unit may be broken by GI elsewhere. ol'will

 

[VicS]

GI I believe can be connected in 2 ways firstly in series with the incoming earth wire from jetty. Secondly in series with a connection ring main earth to engine and water. I think the former would be most common and easiest. So possibly your incoming earth wire to your consumer unit may be broken by GI elsewhere. ol'will

To provide the required protection against currents from external galvanic sources being carried by the shorepower "earth" conductor the GI must be in series with that incoming shorepower earth

You may have been confused by an alternative I posted a number of years ago purely for discussion. I forget the reasons but it was wrong.

 

[KREW2]

This is correct.



Technically yes, but just because there is no additional wire running off to somewhere it does not mean that someone hasn't taken an Earth connection from a socket etc.

Only sure way to check is with a multimeter, to see if there is any continuity between the incoming shore power Earth and the water **

** You can check this at the hull anode (best place, if you have one), shaft, or any other metal object that's in contact with the water.

Today I removed the earth wire from the boat socket. The meter shows I have continuity to the port prop shaft. I assume this means I need to get a GI.

 

[PaulRainbow]

Today I removed the earth wire from the boat socket. The meter shows I have continuity to the port prop shaft. I assume this means I need to get a GI.

It does indeed. Fit it anywhere between the incoming shore power "socket" and the consumer unit. If you buy one with warning or test lamps, obviously fit it somewhere visible.