Installing shore power, does it have to be earthed?

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SimonA

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I'm looking at installing shore power on my GRP boat used inland (so has to comply with the BSS). One thing that confuses me is the earth arrangement. The 240v will supply a couple of sockets in the cabin, I won't be using a battery charger. Will I need to earth the system to anodes or something?
 
SimonA said:
I'm looking at installing shore power on my GRP boat used inland (so has to comply with the BSS). One thing that confuses me is the earth arrangement. The 240v will supply a couple of sockets in the cabin, I won't be using a battery charger. Will I need to earth the system to anodes or something?
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This had been discussed meany times over on PBO forum and there is different opinions.

My view is that the shore does not need to and should not be connected to a GRP boat (anodes, underwater fittings, etc). But there must be a good external earth coming aboard what is connected to any mains power metal cased items.

I have a steel boat which is very different.

I have 2 neon displays wired earth to neutral (red) that should NOT be on. I have a (green) neon connected live to earth that must be on when shore power is connected.
 
lots or for and against. If you do decide to earth the boat via the anode circuit, fit a galvanic isolator to minimise the chance of any earth related corrosion issues. What you must have is a residual current circuit breaker on the boat before any other circuit breakers. If in future you decide to add a battery charger just make sure it's got floating output i.e the negative connection is not connected to the earth circuit in the charger. (I don't think they are generally)
 
nigelmercier said:
No. Don't even consider it.
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Agree. Absolutely no need to attach to an anode. Just fit a galvanic isolator if you intend leaving plugged in for long periods, but if just to use sockets then that should not be necessary. Make sure you have a proper consumer unit with an RCD.
 
If its not connected to the bonding in the boat what purpose does the galvanic isolator serve? Thats is a question (not a criticism) BTW in case I have a knowledge gap in my understanding. RCD's detect the difference in current between Phase and neutral so that will still work if its not connected to bonding on the vessel. If the bonding is not tethered to the shore supply it cannot be affected by stray currents?
 
Croftie said:
Could you expand on that please
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Well that basis is that with a GRP boat the hull and deck is made from insulating material and thus any metal items bolted to that will be insulated from each other.

With a steel or aluminium boat the hull and deck material will conduct electricity and thus any metal cased appliances will have its case connected to a conductive structure unlike GRP. So with a metal boat if and appliance has a short to case it could make the whole hull and any metal fittings live a cause an electrical shock to anyone touching any metal fitting. So it is imperative to have the hull earthed and a proper RCD to shut off the mains supply if a fault occurs.

On a GRP boat the hull as such will not become live. The only possibility is that a metal cased mains power appliance could become live and not the whole boat

This means that its only metal cased mains appliances that must be connected to the boats earth system and this includes and mains power generator (Inverter of engine driven generator) with a neutral to earth link at rhe inverter/generator .
 
Tranona said:
Agree. Absolutely no need to attach to an anode. Just fit a galvanic isolator if you intend leaving plugged in for long periods, but if just to use sockets then that should not be necessary. Make sure you have a proper consumer unit with an RCD.
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If you don't connect the mains earth to the anodes why to you need a galvanic isolator on a GRP boat.

Also you only need anodes where you have dissimilar metals under water connected together and this is easy to achieve on a GRP boat by not bonding all underwater fittings together.
 
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