240 volt system into yacht

gizzy

gizzy

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Could anyone give me some advice on how to instal a 240 volt system throughout my boat. It will be fed from shore based electrical supply, but I want to instal 3 pin sockets and need advice on whether I need a fuse box, etc.
Many thanks
nigel
 
Yes you need a consumer unit similar to what you have at home.

It should have an RCD and circuit breakers. For use on a boat you should use one with the appropriate degree of water resistance ( IP65)

For a very simple system you will find an inexpensive waterproof ( IP 65) garage consumer unit suitable.

You should fit a galvanic isolator if you will be leaving the boat plugged in even if the shorepower is not in use.

You might like to consider the safety benefits of an isolation transformer ( No GI required then)

ISO 13297 applies to mains power installations in small craft ISO 13297

I would advise you to seek professional advice.
 
it would be handy to have an indication of how complex a job you are considering.

Size/type of boat, number of heavy duty gadgets (e.g. A/c, generator, microwave, how advanced or simple a system you want (standard or programmable logic, and also how much you are ready to do yourself.

Whatever the outcome, your insurance company will be v keen to have the systems inspected and ticked off, and for peace of mind and confidence VicS' recommendation to get a professional involved at the start is best practice.

As I am starting on a maintenance manual for a boat which doesn't have one, a clear set of diagrams showing cable runs, identification tags, sizes, colours, etc. is an essential tool to have on board.
 
You need to think how you're going to fuse the circuits too.
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The consumer unit will have an RCD and several MCBs just like a modern domestic consumer unit.
Individual appliances plugged in to 13 amp sockets will be fused at the plug in the usual way


One of these is a good starting point, as you cannot buy all the bits for less money..
http://www.towsure.com/product/Campi..._Unit_3_Outlet
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its a poor second choice compared with a fixed installation properly done in accordance with ISO 13297 and if you shop around you'll get the same for less than Towsures's price I think you will find. I saw them for £39.99 in Aldi on 19th May.
 
I did this recently and ended up spending around £100 for a couple of sockets, consumer unit, all cable including shore cable and the waterproof connector for the boat. A brief guide to what I did is on the blog linked in my signature. I should note that I missed several things due to the size of boat so I have no onboard earth, no polarity indicator (she will only be used in Britain realistically) but I do have a safe installation which provides for all my needs on board (a real toaster for one!).
Cheers
Dave
 
I have no onboard earth, ..................................................... but I do have a safe installation
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I am not so sure that everyone would agree that you have a safe system if you have no earth connection on board!
 
As Vic says a garage consumer unit (http://www.toolstation.com/shop/p82637) is your starting point; flexible cable to the sockets (2.5mm twin and earth) (http://www.tlc-direct.co.uk/Products/CA2dot5F3slash50.html). I've used standard domestic sockets in the cabins, if worried about water ingress you could use weatherproof ones.
Presuming only 2-3 sockets run a single cable to each from the consumer unit so you dont exceed the cable load.
I use one breaker in the consumer unit for the battery charger and the other for the sockets.
I've never had a GI in the system and not had any probs.
Seek advice as it sounds you are a little inexperienced....
 
lustyd said:
I did this recently and ended up spending around £100 for a couple of sockets, consumer unit, all cable including shore cable and the waterproof connector for the boat. A brief guide to what I did is on the blog linked in my signature. I should note that I missed several things due to the size of boat so I have no onboard earth, no polarity indicator (she will only be used in Britain realistically) but I do have a safe installation which provides for all my needs on board (a real toaster for one!).
Cheers
Dave
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If you have no earth then I guess you must only use double insulated utilities as they only have 2 wires .
 
Perhaps I can tag a little question on here as I am just fitting shore power. No problems with the general installation but need to understand this galvanic isolation a bit and also the earthing. I have an earthing plate on the hull with nothing attached there at the moment, can I just earth to that?
 
pcatterall said:
Perhaps I can tag a little question on here as I am just fitting shore power. No problems with the general installation but need to understand this galvanic isolation a bit and also the earthing. I have an earthing plate on the hull with nothing attached there at the moment, can I just earth to that?
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Unless you are installing an isolation transformer:-

The shore power earth should be bonded to the DC negative and the internal earthing sytem to which the anodes are connected

ISO13297, see my link earlier, describes the requirements. It does, but it is alone among standards to do so, allow you not to bond the earth provided a whole craft RCD is fitted. I have been advised that this "concession" will probably be dropped when the standard is next revised.

If the shorepower is bonded as above and if you leave the boat plugged in to a shorepower supply, even if nothing is actually in use or even if the main isolator is open then a galvanic isolator is more or less essential to prevent corrosion of underwater appendages esp anodes. It functions by blocking currents from low voltage, ie galvanic, sources but allows currents from high voltage sources, ie the mains, to pass.

I imagine your earth plate was fitted for radio equipment or a lightening conductor. It is nothing to do with earthing a shorepower installation.
 
VicS said:
For a very simple system you will find an inexpensive waterproof ( IP 65) garage consumer unit suitable.
Click to expand...

Please note that garage consumer unit IS NOT SUITABLE - unless you change the circuit breaker to be a "twin pole circuit breaker". Reason is that unlike in your garage, someone (you, or the next owner of the boat) may sail the boat to Europe, plug the shore power in a way which reverses the polarity, then if for any reason a circuit breaker blows, it may blow on neutral side. Then, you have a live connector with 240 volts whilst it looks like this is not the case.

So, it is really importat to always fit a "twin pole circuit breaker", which just ensures that both phase and neutral are disconnected simultaneously. This is also written in ISO 13297 section 3.19
double-pole circuit-breaker
device intended to interrupt both the neutral and live conductors in a circuit simultaneously when a designated
current is exceeded for a predetermined time
 
testmonkey said:
Please note that garage consumer unit IS NOT SUITABLE - unless you change the circuit breaker to be a "twin pole circuit breaker". Reason is that unlike in your garage, someone (you, or the next owner of the boat) may sail the boat to Europe, plug the shore power in a way which reverses the polarity, then if for any reason a circuit breaker blows, it may blow on neutral side. Then, you have a live connector with 240 volts whilst it looks like this is not the case.

So, it is really importat to always fit a "twin pole circuit breaker", which just ensures that both phase and neutral are disconnected simultaneously. This is also written in ISO 13297 section 3.19
double-pole circuit-breaker
device intended to interrupt both the neutral and live conductors in a circuit simultaneously when a designated
current is exceeded for a predetermined time
Click to expand...


Are you sure about this?

The consumer units supplied by Merlin Powerstore for shorepower installations appear to have a double pole RCD but single pole mcbs

RCD: Legrand 25A 30mA Double Pole

Breakers: Legrand 16A Single Pole​


The para graph (3.19) you quote from iso 13297 is merely the definition of a double pole circuit breaker.

If you read the main body of the standard they appear to be required on unpolarised systems

7.1.1 In unpolarized systems, double-pole circuit-breakers that open both live and neutral conductors are
required.​

A double pole circuit breaker is however required in the supply to the shorepower circuits

7.2 Main supply circuits

7.2.1 Double-pole circuit-breakers shall be installed in conductors to the shore-power supply circuits.

7.2.2 A manually reset trip-free circuit-breaker shall be installed within 0,5 m of the source of power or, if
impractical, the conductor from the source of power to the panel-board circuit-breaker shall be contained within a
protective covering, such as a junction box, control box, enclosed panel-board, or within a conduit or cable trunking
or equivalent protective covering. If the location of the main shore-power inlet circuit-breaker exceeds 3 m from the
shore-power inlet connection or the electrical attachment point of a permanently installed shore-power cord,
additional fuses or circuit-breakers shall be provided within 3 m of the inlet or attachment point to the electrical
system in the craft, measured along the conductor​

This is surely in addition to the consumer unit with RCD and single pole mcbs for each circuit.

It is curious that the double pole breaker is not included as part of the consumer units but the fact remains that for a simple system a garage unit to IP55 or 65 ( Screwfix offer a couple at around £40 and Toolstation a couple for around £30) may be an alternative to the £90 units offered by Merlin Powerstore.
In both cases the double pole circuit breaker in the incoming supply is another feature.
 
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I've seen fuses in both live and neutral sides of circuits in domestic installations in Europe, I think it was Belgium. It struck me as being a bit of a daft idea because if a circuit's overloaded by a small amount, only one fuse will blow, with a 50-50 likelyhood that it'll be in the neutral, leaving whatever's plugged in live.

I'd rather work to UK standards with a double pole RCD to stop my hair going curly if something goes wrong, plus fuses in the live side and have a system to warn me if the polarity's wrong if I plug in somewhere and their wiring's a bit strange.
 
What I meant by no onboard earth was that earth does not connect to the boat, not that there is no earth. Sorry for the confusion, the earth does indeed pass back to the shore power, and this is generally safer than a second earth on the boat.

The consumer unit I bought was from screwfix and is a garage unit. It does have a dual pole breaker in there and so is more than adequate for a boat installation. In fact it's identical in specification to the ones chandlers sell but half the cost. You'll also need some grommets to go with it which is very rarely mentioned in a bill of materials (they are cheap but essential to keep waterproof).
 
lustyd said:
What I meant by no onboard earth was that earth does not connect to the boat, not that there is no earth. Sorry for the confusion, the earth does indeed pass back to the shore power, and this is generally safer than a second earth on the boat.

The consumer unit I bought was from screwfix and is a garage unit. It does have a dual pole breaker in there and so is more than adequate for a boat installation. In fact it's identical in specification to the ones chandlers sell but half the cost. You'll also need some grommets to go with it which is very rarely mentioned in a bill of materials (they are cheap but essential to keep waterproof).
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Sorry for misunderstanding about the earth.

When you say your Screwfix garage unit has dual pole breaker do you mean it has a two pole over load trip are are you just meaning the RCD. Or does it have a two pole RCBO ( an RCD with overload protection)?
 
2 pole RCBO - the whole kit list is available on this thread.

the unit is here although that doesn't confirm which it is on the page, the manual says RCBO.
Cheers
Dave
 
lustyd said:
2 pole RCBO - the whole kit list is available on this thread.

the unit is here although that doesn't confirm which it is on the page, the manual says RCBO.
Cheers
Dave
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I am not so sure.
As far as i can tell it has a 2 pole RCD and two single pole mcbs

If I understand ISO 13297 correctly you still need a 2 pole circuit breaker on the incoming supply.

The whole unit is described as a RCBO because it does combine the function of RCD and mcb into one box but it does not have two pole overload protection.
 
Well guys, that is all very interesting and I shall be taking some professional advice. My intention was to probably have 5 sockets, 1 for laptop, 1 for phone charger, 1 for kettle, 1 for battery charger and 1 spare. Plus run around 3 LED lights - 'Toaster' !!!! what's wrong with a match.? lol
I did have another thought and that was find a galley slave who could ride a cycle, which is attached by chain to a pulley, which in turn is attached to a flywheel, which is contected to a ..........................................
Seriously guys, please keep the thread going with regard to the 2 pole circuit breaker, I'd like to hear the outcome of the discussion.
Many thanks
Nigel
 
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