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Does shorepower have to plug in to an external socket?   Or can you plug it in on the inside of the boat?

 

Also are there minimum requirements for the shore power lead? And what is a good length?  

 

If there is anything else you think I should know about shore power connections please feel free to mention them.  

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I’ve seen them in lockers etc

Make sure the lead is long enough that it will reach the box irrespective of wether your bow or stern in, then add a bit as some marinas the box may be two along and on the other side.

Mines 1 1/5 times hull length

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Technically it's supposed to be an external socket. Mines not, and it passed inspection. Like lots of this, it depends on your inspector.

Min 2.5mm conductors, and cable supposed to be 5000.1 compliant. Proof of that could be asked for, but again, probably not...

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Technically it's supposed to be an external socket. Mines not, and it passed inspection. Like lots of this, it depends on your inspector.

Min 2.5mm conductors, and cable supposed to be 5000.1 compliant. Proof of that could be asked for, but again, probably not...

The standard does not make reference to the location of the inlet socket, merely states that it shall be rated to IP 56 whether connected to the shore power lead or not. 

 

Mine is an IP56 rated inlet inside a stern locker and has always passed.

 

Interesting discovery on the applicable standard, this is cited in the Electrical Safety Regulations 2010 (with subsequent minor non technical amendments issued 2018) as AS/NZS 3004.2 2008 (without amendment). So the latest revision of the AS/ NZS 3004.2 (2014) does not actually apply where EWOF's are concerned. See here with some interesting comments

https://www.electricalforum.co.nz/index.php?action=more_details&id=1563236892

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So reading that link and this section:

 

 

 

Earthing point / electrode
Again a "boats earth" [ 3.1.3 & 10.1.2 }; being either the boat's hull (if metal) or a metallic part of specified dimensions in contact with water is a requirement that has only existed since 1/4/2010.
ESR 113 says we don't need to upgrade.
App C doesn't specifically require an earth i.a.w 10.1.2; it only requires [ C11.2; subheading earth continuity tests; item 2] that if there's a conductor to such an earth, the max resistance of that conductor is 0.5 ohms. If there's no such conductor, due to having no "boat's earth" then the test is simply not applicable.

 

Does that mean that if it's a new eWOF on an old boat (pre 1/4/2010) that it doesn't need an earth?  Or does it mean that the boat had to have a eWOF prior to 1/4/2010 without an earth?

 

I have heard the specs say that the shore power negative has to be connected to the boat DC negative, but given this isn't earthed to the water it seems to not meet this requirement...

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So reading that link and this section:

 

 

Does that mean that if it's a new eWOF on an old boat (pre 1/4/2010) that it doesn't need an earth?  Or does it mean that the boat had to have a eWOF prior to 1/4/2010 without an earth?

 

I have heard the specs say that the shore power negative has to be connected to the boat DC negative, but given this isn't earthed to the water it seems to not meet this requirement...

Ref your second query, the shore power AC neutral is not directly connected to the boats DC negative, rather the shore power earth is typically connected to the boat's ground which will usually be connected to the DC negative. Metal boats are the exception.

Under the NZ AC supply system (Wheels wrote a long post about this some time ago) the Neutral and the Earth are connected at the point of generation, so in the case of shorepower this connection is made somewhere on shore. If you have on board "generation" by way of an inverter or fixed generator, then this connection takes place within that equipment when it is on line (if they comply with the regs). Portable petrol generators do not comply with this requirement.

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Okay,   so the more I read on this the more its a worm hole of different advice and I think opinion.   If I were to install a shore power system to run my charger 24/7 and the charger would ideally be in a power point so I could you the power point for the odd other thing.  Exactly what do I need,  include plug type, ratings?  So online examples would be great... [i couldn't find 5000.1 compliant three conductor cable online with a quick search]  

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If all you are wanting is to ensure your batteries are kept charged by plugging in a charger and leaving it unattended, don't do it. You will need an EWOF and that will cost you $$$. The subject of EWOFs has been covered extensively in this form, just do a search.

 

Your money would be better spent on solar, which will charge your batteries wherever you are and is more fun to set up. Also, get a tagged extension lead which you can only use on the boat while it is attended.

 

That's just my opinion and will get other options too.

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I agree, solar is cheaper.

 

But, if you really want shore power, then at a minimum;

A proper socket - IP56

lead to a 230v box with RCBO and rev polarity lights, fixed to the boat.

From the RCBO, a lead to either a 230v distribution panel or a power outlet, depending on your requirements.

All cabling must meet the standards (AS/NZS 5000.1, or equivalent - like IEC 60092-353, IEC 60223-3 etc)

The AC ground connects a a single point to the boats DC-, likely the same as the DC ground (engine block etc).

I'd STRONGLY advise a galvanic isolator as well, it interrupts the AC ground to the dock, preventing stray current issues to/from the shore making a circuit.

If you have an inverter, you need a proper distribution panel, with power select switch and lockout.

Total cost is from about 1.5 K up, depending on specific needs, plus install. 

Any decent marine sparky (incl me!) will have, or have access to, the correct cables and equipment, but it must be signed off by an inspector for the ewof...

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The AC ground connects a a single point to the boats DC-, likely the same as the DC ground (engine block etc).

 

Doesn't this also need to be connected to the water via some plate of a specific size? Hence another hole in the boat?

 

Would an inspector actually check that's it's connected to the water with a test?

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No, you only need a ground plate on a commercial vessel, most installs get away with a grounded engine....

Sorry for asking again but I am confused by the definition of grounded. Does grounded mean connected to the water, or is it considered grounded if it is connected to the dc negative?

 

My engine is only going to be grounded to the water via the small amount of water left in impeller housing. Would that be considered "grounded"?

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No, you only need a ground plate on a commercial vessel, most installs get away with a grounded engine....

IT, respectfully wish to differ on this point - all craft require a submerged ground plate to satisfy Equipotential Bonding requirements, ref AS/NZS 3004.2 2008

 

10.1.2 Earthing of the protective conductor in non-metal boats
The protective conductor shall be connected to an earthing electrode that comprises a solid
uncoated conductor having a contact area with the water of at least 0.1 m2, a thickness of at
least 5 mm and a width of at least 20 mm secured to the outside of the hull in an area
reserved for this purpose and located below the light-load water line so that it is immersed
under all conditions of heel.
NOTE: For metallic boats, and particularly those of aluminium alloy, control systems of internal
combustion engines should be insulated from engine earth.
 
I have one of those porous bronze plates and it has been pointed out to me that these are not ideal, the correct plate should be solid copper.
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IT, respectfully wish to differ on this point - all craft require a submerged ground plate to satisfy Equipotential Bonding requirements, ref AS/NZS 3004.2 2008

 

10.1.2 Earthing of the protective conductor in non-metal boats
The protective conductor shall be connected to an earthing electrode that comprises a solid
uncoated conductor having a contact area with the water of at least 0.1 m2, a thickness of at
least 5 mm and a width of at least 20 mm secured to the outside of the hull in an area
reserved for this purpose and located below the light-load water line so that it is immersed
under all conditions of heel.
NOTE: For metallic boats, and particularly those of aluminium alloy, control systems of internal
combustion engines should be insulated from engine earth.
 
I have one of those porous bronze plates and it has been pointed out to me that these are not ideal, the correct plate should be solid copper.

 

Agreed, but most EWOF inspectors will pass them without a ground plate. Maritime NZ inspectors wont....

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Does AS/NZS 3004.2 2008 make provision for where the AC live and neutral has no polarity relative to ocean?

ie isolated.

Not sure if it is exactly what you are asking, the code does permit Non Neutral Earthed Systems (IT System) under certain circumstances when continuity of service is required. It has strict requirements for fault protection and "touch" voltage.

Not likely to be a typical situation for our size of boats 

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I was staying out of this because I though it was all being covered well, but it is getting complicated. Listen to what IT is saying. He understands the rules really well.

When it comes to Earthing, we use the MEN system and do so for several reasons. One being that it eliminates stray currents, while at the same time, allowing the potential of a fault current to flow and thus strip an RCD if they are used.

The use of either an Isolating Transformer or Ground/Galvanic Isolator is about breaking the Earth between Shore power and he Boat. NOTHING ELSE. The Earth MUST REMAIN connected as per normal on the boat. An Isolating TX is just as effective as a Galvanic isolator. The only difference is expense and weight/size.

The Neutral and Earth are once again connected at the circuit board with a cable running to the Engine Block where they meet the Battery Negative. All metals that are in contact with the battery DC system must also be at the same Earth potential. This is so anyone that may come in contact with a mains live device will trip an RCD and maintain electrical protection.

The Earthing plate is an interesting one. It's good to see that a little common sense has occurred in the Industry, but "on paper" there is no clause in the rules that state this is for Commercial only. The idea is that the water surrounding the Boat is at the same Earth potential as the metal components of the Boat. If someone is dangling their feet in the water and touching a SST rail for instance, they should not be able to become the conductor. The chances of a Rail being live on a GRP boat is unlikely. The chances of one being live on a larger commercial vessel is perhaps much higher.

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Good question lateral. But no, the Earth is still separate. Think of it this way. If you generated your own power onboard, your generator and the shore power are two distinctly different systems. The isolator does the same thing. The isolator does the same thing. The power system on the boat can now be thought of as a different system. Even though the Galvanic isolator is using the Neutral and Phase from the shore, the Earth is isolated.

The danger takes place when there is a fault and the fault current is wanting to get back to the shore power Earth. The water then becomes live. But if the Earth and Neutral are connected on the boat, the fault current is kept to within the Circuit Board. The plate is ONLY there to keep the watewr at the circuit board potential and thus metal on the Boat is then the same potential, thus no current flows.

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just for clarification, the Neutral and Earth are only connected on board the vessel when you are generating power on board, by way of a generator or inverter, and this is done within the equipment, not at the switchboard. This connection is open if this equipment is not in service. 

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