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Marina eWof requirements


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Righto, had the inspector from Electra Safe visit today.  Before we got on the boat, I told him that I had no AC equipment installed, to which his reply was "well you don't need an EWOF then".  However, then we got talking about battery chargers and how the power was connected to the charger.  He said that an extension cord coming into the boat was no longer legal and that I must install:

- a plug box in a suitable location, that will accept the "round pin" electrical plugs (female on the boat, obviously)

- hard wired appropriate cabling from there to a (suggested) double plug inside the boat

- that circuit to have a specific type of RCD protector (I don't recall the exact acronym, think it was 16A anyway)

- the AC wiring to be routed separately from the DC

 

I can then plug the battery charger in to that, and have an additional plug to run the vacuum cleaner off, or computer etc.

 

The in-boat electrical work must have a Code of Compliance cert, then be inspected by an inspector for the EWOF.

 

He made two points:

- these regulations are constantly being "improved"

- the regulations vary depending on what equipment is used in what location, as in outside/inside, close to sink, able to be accessed easily etc etc.

 

He wasn't interested in the 12V at all.

 

Anyone know a reasonable sparky who knows boats?

Yup!! This seems very reasonable to me. My current installation is pretty much exactly this and would comply. However this does not comply with NZ 3004.2 which covers ewofs for boats. It's total bollocks and just a paperwork/bureaucracy nightmare. My comments regarding the inspector you get seem well founded.

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Commenting a few ítems above,

The requirement for the AC grounding connection is a requirement of 3004.2 and the US ABYC standards (and I expect the equivalent ISO standard), it is there as a safety requirement in case a phase wire short coricuits and comes in contact with the metallic case of an appliance, it carries this current safely to "ground" ie the sea. It is the same as the ground stake every house has. A galvanic isolator (or better and isolating transformer) is essential in the shore power connection earth wire to keep you electrically isolated from other boats connected to shore power.

It is not widely known that the ground wire must be the same size as the supply wires, this makes life rather difficult with the inverter where you can be talking 50 or 70mm2 cables.

Matt - you need to add a couple of ELCB's to your shopping list, one adjacent to the shorepower connection and another on the inverter output.

The AC installation must be such that the AC power is always synchronised or isolated, ie if you have 2 sources they must be perfectly synchronised eg multiple genrators or generator in parallel with shore power supply. Fortunately we do not have this on our boats and therefore we either follow the protocol Wheels noted, ie only one source at a time (you can this with the slide lockouts on AC switchboards), or run the shorepower AC thru the inverter to the switchboard, as my Mastervolt inverter charger does so. I have an incoming switchboard upstream of the inverter which feeds the inverter and HWC element, the HWC element only runs off shorepower.

One other point is that if you are using and on-board power source ie generator or inverter, then this source must connect the neutral and earth. This should be done automatically but there is some equipment around, especially el-cheapo inverters that do not do so.

The issue with running a power lead into the boat for a singel appliance arises because 3004.2 does not contemplate it. The electrical reg I previously referenced for hand held power tolos should be sufficient but it is not explicit hence the problem. This is further exacerbated by the Electrical Regulations assigning significant authority to Worksafe.

This lack of definition is what leaves us open to all this interpretation by inspectors, who at the end of the day want to ensure their proverbials are covered.

At Sandspit the previous inspector who was frequenting the marina was causing mayhem on the DC side so after some research an inspector was identified who followed the intent of the regs and 3004.2, not try and stretch it out.

Smithy - I am a mechanical engineer with alot of experience in industrial and mining electrical installations. When I upgraded my yacht's electrical systems I did alot of research and discussed requirements with the electricians, did all the DC work myself and all the AC grunt work(running cables and mounting equipment), with the licensed electrician making the connections and testing. So I would not represent myself as an expert, just an above average level of knowledge in this área.

Hi Marinheiro. Thanks for the detailed answer. You certainly have studied hard. Hats off to you!  ABYC standards do not apply to us, so they are out. The reason for earthing that you give is not relevant at all for portable appliances and an extension lead. Any short or leakage of current to earth whether it is via the case of trhe appliance, or via my body, is protected by dual RCDs, one on the dock and one in my boat. The earth from the dock is also connected through to my appliances, so why do I need to earth my boat? What you say would be quite correct if I had a hard wired system through the boat, where a wire could fray and say touch a chainplate or metal object, but that is not the case.. Interesting for sure to discuss these things!!

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Smithy, my comments were in respect of hard wired systems.

I would suggest in your situation installing a basic hard wired system along the lines outlined in Dtwo's posting, noting it will have to be connected to vessel's ground.

It is not going to get any easier dealing with the marina's and it is not unduly expensive.

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So with much fear and trepidation we had booked pork chop in for an ewof inspection. I had a yak to the inspector Tony Murray who was very reasonable. All that we have is a hard wired lead going into a breaker box (with rcd) that feeds a power point. No crazy earthing arrangements and no 12v inspection. It was all ok.

 

 

To avoid any issues with electrolytic corrosion we use a cheap warehouse battery charger that isolates the 12v from 230. Turns out most of the flash chargers don't do that.

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So with much fear and trepidation we had booked pork chop in for an ewof inspection. I had a yak to the inspector Tony Murray who was very reasonable. All that we have is a hard wired lead going into a breaker box (with rcd) that feeds a power point. No crazy earthing arrangements and no 12v inspection. It was all ok.

 

 

To avoid any issues with electrolytic corrosion we use a cheap warehouse battery charger that isolates the 12v from 230. Turns out most of the flash chargers don't do that.

Nice to know the inspectors are treating the issue with common sense, something the Marinas are not! Like IT says, this does not meet the standard, but sounds good to me!!

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Bazza,make sure you use the anode attached to the engine that goes over the side.

When I put that system in it started burning through the anode on the leg. The sparky thought I may have been earthing the whole pier.

Was the simplest system they thought that would be covered by the regs when they installed it, but they did say that they couldnt figure out the regs themselves and that was the best option

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Thanks for that. Since I'm using a charger that has a transformer power supply inside of it instead of a switch mode power supply (eg ctek chargers) the 230v system is isolated from the 12v system.

 

 

This means that there is no risk of electrolytic corrosion through stray currents on the 12v ground back to the marina earth.

 

I dive on the boat regularly for cleaning and there is minimal corrosion on the zinc anode.

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Sounds like a load of shite.

Fortunately after changing to lithium batteries we no longer need to plug the race boat into shore power.

Should also have the cruising boat converted by the time the EWOF expires on that.

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Attached article is in the Westhaven newsletter and easily accessible on the Westhaven Marina website. 

 

Not sure if it simplifies things or not. My boat is very simple electrically and I am feeling somewhat exploited by these new rules if I must do all this so I can plug the battery charger in.

 

a.f.u

 

attachicon.gifElectrical Regs.pdf

I still cannot understand the point of an external Earth when you are running RCDs. Maybe someone can explain the advantage??

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I still cannot understand the point of an external Earth when you are running RCDs. Maybe someone can explain the advantage??

3 reasons. Firstly it helps slightly with the fault loop impedance of the circuit. This ensures that the breaker will trip in a live to neutral short.

 

Also in the unlikely event that you have a broken live conductor touching an unearthed bit of metal on your boat then it can shock you briefly before the rcd trips. Even worse is if u are touching another exposed metal bit that has a frayed neutral conductor touching it. That will likely kill u. Earthing all exposed metal will prevent this.

 

I can't remember what is called, but the last reason is to reduce the likelihood of ground potential. This is basically that when a live conductor falls into the ground/water, but the return path has too much resistance to trip the circuit breaker. This leaves voltage accross the water/ground. Apparently this is more dangerous in fresh water as salt water is far more conductive. It has killed a few people in the US who went swimming in the marina.

 

Realistically, with yearly inspections on the lead and four yearly inspections on the breaker and powerpoint these scenarios are extremely unlikely on a simple system for powering a dehumidifier and a battery charger.

 

However as the system gets more complex I think that the need for more robust protection becomes greater. The issue is where u draw the line I suppose. As it has been pointed out, technically every bit of exposed metal should be bonded to earth including an external bonding plate.

 

Electrical regs are a nightmare.

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1. Not sure how your fault loop impedance theory works. It would be so little difference that it would make no odds, and has nothing to do with having a sea bonding plate! The earth lead bonded to your boat exposed metal is enough.

2. Your exposed metal explanation makes no sense. If your exposed metal is at Phase potential with regard to earth and you grab it, you get a shock as the current path is looking to go to Earth due to our MEN system. If the exposed metal is at neutral potential, you will only get a shock if you are holding a phase wire. If the metal is bonded it is at neutral potential anyway.

2. If you are only running a dehumidifier and a battery charger via an extension lead, your chances of having a phase or neutral conductor earth on a metal item on the boat are slim. The highest risk would probably be through the lead which is inspected anyway.

3. Short circuits are covered by the Breakers on the marina side and on the boat box.

4. Any earth leakage over 30mA will trip the RCD. It is not just a circuit breaker, it measures current in and current out. If the difference is more than 30mA (Or whatever the rating) it trips. There are two of these. One in your boat (In the box that your lead is connected to) and one on the marina dock.

5. This system is not universal. On the ship I work on, we do not run neutral to Earth. Earth is insulated. Any single phase circuit requires breakers/and/or RCDs in both lines as both lines have potential with regard to earth. One of the reasons this is run is that it is SAFER than an MEN system, as you need two faults to get a shock or short circuit..

 

The more you learn, the more you question!! I guess having worked with a lot of electricians who blindly work without any understanding, I always question why, and sometimes they really have to think and research before they answer. I'm not saying I know that much, but I like to ask questions!

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It seems that you are someone who knows a fair bit about electricity, but not as much about NZ electrical regs. To be fair, I haven't read the boat regs, but after talking to the inspector, seeing what is at the marina, and reading what has already been posted here I think I know what they are asking for. The big assumption that I am making here is that boats are required to have a MEN distribution board. IT could confirm/deny this as I am not going to buy a copy just for the sake of this thread.

 

1. Not sure how your fault loop impedance theory works. It would be so little difference that it would make no odds, and has nothing to do with having a sea bonding plate! The earth lead bonded to your boat exposed metal is enough. 

 

You can only install an independent earth (eg sea bonding plate) when it is put in as part of a MEN distribution board as per nz regs. Putting an MEN point in drops the impedance of the fault loop as it now has 2 conductors to go back through, as well as bringing the surrounding "ground" to neutral potential.
 

2. Your exposed metal explanation makes no sense. If your exposed metal is at Phase potential with regard to earth and you grab it, you get a shock as the current path is looking to go to Earth due to our MEN system. If the exposed metal is at neutral potential, you will only get a shock if you are holding a phase wire. If the metal is bonded it is at neutral potential anyway.

 

Think about the insulating properties of our most common boatbuilding material and read my post again.

 

2. If you are only running a dehumidifier and a battery charger via an extension lead, your chances of having a phase or neutral conductor earth on a metal item on the boat are slim. The highest risk would probably be through the lead which is inspected anyway.

 

I completely agree

 

3. Short circuits are covered by the Breakers on the marina side and on the boat box.

 

Yes, but it takes surprisingly little to lift the impedance high enough to start a fire instead of tripping the breaker. A 16A circuit requires a fault loop impedance of less than 1.9 ohms to safely trip the breaker.

 

4. Any earth leakage over 30mA will trip the RCD. It is not just a circuit breaker, it measures current in and current out. If the difference is more than 30mA (Or whatever the rating) it trips. There are two of these. One in your boat (In the box that your lead is connected to) and one on the marina dock.

 

I assume you wrote the first half of that for the sake of anyone following this. At tauranga bridge marina there is no rcd on the dock. I can see where they used to be, but they have been removed. If boats are required to have a MEN distribution board inside of them, then you couldn't have an RCD on the dock without it tripping all the time anyway. This is why I have assumed that the boat regs ask for a MEN distribution board.

 

5. This system is not universal. On the ship I work on, we do not run neutral to Earth. Earth is insulated. Any single phase circuit requires breakers/and/or RCDs in both lines as both lines have potential with regard to earth. One of the reasons this is run is that it is SAFER than an MEN system, as you need two faults to get a shock or short circuit..

 

I am with you on this. I've never been a fan of the MEN system. I won't forget the time I had to convince another electrician that the neutral is an active conductor and needs to be treated as such. Unfortunately it is universal in NZ.

 

The more you learn, the more you question!! I guess having worked with a lot of electricians who blindly work without any understanding, I always question why, and sometimes they really have to think and research before they answer. I'm not saying I know that much, but I like to ask questions!

 

Good on ya. I find that many sparkies think they know what the regs say and how things work, but very few really do. I won't believe what any sparky says that's different to what I already know unless they can point it out to me in the regs.

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More progress today.  Had James from Enertec come and fit the solution as specified by the inspector:

- fixed "round plug" box in cockpit coaming, to accept female plug on (now tagged) shore power lead

- hardwired to twin 240V sockets in sheltered spot below

- RCDO in this line

 

We discussed galvanic isolators, I said I didn't want one and did not feel it necessary as I had no installed AC equipment.  James concurred and we did not fit one.

 

Request in to Electrasafe to inspect and provide final sign-off.  Then I can plug my AC battery charger in and wave 2 fingers at marina management.

 

James was great to deal with, haven't seen the bill but we were all done inside 3 hours.

 

That article from Westhaven does not ring true with what I have learnt in the last few weeks and reads more like an infomercial, IMHO.

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