Westhaven - Shore power leads

[Farrari 4]

Bu**er that didn't work. They want money for it

[JK 28]

Try this link - a draft from 2007.

http://shop.standards.co.nz/drafts/DR07008-DR07008.pdf

[JK 28]

Looking through the doc it seems that the main problem is the requirement to have the conductors supported at regular intervals along their length, and the need to have the earth connection through to the water surrounding the vessel - which is probably where gnasherdogs anode comes in.

[El Toro 97]

Try puttin in a califont these days... LuffyTuffy, guess you just got the bad news as well?

 

Seems all Califonts now have to have external air in and outakes....

 

Look like the wife and child arent getting her hot water for xmas....

[smithy09 50]

OK. Latest standards are AS3004-1 (Marinas) and AS3004-2 (Boats under 50 metres). They were updated in 2008.

 

I have down loaded them at great expense as I am sure I will need them in the future to deal with idiots who abound in the electrical industry. Electrical registration means very little. Experience and knowledge far more...

From a quick skim through, there is very little saying that a perminant installation is required, but if you DO go that route there are a lot of hoops to jump through including the earth bonding of all conductive through hull fittings, so be aware!!

I still cannot see why an extension lead fitted with a 10A breaker/RCCD would not be 100% compliant for a de-humidifier and a battery charger. As soon as you start bonding the hull fittings to earth you are going to have FAR MORE stray earth currents as these are generateed by whatever you plug into your outlets.

This is a can of worms and we should resist it as much as possible from what I can see so far.

I'll read some more when I have time.

[tuffyluffy 76]

Try puttin in a califont these days... LuffyTuffy, guess you just got the bad news as well?

 

Seems all Califonts now have to have external air in and outakes....

 

Look like the wife and child arent getting her hot water for xmas....

 

 

Oh sheeeeet! Id heard that might be an issue. Ducting those suckers is going to be a royal PITA

[Murky 1]

Maybe that explains the references to "caravans" throughout this thread. Once people start seeing a 240v outlet mounted in the boat, they will wonder why they can't have a 200 litre hot water cylinder and a hairdryer for afterwards.

[wheels 543]

Once you understand the way our MEN system works, the reasoning behind the rules are obvious. Just a couple of the points like having to fix the box seems strange to me.

 

The first level of protection we all have, is from the RCD device usually situated at the main supply to each jetty. So if muppet comes along with fryed cord, he, you and me should be protected. An RCD (residual current device), also called in the USA a GFI (ground fault interuptor) will sense a minute electrical current and electronicaly trips a breaker in a fraction of a second. It can sense such a small current that we can not feel it and it trips so fast, we don't feel it. So we are kept safe.

Our eletrical system in NZ is called MEN (multiple Earthed Neutral). At varying points through out NZ's entire electrical supply network, Earth is tied to neutral. The load(electric jug or a light for instance) is between connected between the Phase(thats the hot one) and the Neutral.(please also note that it is NOT positive an negative) A load is not a dead short and as long as it is under the safe operating current draw of the circuit breaker, the load will happily carry out it's task. In NZ, we have a 230V +/- 10% AC supply. The maximum power that can be drawn from a standard three Pin plug is 2400W or 10A. 10 x 240V = 2400W or 2.4Kw.

The Earth is our safety line. It should NEVER be connected to the loads connection point the Nuetral is normally connected to. (For interest, without an RCD, you actually could and you could happily run a load, but you would have no safety line. Because an RCD senses any current flowing in the Earth conductor, it will cause a trip)

If a fault develops in the appliance or the lead supplying it, the Earth is a dead short to the Phase and the breaker trips or blows.

In an installed system, the Mains Earth is also bonded to the DC negative.

The rule is, anything metal that is connected in any conductive way to the boats Negative, MUST be able to be protected by the Mains Earth. So for instance, lets say you have a metal bodied Electic Jug/kettle and the element is faulty and there is a stray current into the water to Earth. (very common by the way). But it could be that the fault is not enough to trip the breaker. (The RCD back at the marina may not trip and I will explain that part soon.) So if you touch the metal of the Kettle, you are now also live with 240VAC. If you in turn now touch some other piece of metal that is bonded to Earth, you now become part of the Earth and are yourself a conductor. And often the only train that leaves the station in this case is you.

Bonding.

First off, A zinc anode is for Galvanic protection of dissimilar metals in the water and should ONLY be bonded to your DC electrical systems Negative. It's purpose is there for the protection of the boat itself, NOT the AC mains. In fact, it can not protect the mains Earth system. There simply is not enough of a circuit through salt water to trip the Circuit breaker. If there was a fault current flowing into the water, the anode would actually fizz away in hrs or even minutes if it were to ever conduct mains voltage to water. If a marine sparky said to fit an anode, it will or should ONLY be for the boats Galvanic protection.

The ONLY time you can have an electrolysis (this is not a galvanic action) problem between boats, is if there is a Voltage leak to the Hull of a boat. This can happen with old battery chargers due to an old design, where a leakage in the charger is then attached to the Negative terminal of the DC system, which of course is tied to the Hull and anode. Now if this boat has a simple power lead in through the hatch and is connected to just a charger and say maybe a Dehumidifier, then there is no Earth bonded to the boat. So now what happens is the stray current on the faulty vessel is seeping away to earth through the water. This is because Earth is tied to the Neutral remember. This is why some Anodes seem to disapear fast. The Salt water and in fact the Seabed the Water is sitting on, is a poor conductor back to where ever the Marinas Earth stake is. That Earth stake is bonding the Earth and Neutral and tying it to the actual Ground and which will be back at the head of the Jetty. So the current is weak, but has a huge potential behind it.

Now bring in all the Boats in the Marina that have installed electrical systems and they all have an Earth conductor fitted. This is a far better conductor than the Saltwater/Seabed. So that fault current will try and find the best conductive path back to that Earth Stake. And that best path will now be the Earth in the water that is closer, which is another Boat. So now we have two or maybe more Boats all losing Anodes faster than normal.

Righty then.so there are two ways that the leakage can be solved. Have an Earth fitted to the boat with the leaky charger, which means installing a fixed system, or disconnect the Earth of the other boats. But wait, we have to have an Earth to keep everyone on board the good boats safe. There are two ways to "isolate" the Earth beween the Boat and the Marina and yet still have the Boat safe. One is the Galvanic isolator. It's an electronic device that simply does not conduct till a small voltage level is obtained and then suddenly conducts. So if no fault exists on the Earth, no voltage flows. As soon as even the smallest current appears on the Earth conductor, the Volatage is the full 230V and so the isolator conducts and connects the Earth to the Marina Earth.

The second means is to have an Isolating Transformer. This isolates the Phase and Neutral from the Marina supply from the Phase and Neutral on the Boat side and thus the Phase and Neutral on the Boat side of the Transformer, is now seperated from the Marina Earth.

But what about that Electric kettle with the leaky element?? Well your boat still has an Earth system. It's just that it us isolated from the Marina, which also means you are isolated from an RCD. So hence the requirement for an RCD on your boat. In the event that a fault occurs that connects your Electronic Isolator, then you don't really want the entire Marina triping out. That RCD is there for a major fault and back up.The RCD on your boat trips at a lower current and slightly faster time, so it should trip before the big girl does up at the Jetty head.

Righty, so I hope that answers it all. If I have confused or forgotten something, Yell.

[Guest]

like this ?

[wheels 543]

It's OSH compliant, because they have gone to a great deal of effort to minimise the hazards.

[Guest]

It's OSH compliant, because they have gone to a great deal of effort to minimise the hazards.

 

The sad thing is you are probably quite right

[Guest]

like this ?

 

Sherm is the guy who is standing on the left.

 

He is immune now

 

BTW Sherm is a lot sharper now that he has been re-wired.

[Guest]

Back up the bus.

 

It appears the Regs don't say we have to do what is being suggested and if we do do it there is a raft of other bollocks that must happen at the same time.

 

There is a suspicion somebody spoke to someone, as opposed to a few, who may have said the Regs say this, but then no one actually checked to see if that was right.

 

Depending on how you read the Regs it looks like all you have to do is change the dehumidifier lead to a real long one and plug that straight in and you're good to go. Don't do that just yet though, reading the Regs is a mindfuck at the best of times so it's still being sussed.

 

Sherm is the guy who is standing on the left.

 

He is immune now

 

BTW Sherm is a lot sharper now that he has been re-wired.

[smithy09 50]

Hi Wheels.

 

All pretty good mate except that an RCCB is a residual current circuit breaker and works on the fact that what goes in should come back (In terms of current). If it doesn't, it is going somewhere else, and therefore trips. You don't need an earth connection to make it work. If you get a combination device that trips on over current and leakage current, you are fully protected, so why isn't a suitable extension lead valid?

I also don't understand the leakage current example you gave. Where does the leakage come from, and why is it not there when the charger is disconnected?

[wheels 543]

Some of the older style chargers use an autotransformer and a selenium rectifier. The transformer is not isolated from the mains supply in the same way a transformer with a seperate primary and secondary is. These chargers are still around and common to come across. You will instant recognise one when you see the rectifier inside, that has the series of metal cooling plates bolted together. But be suspect of any old charger that has a transformer. Not much else inside them.

The more modern chargers today, especially the ones that do multi stage charging have switch mode P/supplies and thus are isolated.

I only gave the charger as an example because it is common to come across in boats in marinas.

But there can be other situations that can also cause leakage. One situation which is not common, is in circuits that have a mains filter capacitor to earth across the on/off switch to stop transient spikes from arcing the switch contacts. A capacitor is a dead short to AC and so it will conduct a small voltage to ground quite happily. Not common, but I have come across the situation. The device was Not on a boat mind you.

 

The RCCD and RCD are the same thing and both work the same way in how they sense a fault. The Phase and Neutral are across the Load and so both equally share the current required to drive that load. If there is a leakage to Earth, then some of that current will conduct along the Earth conductor and because the Earth and the Neutral are bonded, the current in the Neutral is now not the same as on the Phase conductor and the breaker trips. The internals can be slightly different, with some using magnetic coils and some using solid state circuitry.

A plain RCD is not a circuit breaker. It is just an RCD device and will not sense an overload in the circuit. An RCCD will also trip if the load goes beyond the breakers tripping capacity.

[smithy09 50]

Yup, got you, but my point is, that you don't require a bonded earth point on the boat to be safe! The RCD will work fine without it. If you pick up a live appliance, current flows through you to earth. That means there is a current imbalance and the RCD will trip right? So why is a seperate installation on the yacht required to meet the standard? My answer, from what I have read, is that it doesn't and someone has got their wires crossed (pun intended!). I can understand that the lead should have a 10A RCCD and an electrical WOF, but why do you need any more?

I also don't understand how your auto transformer Battery charger is going to leak to earth. I guess I would have to see a circuit diagram..

[wheels 543]

you don't require a bonded earth point on the boat to be safe!

Oh and to add to that, many of the other requirements beng suggested. But it seems that someone is pushing rules that have not been documented.

Actually when we got our boat tested the first time, the Inspecter had no idea of the requirments. I had to talk him through everything. Yet I still got charge the full amount darn it.

[smithy09 50]

Yup! I would think that this one is worth fighting...

[wheels 543]

Actually it brings up a similar question I have had for awhile for Houses. If you have a house pre RCD days, and you now get a new circuit installed, you have to have installed an RCCD on that new circuit. Yet all the original circuits can remain the old way. So why don't they install an RCD on the main feed thus covering the entire installation and keep the simple breaker on each individual circuit.

[smithy09 50]

That's how our house is wired. The main switch on the dist board is an RCCB. I didn't fit it either...