eWOF in Wellington

[Jason128 6]

Galvanic corrosion happens through DC cabling as well. If you have a galvanic isolator, then the shorepower connection wont make any difference. If you dont, I'd leave the ac ground and DC neg disconnected. However, be warned this is not compliant, and could possibly void your insurance if you had a fire.

I'm not an inspector, if you have an ewof, as a layman that's all that can be expected, and all the marinas ask for.

Its concerning though, that inspectors are signing off unsafe installs....

It’s not just signing it off, this was a new install, done by one of the certified inspectors.

Brief was do what’s required for ewof to tun a dehumidifier and charger continously

[Island Time 1,284]

Bilge pumps in a wet bilge are the cause of the largest percentage of stray current corrosion that I've seen. Often an internal issue in the pump, not a wiring problem.

All batt chargers can fail, but I've only seen 2 of those with issues. They were charging voltage problems , not safety.

[Jason128 6]

Thanks for that island time, Am I right in undersanding in your opinion the battery charger is not a real risk in terms of adding to galvanic corrosion risk?

 

Have sorted the bilge now, no wires sitting in it, and found all the leaks so it’s dry, (ironically it’s raining here, and the house still leaks, bucket in the lounge room, but the boats dry!)

[Island Time 1,284]

I've not actually measured the galvanic voltage with one of those on and off, without a galvanic isolator, so I dont know, sorry.

Most marine sparkies of any competence (including me )will have the appropriate silver/silver chloride half cell so they can measure the galvanic protection in each case, to ensure its within specifications.

[Island Time 1,284]

Matt do you have the oil on 3 phase shore power?

Here you go;

[CutawayCafe 4]

And away we go! Thanks @Island, lots of detail there. @Jason, are you able to share these two eWOF providers for WG?

[wheels 543]

Interesting the comments on the DC not earthed to engine talk. I was going to make a comment on Matts earlier diagram showing the negative of battery banks going to a Bus Bar, when in fact, the Negative should go directly to the Engine Block and the termination point should be at the Starter itself, because that draws the greatest Current. The ALT Neg should also terminate at the starter. The DC neg Bus bar should also terminate at the Starter.
      The engine is earthed, no matter what someone says. If it wasn't, the Starter and ALT would not work. Nor any of the senders for the engine gauges would be working either.
The following is a slightly nerdy answer, but if you read it, it will make sense of the why for you.
   Why the need for a single common ground? Well this is how a "stray" voltage is created. In fact, you engine and electrical system is a circuit absolutely no different to a circuit in your TV or any electronic device. An electronic circuit in a basic description, is the manipulation of an electrical current to do work. Manipulating the Voltages in a circuit, means creating many very small currents from the main supply current. This is simply done via a resistance. A resistance in any circuit causes a Voltage difference to be created across it. That voltage can then be used to do something.
The the case of the Engine/electrical system, the resistances are the lengths of wires, the poor conductor of the engine Cast iron engine block and Salt Water.
If a conductor, lets say a sensor, is connected to the engine block at one end and the Neg from the battery is connected at the other end, what is called a "Voltage Potential" is created due to the engine block not being a fantastic conductor. Now lets consider that there could be many potential sensor connections and lets say the Battery is connected at a different point to the starter etc. Now we have all sorts of stray currents between conductors.
Taking all Earths back to one common point eliminates the various multiple currents flowing in the Engine Block.
In audio, these stray currents are called Earth Loops and result in unpleasant 50Hz hums heard from the speakers.
 

[Black Panther 1,691]

Alternatively add some solar panels and batteries and stay unplugged

[Island Time 1,284]

Interesting the comments on the DC not earthed to engine talk. I was going to make a comment on Matts earlier diagram showing the negative of battery banks going to a Bus Bar, when in fact, the Negative should go directly to the Engine Block and the termination point should be at the Starter itself, because that draws the greatest Current. The ALT Neg should also terminate at the starter. The DC neg Bus bar should also terminate at the Starter.

The engine is earthed, no matter what someone says. If it wasn't, the Starter and ALT would not work. Nor any of the senders for the engine gauges would be working either.

The following is a slightly nerdy answer, but if you read it, it will make sense of the why for you.

Why the need for a single common ground? Well this is how a "stray" voltage is created. In fact, you engine and electrical system is a circuit absolutely no different to a circuit in your TV or any electronic device. An electronic circuit in a basic description, is the manipulation of an electrical current to do work. Manipulating the Voltages in a circuit, means creating many very small currents from the main supply current. This is simply done via a resistance. A resistance in any circuit causes a Voltage difference to be created across it. That voltage can then be used to do something.

The the case of the Engine/electrical system, the resistances are the lengths of wires, the poor conductor of the engine Cast iron engine block and Salt Water.

If a conductor, lets say a sensor, is connected to the engine block at one end and the Neg from the battery is connected at the other end, what is called a "Voltage Potential" is created due to the engine block not being a fantastic conductor. Now lets consider that there could be many potential sensor connections and lets say the Battery is connected at a different point to the starter etc. Now we have all sorts of stray currents between conductors.

Taking all Earths back to one common point eliminates the various multiple currents flowing in the Engine Block.

In audio, these stray currents are called Earth Loops and result in unpleasant 50Hz hums heard from the speakers.

 

Wheels, a small system having the engine block as common ground is good. In a larger system, the regs say you can't have more than 4 connections on a single terminal, and it's common to use a neg bus bar as the common point, and a single good sized (normally 35mm +) cable to the block. These systems normally have a ground plate, also connected to that bus bar. This is the system required by maritime nz, for any commercial vessel.

[wheels 543]

Yes you are correct. I was simply referring to that the circuit drawing you posted earlier did not show the Neg Buss Bar connected to the Engine block. It wasn't really important for the drawing to show and hence why I didn't comment. But when a couple of comments mentioned the engine, I thought perhaps I should comment after all. Certainly nothing you have said has been wrong.

[wheels 543]

 

If you want to run shunts multiple loads  etc battery neg direct to block isn't practical.

You should only have three Neg cables going to the engine. One from Engine start and one from House bank and one back to Neg Bus. Engine start does not need a shunt. You only need a shunt on the House bank which is also the Neg Bus line. The shunt should be close to the Battery as possible/ practical, and no other loads should ever be between it and the Battery terminal.

[CutawayCafe 4]

Currently on Westhaven's website: a marina-endorsed view on modified eboxes --

 

https://www.westhaven.co.nz/westhaven-new/news-events/getting-to-grips-with-electrical-regs/

[Island Time 1,284]

The marina does not give a damn, they just want an EWOF.  You have to have an inspector willing to sign off one if these. They are just an ebox with a polarity light and ground cable, fixed to the boat as I understand it. EAL have an inspector who will do this.

[CarpeDiem 510]

Out of curiosity, why does the shore earth need to be connected to the boat earth if there is no connection between the shore power and the boat DC?  Eg, running just a dehumidifier or any appliance not connected to the DC

 

If you have multiple earth points, should they be connected?  Eg, a Engine/Saildrive and a SSB earthing plate - do these need connection between them?  Does this requirement change with/without shore power?

 

I don't currently have shore power, it is something I am considering adding for just a dehumidifier, but this thread is putting me off ...haha

[Jason128 6]

The eWOF inspectors- - for whoever it was that asked- from the evans bay marina newsletter are

 

 

The process for obtaining an EWOF is –

1)      Electrician inspects boat & remedies any fault.

1 Stop Electrical, Rex Cherrington 022 111 1122

Euro Electrical, Florian 027 245 8889

 

2)      Electrical Inspector inspects & issues EWOF.

John Corbett 027 599 0540

 

 

My understanding is all 3 issue Ewofs, not just the last one

The process for obtaining an EWOF is –

1)      Electrician inspects boat & remedies any fault.

1 Stop Electrical, Rex Cherrington 022 111 1122

Euro Electrical, Florian 027 245 8889

 

2)      Electrical Inspector inspects & issues EWOF.

John Corbett 027 599 0540

[CutawayCafe 4]

Cheers Jason, I asked (Dan). All good, just to note that I asked the marina directly and they gave me a card from Surge (Simon Hoffman), saying that as a result of the EWOF requirement he was inundated. So clearly Surge is endorsed on some level by the Seaview marina for EWOF. That's why I was curious about the two names (which I now understand are known to Evans Bay). I should get out there and chat to Obelix sometime, now I think of it! Good info, especially on the tiered process, thanks!

[Nzgrant 19]

What if you dont have anything but a tagged lead plugged to a multiplug box?

[CutawayCafe 4]

@Nzgrant, others will have better-informed replies, but from a fellow luddite: no EWOF means probably no insurance, which is a liability for the marina plus anyone you bump into/set alight/other. Is there a breaker switch on the multiplug box? Nevertheless, the simplest interpretation of the rule is "no EWOF, no permanent connection" (although a wider literal reading is "no EWOF and/or no insurance equals no berth, regardless of power"). A tagged lead from the pylon to a battery charger and maybe one other device, and plugged into the pylon only while you're aboard, is probably a minimum. 




Marinas state their requirements in broad terms without actually interpreting the standards/rules -- because it's nigh on impossible to get consensus. So we get statements like "permanent power connections must comply in all respects with the relevant regulations". Which is fair enough. I know we have good marina people doing good work, and good boaties living responsibly, but we also have (as evidenced by this and other threads) a wide-open interpretation of a set of rules that may not stand up to a real test (including practicality). And within the muddle, people doing their best based on sometimes wildly differing advice.

 

I looked for the standards, a whopping $160+ for a 60 page document. I've heard two completely different interpretations from experts who've quoted on a friend's vessel.

 

So it comes back to that "living responsibly" bit: My own opinion is, find out what I need to do to be safe first, then (second) find out what else is needed to work in with the marina.

 

Some of us think, sod it, I'll disconnect, rely on solar/wind. But that avoids the real issue of personal safety. IMHO.

[Island Time 1,284]

Got it in one CC, sums up the current shambles pretty well.