Earthing the inverter

[coopec43]

You asked me what sort of Hot Water System I have. It is a Duetto.

https://carac.com.au/products/duoetto-mk2-digital-10l-water-heater-12v-240v?variant=40414586044551&currency=AUD&gad_source=1

[Fore and Aft]

Coopec 43 I originally read your thread and never commented because I knew there would be the "right" way and then the way the majority of my customers do it. For inverter mounting I would say it's split between the engine room or a locker. Rarely do you see an inverter out in the open cabin. Heat dissipation is probably an issue but most inverters I see are in reasonable size lockers. Ours is right next to an air vent and the locker door is far from air tight which would describe most boat lockers. To me under the companion way stairs sounds like a nightmare location. That's one place we stand when wet and taking of our jackets. When there's horizontal rain around its an impossible area to keep dry.
The Duetto hot water heater is fairly common on boats without inboard motors. Which is more efficient heating with 12 or 240 volt?
Cheers

[coopec43]

I need to put a circuit breaker on the positive input lead near the battery. My inverter is 24V 2000W/4000W. Would a 200A circuit breaker be appropriate?

[s/v Jedi]

Originally Posted by coopec43

I need to put a circuit breaker on the positive input lead near the battery. My inverter is 24V 2000W/4000W. Would a 200A circuit breaker be appropriate?

Remember: the fuse or the breaker must protect the wire. So the ampacity of the wire that is used, determines the size of the fuse or breaker.

In this case you need to know the 24V amperage. The manual should tell you what size wire for how many amps you need. This is dependent on the length of the wires. I like to see a minimum voltage drop, 3%.

The answer must be in the manual. With 24V, 100A should be sufficient.

[s/v Jedi]

Originally Posted by GordMay

This can get quite technical, so only consider the following a brief introduction to the subject, and NOT specific advice, on any installation.

In North America the white Neutral wire is also called the “Grounded Conductor”.
The National/Canadian Electric Code [NEC/CEC], and American Boat and Yacht Council [ABYC] standards, require that the green Safety Ground, and the white Neutral wires, in an AC electrical system, MUST be Bonded together at – and ONLY at – the “separately derived source“ of the AC power, being utilized, at any given time.

This means that:

When utilizing Shore Power, the Neutral is bonded to Gnd at the shore power source [the utility], and the boat’s neutral in NOT bonded [on the boat].

When utilizing a separately derived source, such as an onboard Generator, or Inverter, the boat’s Neutral IS bonded to ground [on the boat].
In other words, the frame of a boat’s generator set, or the chassis of a boat’s inverter, are bonded to the boat’s safety ground, only WHEN they are the source of AC power be used, but NOT, when the boat is using shore power.
This requires that the Neutral be connected [bonded], or disconnected [UN-bonded], to ground, depending upon power source selection [Shore, Generator, or Inverter].

In the case of inverters the Neutral is Bonded, ONLY when the inverter is actually producing AC power, and shore power is not available.

Perhaps, these will explain a little more:

The Safety Ground and Neutral Bonding on Boats
➥ https://gilwellbear.wordpress.com/20...ding-on-boats/

The Connection Between Bonding, Grounding And Lightning
➥ https://newboatbuilders.com/pages/electricity14.html

Neutral to Ground Demystified
➥ https://stevedmarineconsulting.com/n...d-demystified/

ABYC/ISO AC-DC grounding requirements [read critically - not all opinions are authoritative]
➥ https://www.cruisersforum.com/forums...-262681-4.html

Good inverters use a relay for grounding the neutral. When the inverter starts up, it grounds the neutral just before supplying output power.

[s/v Jedi]

Coopec,

When you describe what your goal is and what the budget then I can give you much better fitting advice.

For example, I now understand that you do want outlets throughout the boat. This requires an AC distribution panel which is what almost every boat has. But before it was said you use the outlets in the inverter with an extension cable. This is what some boats do, but it’s rare.

Also, I guess in Australia they use the European system with DIN rail mounted breakers etc.? It isn’t hard to build something but you also need space to mount all that. Most boats have a combination AC/DC panel somewhere near the navstation. Do you have this or is this a completely new install? In which case, did you plan a location for the panel?

[coopec43]

Originally Posted by Fore and Aft

Coopec 43 I originally read your thread and never commented because I knew there would be the "right" way and then the way the majority of my customers do it. For inverter mounting I would say it's split between the engine room or a locker. Rarely do you see an inverter out in the open cabin. Heat dissipation is probably an issue but most inverters I see are in reasonable size lockers. Ours is right next to an air vent and the locker door is far from air tight which would describe most boat lockers. To me under the companion way stairs sounds like a nightmare location. That's one place we stand when wet and taking of our jackets. When there's horizontal rain around its an impossible area to keep dry.
The Duetto hot water heater is fairly common on boats without inboard motors. Which is more efficient heating with 12 or 240 volt?
Cheers

Thinking about it overnight I now believe you are right. I'm going to move the inverter about 1 meter to starboard and mount it on the bottom shelf of a galley cupboard. All the galley cupboard doors are louvered so that will allow adequate ventilation. Thanks.

[Wotname]

Originally Posted by coopec43

I wondered about that. What sort of electrician could check what I have done? I have had a house-hold electrician look at the set up and he had no problems. I made sure the galley power point was well above and away from the galley water tap.

Maybe Fore and Aft (who is a Marine Surveyor) could elucidate?

Looks like I need RCDs on all power points? What the most economical way of doing that?


Testing residual current devices


Australian Maritime Safety Authorityhttps://www.amsa.gov.au › domestic-commercial-vessels

16 Oct 2023 — Yearly inspection and testing of RCDs must be done by a competent person such as a licensed electrician or accredited marine surveyor with ...

A couple of times you have asked the question about who can check your mains power 'installation' and have not received a meaningful answer.

If you have ONLY fitted a stand alone inverter with its OWN power outlets, you are good to go. The only electrical connection would have been the 12 or 24 volt DC supply and you can do that yourself. AFAIK, you can use a portable extension lead to extend the mains power to the appliance as required. If the portable extension cord has a switched outlet, it has to have a RCD at the outlet and this should be (must be?) tagged and tested. See https://www.commerce.wa.gov.au/sites...nt-devices.pdf

BUT... if there is any hard wired power outlets, you need a distribution panel, circuit protection (ELCB ect), grounding and so on an so forth. This must be installed and signed off by a licensed electrician. It is unlawful to do it yourself. I think you will be hard pressed to find an electrician to inspect and certify work done by an unlicensed person although you might be lucky. Some electrician might have a look and say 'yeah, looks safe enough' but it is unlikely they would put their name on paper and certify the installation.

As it your recreational boat, you get to choose what risks you are willing to take but if someone gets electrocuted and there is an unapproved mains installation, you may be facing jail time and/or tens of thousands of dollars in fines. Nevertheless, I sure there are a lot of sailboats in Australia with unapproved mains installations.

[coopec43]

Thanks for that Wotname: I think I'm starting get the picture.

When I had Helen berthed at Two Rocks Marina I noticed a message left by the Marina Management attached to the extension cord of the boat in the next berth pointing out the cord had to be certified.. I was waiting to get the same message but it never came. Now I believe they got the message because their boat is a charter boat.

If I had just plugged the extension cord into the inverter and then plugged the microwave into the other end of the extension cord everything would have been OK. BUT when I chopped off the female plug on the extension cord and installed a power point that work requires certification by an expert

Maybe I should remove the power point and replace it with a switched power board instead?
.



I wonder how many boats on Australian waters would meet those standards?

I've asked myself a number of times why does Bunnings (Australia's hardware chain) sell electrical fittings (male/female plugs etc) to the general public when it would be illegal for an unqualified person to fit them?

https://www.obrien.com.au/members/electrical-warana/articles/what-electrical-work-can-i-do-myself-in-australia/

[Wotname]

Originally Posted by coopec43

........
I wonder how many boats on Australian waters would meet those standards?

I've asked myself a number of times why does Bunnings (Australia's hardware chain) sell electrical fittings (male/female plugs etc) to the general public when it would be illegal for an unqualified person to fit them?

https://www.obrien.com.au/members/electrical-warana/articles/what-electrical-work-can-i-do-myself-in-australia/

Both are good questions - I dunno about the first one, maybe some surveyors will have a better idea.

The second one is usually addressed by -

The retailer can't be expected to check who is buying their stuff.
The guy buying it could be getting for his electrician to fit - doesn't want to pay for the time the licensed guy used to purchase the item.
There is no law against selling such products.
The guvmit doesn't want to stifle the free marketplace of selling.

etc etc.

Not a lot of difference between this and household plumbing stuff.

[coopec43]

Maybe I should be viewing a few of these? Surely it can't be too hard wiring up a safe 240V off grid system?

https://www.youtube.com/watch?v=9r8qSokp1Hg

[s/v Jedi]

Originally Posted by Wotname

A couple of times you have asked the question about who can check your mains power 'installation' and have not received a meaningful answer.

If you have ONLY fitted a stand alone inverter with its OWN power outlets, you are good to go. The only electrical connection would have been the 12 or 24 volt DC supply and you can do that yourself. AFAIK, you can use a portable extension lead to extend the mains power to the appliance as required. If the portable extension cord has a switched outlet, it has to have a RCD at the outlet and this should be (must be?) tagged and tested. See https://www.commerce.wa.gov.au/sites...nt-devices.pdf

BUT... if there is any hard wired power outlets, you need a distribution panel, circuit protection (ELCB ect), grounding and so on an so forth. This must be installed and signed off by a licensed electrician. It is unlawful to do it yourself. I think you will be hard pressed to find an electrician to inspect and certify work done by an unlicensed person although you might be lucky. Some electrician might have a look and say 'yeah, looks safe enough' but it is unlikely they would put their name on paper and certify the installation.

As it your recreational boat, you get to choose what risks you are willing to take but if someone gets electrocuted and there is an unapproved mains installation, you may be facing jail time and/or tens of thousands of dollars in fines. Nevertheless, I sure there are a lot of sailboats in Australia with unapproved mains installations.

And here I thought this is exactly what I wrote but I guess you get the wording so much better Maybe I need AI assistance

[Fore and Aft]

Coopec43 you just highlighted why I hate YouTube. What does some Sheila in pink knickers have to do with wiring up an inverter? I am sure one of their 28,000 subscribers will tell me. But tits and arse are not really on the top of my list when I want some information on wiring. I can just see you in a Perth hospital telling the doctor during the most important part of the wiring video you were distracted by some cleavage and butt cheek.
Anyway, I have one of those switchboards in your picture above. It works well and I just reach into the locker and switch the inverter on when we want power.
To reiterate my point about inverter location I took a couple of photos of inverters in boat lockers. Both boats were 17 years old, and it looks like the inverters have been there for years. Thinking about it being close to the batteries seems to be the most common factor when installing an inverter.
Cheers

[coopec43]

I agree with you regarding the Youtube DIY videos featuring scantily clad women trying to explain how to do something. Then again there are videos presented by experts in their trade.(When I got my router the videos were most useful)

After considering all the comments above I will
1. Install the inverter on the bottom shelf of the galley cabinet which is within one meter of the batteries. (the cabinet has louvred doors)
2. Buy X3 plug in RDCs (See picture of the RCD below)
3. Buy X3 Extension cords just the right length. (If they are too long I won't coil them up as it can cause a fire)
4. I will plug the H.W.S and Microwave directly into the extension cords
5. For the galley I will use a power board (as pictured above) which will be fixed to the galley bulkhead with screws in the slots provided..

[sinnerman]

Although ABYC recommends connecting the 120 vac shore power ground (earth) to the same ground as the internal 12 vdc system, I cannot agree with this.

As the prop shaft is grounded (via the engine) to the boat's 12 vdc system, connecting the 120 vac ground to the DC system would now expose the prop shaft and propeller to any AC leakage currents from nearby boats inthe marina.

My two cents.