Trek forum posts in last 60 days

No worries Shaggy. I had a head start on the subject. For the last 12 months ensuring electrical safety of sensors attached to a laser going into peoples lungs to treat cancer. Much smaller space and tiny current 10uA instead of 10A but same principle :-)
In theory if Lazz connected the Ground pin on his inverter to the hull via one of these au.mouser.com/ProductDetail/KEMET/R474N31005001K?qs=MdJgNetHbfmbEG0LDSqYUg%3D%3D it should meet the floating standard and also let the inverter EMI filter continue to reasonably work. Its an X2 safety capacitor. Its guaranteed to fail open circuit not short circuit.
But I think hes probably fallen asleep after all this!

In Australia, standard AS/NZS3004.2 Electrical installations: Marinas and boats - Boats

Floating system is the normal requirement. For most boats, the AC system must be electrically isolated from the hull and DC system, meaning: Neutral is NOT bonded to earth onboard Earth is NOT bonded to the hull[ (for non-metal boats) The shore earth is carried onboard only for fault protection, not bonding The system is therefore floating with respect to the hull This applies especially to: Fibreglass boats Timber boats Composite boats Boats on marina shore power. Safety is achieved via RCDs and isolation, not by tying AC to the hull. RCDs are mandatory.

Sorry, but the can of worms is getting longer.... just to check my plan - if it was me - with a 240VAC inverter not to connect the Earth pin (ie in electrical terms create a floating power system) wasn't totally flawed I checked with the famous Chatgpt.

Notice the very last line. Also use RCDs everywhere.

Here are five boat types where the 240 VAC system is commonly electrically floating. (no bond between neutral and hull/earth on the vessel itself). This is standard practice to reduce corrosion risk and avoid marina earth-loop issues: Fibreglass sailing yachts GRP hull = electrically non-conductive Shore power earth is isolated from DC negative and hull Neutral is not bonded onboard (bonding only occurs ashore via the supply transformer) Catamarans (fibreglass or composite) Same principles as monohull GRP yachts Floating AC system reduces stray current corrosion between twin hulls Very common in cruising and charter cats Luxury motor yachts (GRP or composite hulls. Especially those with isolation transformers or gensets AC system typically floats with controlled bonding points Neutral-earth bond occurs only at generator or shore transformer, not the hull Wooden boats and classic wooden yachts Hull is non-conductive AC earth kept isolated from hull and DC system Floating systems reduce electrolytic damage to fastenings Offshore cruising yachts with inverter-based AC systems. Inverter output is floating when not connected to shore Neutral-earth bond often relay-switched only when required Very common in blue-water boats running solar + battery systems Key idea (important for safety & corrosion) Protection is provided by RCDs, isolation transformers, and proper bonding strategy not by tying everything to the hull This is exactly why many marine standards (ISO 13297, ABYC E-11) allow or prefer floating AC systems.

Select to expand quote

cammd said..
Option 3 - engage an electrician to do the install

I am not sparky but I know enough to realise often bad wiring isn't discovered until a fault occurs. That is when it becomes a disaster, get it wrong and you could be planting a time bomb.

Most of the Sparkys I have met have no idea about this complex stuff. The last one I dealt with didn't understand why the fuse needed to be at the battery end of a power cable not the load end.

There is still only option 1 or 2. Sparky or no Sparky.

My contribution (I have just completed a lot of IEC60601 Medical Device Safety work). Feel free to correct me if anyone can explain better.

The original idea of an "Earth" was to "Earth" the metal case of an electric device. The idea being that if an electrical short circuit occurred between the Active wire inside (the dangerous one) the metal case the current would be safely diverted to Earth rather than the metal case being "Live" (connected to the active wire because of a fault) which might then hurt or kill a person who then touched that metal case while at the same time being connected to the real Earth causing the fault current to go through him.

Then double insulation came along. If the device doesn't have a metal case (ie power tools, TVs etc), then the Earth is redundant. Thats why many devices have two pin mains plugs.

In the case of a 240VAC inverter on a boat. I personally always bought 12V appliances. A bit of salt water around 240VAC and danger danger, way too scary for me. But if you did have one....

The Inverter will internally highly likely have small capacitors for noise suppression connected from its Active output pin to its Earth output pin. Also from its Neutral output pin to its Earth output pin. They conduct electrical noise from those pins to Earth. The more metal everywhere on the boat that is connected to this Earth pin will reduce the EMI from the Inverter (which hurts your VHF reception etc). So its a great idea to connect it to the the hull of a metal boat but ......

Those capacitors can fail and connect the Inverters Active output pin to its Earth output pin. This means any metal connected onto that Earth is now live. (Dangerous). So your toaster or VHF radio antenna cable might be a death trap. If you get connected between the metal of hull of the boat (easy in wet weather) and a damp connection to the inverters Neutral output pin you can be hurt or dead. You have added a big dangerous electrode to your boat.

Medical devices specify "Safety Capacitors" which are guaranteed not to fail in a short circuit condition. An inverter made in China may not have these.

If you dont connect the Inverter Earth output pin to anything (ie no hull connection) the Inverters entire wiring is kept isolated from all other boat wiring in theory you can only hurt yourself if you get connected between its Active Output pin of the inverter and its Neutral Output pin. Thats much harder to do than if the inverter is connected to the metal boat hull.

The two options I see:

1. Connect the Inverter Earth pin to the metal boat hull to reduce EMI. But now there is an electrical safety risk factor. It might also induce electrolysis. (Do it via a good RCD you can test). Only ever use double insulated appliances.

2. Don't connect the inverter Earth pin to anything. You may have higher EMI. Only ever use double insulated appliances.

I would go with option #2 if there was no EMI problem.

Others who understand this swamp please comment :-)

You are quite right. But many I emailed didn't reply. I'll check up on that one!

Quite right its virtually impossible to shield a magnetic field. There a metal alloy called Mu metal that re-directs a magnetic field through itself so when placed appropriately it acts like a shield. But its heavy and expensive.

I know two people who were on sailing boats that had masts hit by lightning. From what happened to them, and my experience with the nasty effects of high voltage arcs there are three protection methods. These apply if you find yourself on a boat vulnerable to lightning. 1. Sit far away from the mast at an extreme end of the boat. 2. Wear sunnies. 3. Plug your ears with toilet paper (if nothing else). Both people I know were burnt and got eye and severe hearing damage.

Recently as every year I went through the pain of Googling etc getting boat insurance quotes and compiled a big list of insurers. There are a lot more than I thought. Quotes varied for my Martzcraft from $900 - $2300. Astonishing for the same boat in the same place. Anyway I compiled a list and posted it on the net (with a shameless commercial at the end which I hope I dont get booted for ).
Any else of us needing and insurance quote this will make it easier.

www.boatinsure.au

I would love to install one of these, I have the space for it. But $4K is way to expensive for me.

www.boatgearaustralia.com.au/isotherm-itc-diy-fridge-freezer-kit-200-65l-ss-ut?srsltid=AfmBOoqxa2YYoKHuRjgGfPupGFHv5gOzgMIdfxm1GiDSFLfFttZQBYIE

Ive been using a Waeco for the last 5 years, it works perfectly. I turn it on and off remotely from home using my Trek Transponder by SMS. Usually leave it off to save batteries and its wear and tear and turn it on the night before heading to boat. Trek Transponders have a new 50A relay that you can use to remote anything which I use for the fridge even though its only 6A (10A surge at turn on).. Ive got a second one remoting the deck lights in case a crim gets on board. I monitor the fridge temperature remotely as well to make sure fridge is working. The Weaco takes about 4 hours to cool to beer drinking temperature below 4 Deg C and is half half fridge freezer. Perfect! Relay below - IP67.