Any clever people would like to help me rewire my boat?

[Malabarista]

Thanks Greg for your advice. I think if you look very hard you see Mr Calders stamp all over my work [emoji846]
I have been studying ( in solitude) from books and the internet but i am the kind of guy who doesn’t quite trust what i have learned from a book until i can see it put together. The penalty for getting this system wrong is at best a non functioning system and at worst a viking funeral scenario. I have noticed that many people are happy to advise on that which they have not read nor understood. This is i think human nature. It does mean many hours of checking that what has been advised is correct but this only improves my knowledge.
I was quoted £400 per day for a marine electrical engineer to do the work for me with no estimate of how long it could take even after he had been aboard and looked. I can understand why having already dipped my toe into the water. It is a melon twister for sure. A simple cable run can be diverted by other systems ( we already did the plumbing work) and this makes the cable longer which involves recalculating the voltage drop which may mean swapping either the circuit capacity or pulling the whole lot out and changing the wire gauge.
My wife likes lights…lots of lights…too many bloody lights.... but hey we need to keep her happy right?

[Malabarista]

Originally Posted by GrowleyMonster

You are using an ELCI shore power inlet breaker and an isolation transformer for connecting shore power, right? An isolation transformer is heavy and expensive, but adds tremendously to safety, especially for divers in the water. And most isolation transformers can be reconnected for different inputs and outputs, as long as they are rated for both 50hz and 60hz. Actually a 50Hz transformer is for all practical purposes rated for 60Hz. So if you sail into a marina with only 120VAC 60Hz shore power, you can in minutes be ready to connect to the local flavor of shore power, respecting your load and the shoreside equipment rating, of course. AC Motors would of course run faster but most stuff doesn't really care whether the freq is 50 or 60. And of course vice versa for those with 120VAC wired boats sailing into 240VAC countries. Mine which I am in the process of installing is a 3.6kw Charles, weighs about 80lb, and came to me slightly used for I think $400? Anyway the placard on the case is very clear about how to make connections for either 120 or 240 volt input and output, and is rated for 50hz, so I am good to go with a standard 30a US shorepower connection, or a 16a 240v 50hz foreign connection. I could set up a 240v circuit onboard but I don't need it presently so the connections are as specified for 120VAC output. The transformer is rated for 50Hz or 60Hz. Most 50Hz transformers will work fine with 60Hz, but a 60Hz rated transformer should not be used with 50Hz.



Another important thing. Your zincs (sacrificial anodes) are a very important part of your DC system. Neglect them at your peril.

Thanks Mr Monster [emoji846]
Some good stuff here. Unfortunately i have neither space or weight allowance for one of those babies ( as nice as it would be) so i am making do with a Galvanic Isolator which i have checked is functioning correctly after advice from a forumite.

[mitiempo]

Originally Posted by Malabarista

Thanks Mr Monster [emoji846]
Some good stuff here. Unfortunately i have neither space or weight allowance for one of those babies ( as nice as it would be) so i am making do with a Galvanic Isolator which i have checked is functioning correctly after advice from a forumite.

Skip the isolation transformer for a galvanic isolator. But do install an ELCI main breaker.

[Pete7]

Originally Posted by ozsailer

Gday Malabarista,
I have read a few of the replies here and while some are correct there are comments here that are just plain dangerous !!!!. Greg H
Lagoon 440

Really? please do highlight what you consider dangerous so others may learn from sharing information. Of course others may disagree with you, but that normally leads to a good discussion with different opinions and ideas.

Pete

[Malabarista]

Originally Posted by Cadence

Label both ends of every wire you run no matter what you decide on. And for God's sake bundle them neatly.

[emoji846]all in hand sir

[Malabarista]

Originally Posted by Malabarista

[emoji846]all in hand sir Attachment 206392

[moseriw]

Originally Posted by ozsailer

Gday Malabarista,
I have read a few of the replies here and while some are correct there are comments here that are just plain dangerous !!!!. Having repaired and replaced way to many boat systems undertaken by unqualified people I would be unease accepting advise from people on the net without knowing what qualifications they have. While I have seen some excellent work completed by others please be careful and double check information you receive. I would recomend this publication I think it would be of great assistance to you "Boatowners Mechanical and Electrical Manual
by Nigel Calder"



Greg H
Lagoon 440

AND NEVER TRUST A SO CALLED PROFESSIONAL!


I have seen a lot of "professional" repairs in the MED. All of the were a quick and dirty, often not marinized job for far to much money.


As boatowner you gotta know every bloody screw on your boat beeing able to repair it. Therefore learn, learn, learn, crosscheck everything you do 10 times or more before you do it and there is a good chance that you do it better than the "qualifieds"

[Reefmagnet]

I think I recall someone mentioned fusing as close as possible to the device being powered when the opposite is true. You should fuse as close to the power source as practical. Other than that I didn't read too much else that i personally thought was dubious.

Btw. Does everyone know Nigel Calder was actually a scientist? It surprised me when I found that out when reading his obituary a few years back.

Originally Posted by Pete7

Really? please do highlight what you consider dangerous so others may learn from sharing information. Of course others may disagree with you, but that normally leads to a good discussion with different opinions and ideas.

Pete

[ozsailer]

Pete7, I can see you point and agree but was reluctant to identify anything in particular but one thing stands out as just plain wrong. One poster stated
"I do not have a master fuse panel. I use individual ceramic cartridge fuses located in the positive leg of the power feed at or close to the apparatus, sometimes glued on to the back of said apparatus." This is so wrong on so many levels and the reasoning behind this decision just do not stand up. This does not meet any formal elecrtical standard in Australia and I doubt anywhere else. If the boat is insured and their was an elecrical fire I doubt any insurance company would pay out given the circumstances. Imagine selling this boat and a new owner trying to work out how the boat is wired or protected.
In regard to the original post, neither this member or anyone else has asked what the maximum current demand will be on the boat. How can you possibly identify what size cable you require if you do not know the current draw of the boat. This is just very basic electrics. I note that malabarista is utilising Nigel Calders very good books and I would hope he has completed these equations.


Greg H
Lagoon 440.

[Lake-Effect]

Originally Posted by Reefmagnet

Btw. Does everyone know Nigel Calder was actually a scientist? It surprised me when I found that out when reading his obituary a few years back.

Uh I think you're referring to another Nigel Calder. The marine technical one resides in Maine and seems to be still up and about. Another sighting.

[GrowleyMonster]

Originally Posted by Malabarista

Thanks Mr Monster [emoji846]
Some good stuff here. Unfortunately i have neither space or weight allowance for one of those babies ( as nice as it would be) so i am making do with a Galvanic Isolator which i have checked is functioning correctly after advice from a forumite.

Galvanic isolator is better than nothing. The transformer gives you greater flexibility though. Especially if it is tapped for different input and output voltages. Not so important if you don't need to use shore power when your "home" standard voltage is not available. Or if your AC power needs are met with your inverter. Anyway with a galvanic isolator you are still way ahead of the boats with no isolation at all, and there are still an awrful lot of them still around.



An ELCI breaker is lately becoming standard, for good reason. In fact I believe it is specified in current ABYC standards. You need an onboard shore power breaker, anyway. An ELCI breaker in an enclosure is a very important component in your shore power setup.