Boat Electrics Im Confused

[BayC]

Hello everyone. Having enjoyed the Broads for many years I have purchased my first Boat so please go easy on me. I have a question about boat electrics. The previous owners have done all sorts of electrical works to the boat, so is no longer stock, but I cannot quite figure out what Is going on. The boat has two batteries. Is one for engine start up? and the second for powering lights and sockets etc? at 12V?

Firstly, it has had a shore power socket installed on the back of the boat which I assume feeds power straight to the sockets installed onboard? So the sockets will now be 240V? and I can plug various items in. When I look inside the cabin I find the following fuse box (see Zig pic ). The question is: I assume for the house battery (or whatever it is called) will not be charged directly from the on shore hook up, there may be a battery charger installed somewhere so the shore power will recharge the battery? If this is the case why would the fuse be turned off? How can I find out?

 

My second question is why would you install this? (See fuse box pic) Although when I inspected it no wires are plugged in?

Thank you in advance for any help

 

 

[grendel]

the zig unit looks like standard caravan electrics, a commercial panel 

the second unit looks like a standard 240V setup with circuit breakers, maybe a started but not completed job, 

if you are not an electrician, it might be worth getting a marine electrician in to check it over and tell you what you have got, remember if that panel is plugged into 240V, then its as dangerous as your house wring.

whether your house battery and engine battery are charged from the shore power will very much be determined by the charger installed, some can be configured to independently charge both sets of batteries, but once again a marine electrician can tell you that.

As an electrical designer, I know enough to decide what not to touch, and what I can work through, the big problem will be if an amateur has got their hands on it and everything is a squirrels nest of wires, all the same colour as that is what they had available.

[Cheesey69]

What I done is get a stand alone charger that that charges the house battery and starter. 
plugs into its own 240 volt socket via plug. 
simple to understand and protected by a fused plug and distribution board. 

[BayC]

2 hours ago, BayC said:

 sorry picture quotes wrong way round. Fuse box is installed. zig is not wired up yet.

 

[BrundallNavy]

You can check if the charger works but using a meter to check the battery voltage if it goes up when you plug shore power in it’s working. 
Any 13 amp 3 pin sockets will only be 240v they must never be wired to both 12v and 40v at the same time. 

[floydraser]

You are not alone; most boats get their electrics "modified" by owners of varying levels of competence and eventually someone down the line has to sort it all out.

You probably should have one battery for the engine as you say, and a Leisure battery for the domestics. I understand they have different characteristics with regard to charging and discharging rates.

The "fuse" is actually a circuit breaker and while it could be turned off it may have been tripped by an electrical fault in the circuit or the charger.

The second panel (bottom pic) is purely for the 12v system. When you are out cruising and unplugged from the 240v this is what you would be relying on; it does contain fuses.

Well done for asking the questions and posting the pics but I strongly recommend you get a specialist marine electrician to cast an eye over it and explain the system clearly to you.

[Vaughan]

The ZIG panel is also for 240v shore power, as it has a switch labelled mains and 13amp fuses for the fridge when on mains power.  These are themselves out of date and should be circuit breakers instead.  You may not know, but volt drop in a circuit can overheat and start a fire, without blowing the fuse.

If this is not wired up yet then you really ought to give the job to a qualified marine electrician.  There are regulations about shore power circuits on boats and especially, they have to be properly and carefully earthed. Basically, mains electricity and water do not mix.

Please don't try and do a DIY job on this or I can assure you that you will only regret it later.

By the way, I suggest John Spruce. He is the best one I know.

 

Edited August 31, 2021 by Vaughan
line added

[Oddfellow]

Whilst I hold a British Marine Electrical Technician certificate, I no longer work in this environment so can advice only. 

DO NOT PUT THE ZIG UNIT IN YOUR BOAT. PUT IT ON EBAY AND GET RID OF IT. 

It's not designed in any way, shape or form for a marine environment and any marine electrician that installs it for you should be avoided. It's old, outdated and is designed for a caravan or motorhome which is very different from a boat. Also, the charger in it is awful and will not prolong the life of Deep Cycle batteries which is what should be used as your "house" batteries. In boat terms, we'd call these Domestic.  

A bad 240v installation might use the circuit breaker as the on-off switch for the charger. Just a thought. You can tell a bad 240v installation from a number of things and the instant giveaway is the use of solid twin and earth cable that you would find in a land-based installation. Multicore Flex must be used in boats as the vibration can snap the single cores with devastating consequences. 

You need to investigate more or get someone else to do it. John Spruce is very well respected in these parts but also very busy because of it. 


 

[grendel]

the zig is the older technology, so may have already been unwired to allow for the circuit breakers.

[annv]

Suggest you get someone to draw up a wiring diagram, simple enough, normal practice is to have a battery charger for the domestic battery(house battery) all 12volt items should run from this via fuses(mcb's) the engine battery(starter) should only power engine electric's ie starter, wiper this is charged via a battery maintainer when on shore power, when sailing from engine alternator, the domestic battery is charged via a relay/diode/advanced charger when sailing from engine alternator, the two battery banks should each have a battery isolator switch which should be switched off when you leave the boat, many of these items my be basic which require human intervention or more upmarket and work completely automatically, have you not spoken to the previses owner? have you plugged the shore power in(what happens) have you started the engine up (what happens?. did you get a survay? has no body told you anything about the boat? you need to know about the boat for your own safty and others. John

[BayC]

Thank you everyone for your advice, some of what i have now makes a little more sense. I will remove the zig, as its not wired inn anyway. Just got to find something that will fill the large hole left in my cabinet side.

I will have an marine electrion inspect the 240v system and circuit breakers and also try and see if i have a battery charger already installed.

Thanks again

[BayC]

54 minutes ago, annv said:

Suggest you get someone to draw up a wiring diagram, simple enough, normal practice is to have a battery charger for the domestic battery(house battery) all 12volt items should run from this via fuses(mcb's) the engine battery(starter) should only power engine electric's ie starter, wiper this is charged via a battery maintainer when on shore power, when sailing from engine alternator, the domestic battery is charged via a relay/diode/advanced charger when sailing from engine alternator, the two battery banks should each have a battery isolator switch which should be switched off when you leave the boat, many of these items my be basic which require human intervention or more upmarket and work completely automatically, have you not spoken to the previses owner? have you plugged the shore power in(what happens) have you started the engine up (what happens?. did you get a survay? has no body told you anything about the boat? you need to know about the boat for your own safty and others. John

Hi. Thanks for the helpfull info. I bought the boat from a broker so did not speak to the previous owner. I plugged in the shore power but did not plug in anything into the sockets so dont know if anything worked. I have not started the engine up with the shore power attached? i had a survey but nothing mentioned in the report yet. So unfortunatly having to try and learn everything myself. As i said my main concern was why the circuit breaker was in the off position with a label above saying battery charger. i have noticed a sign poiting saying battery isolator switch so could you explain why i need to turn this off when i leave the boat.

Thanks again

[grendel]

it will ensure nothing is left on to drain the batteries while you are not there, the important things such as bilge pumps should be wired into the batteries direct, bypassing the isolator, but if for example you left the fridge switched on, you could find dead batteries and expensive replacement necessary.

[annv]

Hi Bay c I would think that you have or had a basic battery charger that needs switching when not being use by the mcb this is not good practice! but better than nothing, perhaps if you ask the broker to pass your phone no to previous owner you my get some info about your set up, what boat do you have? If you intend to use it for long periods off your mooring/shore power you will want to upgrade your system for something better, the purpose of a battery isolating switch is to switch/isolate the battery to stop it discharging/going flat if ang thing is still switched on/connected, you can get a feed back through alternator, BUT as Grendel said the bilge pump should still be wired via a fuse and still remain connected to the power, if you would like some practical ideas on what you can have, contact me. John

[floydraser]

10 hours ago, BayC said:

Hi. Thanks for the helpfull info. I bought the boat from a broker so did not speak to the previous owner. I plugged in the shore power but did not plug in anything into the sockets so dont know if anything worked. I have not started the engine up with the shore power attached? i had a survey but nothing mentioned in the report yet. So unfortunatly having to try and learn everything myself. As i said my main concern was why the circuit breaker was in the off position with a label above saying battery charger. i have noticed a sign poiting saying battery isolator switch so could you explain why i need to turn this off when i leave the boat.

Thanks again

I'm confused by this, but then confusion is in this thread's title. 

Wouldn't safety be a big part of the survey, which in turn would cover these electrics? 

[annv]

Hi Floyd there are different surveys lots only want a hull survay some want a full survay along with engine survay, insurance company's often only need a hull survay the cheapest, and if sold by a boat yard the owner dosn't need to be there that's why you pay a commission to boat yard or boat shed to show the boat, give a trial run and organize a survey lift, and collect the money on be half of seller who can live many miles away. John

[floydraser]

46 minutes ago, annv said:

Hi Floyd there are different surveys lots only want a hull survay some want a full survay along with engine survay, insurance company's often only need a hull survay the cheapest, and if sold by a boat yard the owner dosn't need to be there that's why you pay a commission to boat yard or boat shed to show the boat, give a trial run and organize a survey lift, and collect the money on be half of seller who can live many miles away. John

Yes but in this case the OP writes, "i had a survey but nothing mentioned in the report yet", suggests to me that he paid for a full survey and expects a full report.

[annv]

Hi Floyd they often will phone with a quick report ie dont touch it or nothing drastic with a itemized report by post later this enables you to buy or not to buy straight away, plus a survay? dosn't imply what type to me. John

[TheQ]

As for not putting that Zig unit in a boat, if it's a broads motor boat we are talking about, they're floating caravans anyway, many of the electrical fittings used in the hire ones are not marine rated, never have been, there just isn't any need. What's the difference between a boat on the river and a caravan sat on the bank by the river?

 That being said the Zig unit isn't a particularly good charger, there are many better around..

[floydraser]

3 hours ago, annv said:

Hi Floyd they often will phone with a quick report ie dont touch it or nothing drastic with a itemized report by post later this enables you to buy or not to buy straight away, plus a survay? dosn't imply what type to me. John

It seems to me though, that the OP seems to expect something in the survey report. If so, I reckon the state of these electrics would have been worth mentioning even in a phone call. Maybe there has been a misunderstanding between the OP and whoever organised the survey? 

As someone daft enough to buy a project boat without a survey, I deserve everything I get from it. However, it seems to me the OP may have done it properly, using prefessionals, and ended up in the same.... no, I can't.