Wiring for shore power

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richardh10

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I would be grateful if somebody could enlighten me as to how to incorporate a socket for shore power into my wiring circuit. At the moment I am just relying on the batteries, and as I may be spending some time in a marina over winter, I may as well make use of the electricity.
And while I'm at it how do you include some kind of dial to show the state of charge of the batteries?

Any advice welcome as I admit to being a bit of an electrical numpty!

Cheers
 
richardh10 said:
I would be grateful if somebody could enlighten me as to how to incorporate a socket for shore power into my wiring circuit. At the moment I am just relying on the batteries, and as I may be spending some time in a marina over winter, I may as well make use of the electricity.
And while I'm at it how do you include some kind of dial to show the state of charge of the batteries?

Any advice welcome as I admit to being a bit of an electrical numpty!

Cheers
Click to expand...
you cannot incorporate 12 & 240v together
the simplest way is just an extension lead with RCD protection.
the best way is a shore power socket into a "garage" type consumer unit that will give you 2 separate circuits / sockets.
42773.jpg

http://www.toolstation.com/shop/p42...r+unit&pmt=p&gclid=CMrQwaSS4rkCFeXMtAodkRUASA
 
If you have no AC power of any kind you will need a shore power inlet, a galvanic isolator (as you will be plugged in) consumer unit and a battery charger and whilst you are at it perhaps a few AC outlets for appliances and cheap heating. A proper battery monitor like the NASA BM1 or more upmarket Victron / Sterling et all models will cover energy monitoring. However you say you are an electrical numpty, in that case have a qualified person see to it, especially the AC as electricity hurts when it falls out of the cables on you. Possiblr from reading the scant info that you already have an inverter and AC outlets, if so it will be a bit easier
 
richardh10 said:
I would be grateful if somebody could enlighten me as to how to incorporate a socket for shore power into my wiring circuit. At the moment I am just relying on the batteries, and as I may be spending some time in a marina over winter, I may as well make use of the electricity.
And while I'm at it how do you include some kind of dial to show the state of charge of the batteries?

Any advice welcome as I admit to being a bit of an electrical numpty!

Cheers
Click to expand...

What shorepower arrangements do you have at the moment? At the very least you should have an RCD to protect you. An additional MCB or a combined RCBO is a very good idea. There are standards for these and I think on a new installation the RCD has to be within 1 metre of the inlet.

Do you have a charger for your batteries?

If you have nothing at the moment have you consiered just getting and extension cable with sockets and an RCD built in. Changing a mains plug to a shorepower plug like below is much less of a project and as long as you can tell you E from N & L should be low risk.

http://www.tcschandlery.co.uk/10236/GEWISS-Shorepower-Plug-16A.html
 
David2452 said:
If you have no AC power of any kind you will need a shore power inlet, a galvanic isolator (as you will be plugged in) consumer unit and a battery charger and whilst you are at it perhaps a few AC outlets for appliances and cheap heating.
Click to expand...

I have a double 13A socket with integral RCD and that's it. No need for galvanic isolation unless the 240V earth and 12V earth are connected. My previous boat lived in a marina for five years with a windable-uppable extension lead for mains power.
 
lpdsn said:
What shorepower arrangements do you have at the moment? At the very least you should have an RCD to protect you. An additional MCB or a combined RCBO is a very good idea. There are standards for these and I think on a new installation the RCD has to be within 1 metre of the inlet.

Do you have a charger for your batteries?


If you have nothing at the moment have you consiered just getting and extension cable with sockets and an RCD built in. Changing a mains plug to a shorepower plug like below is much less of a project and as long as you can tell you E from N & L should be low risk.

http://www.tcschandlery.co.uk/10236/GEWISS-Shorepower-Plug-16A.html
Click to expand...


At the moment I have no shore power arrangements, and the only charger for the batteries is the engine!

I think maybe the extension lead with sockets is the way to go, as most of the time I am on a mooring, but where is the RCD built in?

Cheers
 
richardh10 said:
I would be grateful if somebody could enlighten me as to how to incorporate a socket for shore power into my wiring circuit. At the moment I am just relying on the batteries, and as I may be spending some time in a marina over winter, I may as well make use of the electricity.
And while I'm at it how do you include some kind of dial to show the state of charge of the batteries?

Any advice welcome as I admit to being a bit of an electrical numpty

Cheers
Click to expand...

If you want to go down the route of a proper fixed shore power installation then a "garage consumer unit" as suggested by sailorman would make a good basis and cheaper than an almost identical "marine" unit.

It would be wise to get one with a waterproof rating of IP55 or better. The one in sailorman's link in post #2 is rated IP55
The correct inlet receptacle and connector would be necessary.

If the shorepower earth is bonded to your DC negative, anodes etc then unless used infrequently and never left plugged in a "galvanic isolator" is need to protect your anodes and other underwater bits and pieces from galvanic corrosion.

Installing a full shorepower system is not a job for a numpty however. You would be best advised to have it installed by a qualified electrician


If on the other had you only want something to use on an occasional basis there are several items on the camping and caravanning market which might be of interest for example

http://www.towsure.com/product/Camping_Site_Mains_Supply_Unit_3_Outlet

http://www.towsure.com/product/Pitch_Power_Mono_Camping_Site_Mains_Supply_Unit

These both include a circuit breaker and an RCD.

The simplest "dial" to show state of charge of the batteries would be a "battery condition" meter, essentially an extended scale voltmeter. Useful provided you are aware of its limitations. The alternative is to chuck a goodly sum of dosh at a battery monitor such as the Nasa BM1/BM2 or a "Smartgauge" which monitor the cahrging and discharging and pretend to be able tell you the precise state of charge of your battery.
 
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Proper bonding of the 240v earthing / ground to the 12v DC ground / negative is vital for electrical safety, especially for anyone in the water close to your boat and even more so if the boat is in fresh water. However, apart from a single link, these two systems have very different functions, so correct design is critical.

Unless you are simply occasionally plugging in the odd appliance, in which an RCD protected extension lead may suffice, then a proper and professionally installed and designed system is essential, IMHO of course, and generally as set out by various published experts on this subject.

If you use a car shop battery charger then there is a real risk of connecting the 12v system to the AC mains, as many if these are not full isolation units.
 
As said for occasional mains power use an extension cord either with RCD unit fitted or rely on RCD unit on jetty outlet. Electric cords are susceptible to damage etc so best only used when you are on the boat. You need to be mindful that if you turn on too many devices on mains power you could overload the system and pop the circuit breaker.
Devices that draw a lot of current are electric heaters kettles and toasters. Devices that draw little current are chargers for battery devices. Somewhat more is used by computers and battery charger for the ships batteries.
A temporary battery charger connected to the ships batteries should be OK provided you do not leave it on when you are away from the boat. ie OK for weekend use. a long term connection can result in electrolytic corrosion to underwater metal and requires a galvanic isolator.
Regarding a dial to indicate battery charge. I wish it were so simple. The total capcity of a battery can vary from new something like claimed capacity in Amp hours to less than half that when it still might be considered OK. Certainly a battery voltage falls dramatically when it is flat. So a volt meter can give you a warning of impending failure. Careful tracking of voltage may give an even better idea of charge state. So a volt meter is essential to check on battery condition and is fairly cheap. An amp meter is useful to check on actual charge going into the battery as this varies a lot depending on battery charge state. Generallyn lots of charge current when the batterry is flat and first start to charge tapering off to much less as battery is charged. An amp meter will tell y0ou when further engine running just to charge the battery is not very productive.
The battery monitor systems as suggested do purport to give a % charge figure for your batteries. This is based on in the case of Smart Guage voltage with lots of correcting algorythms
In the case of monitors like BM-1 they measure current into the battery when on charge and related to time and then current and time of discharge of the battery. These both are measured in amp hours. ie one amp for 1 hour is 1AH or 10 amps for 6 mins is 1 AH . Batteries are rated in AH as a measure of size although actual Amp hour performance depends on discharge rate and battery age.
So with a battery monitor you charge the battery up till you reckon it is fully charged. Then from a guess of battery capacity it can tell you the amount of discharge you have given the battery in amp hours therefor the % charge left in the battery. (aproximately) Certainly the charge and discharge quantities can be very useful in power management.
I think in the case of the OP a mains battery charger and perhaps a volt meter will enable power management for the weekend sleepover on boat in marina. Hopefully also the extension cord and a blower heater will keep you warm. good luck olewill
 
richardh10 said:
At the moment I have no shore power arrangements, and the only charger for the batteries is the engine!

I think maybe the extension lead with sockets is the way to go, as most of the time I am on a mooring, but where is the RCD built in?

Cheers
Click to expand...

There is no RCD buit in to the shore power plug in lpdsn's link. It is purely a plug to fit the pontoon supply outlet.

The pontoon supply should have an RCD but you don't know for sure if you can rely on it hence the requirement for an RCD, along with a circuit breaker, as part of your own installation. (The circuit breaker at least should be within 0.5m of the inlet unless certain conditions are met)

The links I gave earlier will provide you with a lead and one or three sockets protected by an MCB and RCD. Short of a full fixed installation this is the best option I am quite sure.

camping-site-mains-supply-unit-3-outlet.jpg
 
VicS said:
camping-site-mains-supply-unit-3-outlet.jpg
Click to expand...

That is what I have on my Centaur. I bought it from Go-Outdoors for £40, it's supposed to be for tent use I believe.
http://www.gooutdoors.co.uk/mobile-mains-kit-p155317

I was going to fit a caravan version £40
http://www.gooutdoors.co.uk/mains-consumer-unit-p155299

With a flush inlet socket £13:50
http://www.gooutdoors.co.uk/mains-flush-fit-inlet-square-p155305

and an extension cable £30
http://www.gooutdoors.co.uk/mains-lead-25m-p155388

plus a couple of fixed sockets for the fan heater, battery charger etc but the portable unit seems to be good enough for now.
 
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