Shore power kits

[Trevethan]

Does anyone recommend the Seamark Nunn shorepower kit (£80)? Any suggestions for alternative suppliers. Woukld it be better going to my local electrical shop and getting the bits and pieces, and if so, what pieces!

I am looking for a basic set up - Say 6 soclets around the boat, plus one more for the battery charger and a connection for the calorfier's immersion.

From this I reckon I need an external female socket running to a consumer unit.

In the consumer unit I think I'll need a residual current thingy.

From there, mini circuit breakers. Should I do one ring main for all 6 domestic sockets.

I guess I should have a standalone circuit for the charger, and another standalone for the 1 kw immersion?

Is this sensible?

Also, I'll be fitting an invertor at some point. I guess this should also be wired into the consumer unit with a make after break type switch to select either the shorepower or the invertor and never both.

All advice, as usual, gratefully received

regards,

Nick

 

[bryantee]

have a look at towsure web site.marine sect,

 

[jfkal]

What is the sites full URL?

 

[rogerm]

You might like to look in a caravan dealers for a mains hookup kit which might be a bit cheaper.
Otherwise you are right. Just make sure the consumer unit is a plastic type (so that it doesn't go rusty) and try and find a residual circuit breaker with a rated trip current of 10ma (the norm is 30ma) to be a bit safer.

Of course the switchover for the invertor makes it a bit more complicated as the switch needs to go between the blue incoming socket and the consumer unit but you still need a circuit breaker between the blue socket and the switch.
Roger

 

[johmal]

Once you make extensive use of mains power on a boat you need to make sure everything in the boat is properly earthed. The sort of unit you are considering will also probably result in the low voltage -ve being linked to earth. Under these circumstances you will need a Galvanic Isolator, because mains earth might be different to local earth potential. This can result in accelerated corrosion, or your zinc anode dissappearing at an accelerated rate.

For more info - search on Galvanic Isolator - and you should pick up a good thred back in June this year. There were some other good threads on shore power around then.

John M.

 

[Trevethan]

Tried teh caravan dealerships. Their units have a 10 amp capacity and only have one circuitbreaker.

I want a system where I can switch off the ring main, the battery charger and immersion independantly. So juyst spent £50 at local electricians for consumer unit rcb, three circuit breakers and some armoured cable. Caravan guys said their skin fittings were not really suitable anyway so will be off round trhe chandelry for that later too.

Thanks for help so far!

 

[Trevethan]

Spent the weekend playing with teh electrics, in between fishing storm blown stuff out of the canal basin. Upshot is we now have one twin socket wired via a proper household consumer uning complete with RCD and three cb's. Made up a nice new shore cable too.

Much easier than having a reel of cable dropped in through a hatch and the additional safety is a big plus.

Thanks for the advice. Next weekend will join up the 12 volt and shore power earths and fit a galvanic isolator for when the battery charger is fitted and we leave the cable connect for longer than an hour or two.

regards,

Nick

p.s electrician is coming (at swmbo insistance) to check it all out. But the meter shows its ok.. (247 volts) and the unit trip when the button is pressed.)

 

[yachtbits]

I hope this isn\'t too late

I assume that the circuit breakers you have are all double pole?

It is essential to isolate both live and neutral. This is more important if visiting foreign ports where neutral may not be as close to earth as in the UK.

kev


<A target="_blank" HREF=http://www.yachtbits.co.uk>http://www.yachtbits.co.uk</A>
sales@yachtbits.co.uk
marine electrics & electronics

 

[paulplatts]

It would be a good idea to fit a mains tester permanently in circuit - I got mine from Maplins - only a few pounds - but they are available from many sources. I found that, in half of the continental marinas I visited this summer, the live & neutral were reversed - though I have not found this to be a problem in the UK. So I also make up a short lead to reverse live & neutral when required.

 

[Gunfleet]

Re: I hope this isn\'t too late

<<This is more important if visiting foreign ports where neutral may not be as close to earth as in the UK.>>
What does this mean, Kev?

 

[tome]

Big Bang theory...

The neutral is actually earth at the power station, but by the time it gets to your house or boat it's crept up to maybe 6 Volts. That's why you have a separate earth for safety. If you re-connected the neutral back to earth, then a lot of current would start to flow from the neutral conductor down to earth (6 Volts divided by bugger all ohms is a lot of Amps). Even so, you wouldn't expect to get a belt from the neutral conductor because it's maintained within safe limits in the UK.

This has the advantage that only 1 wire (Live) is dangerous and equipment can be designed to take advantage of this for safety. The extra earth wire at the consumer end is connected to any metal bits on an appliance and designed to short the live wire (and blow the fuse) if it comes adrift. This means that the case which you're touching can't become live and flow through your ground tackle to earth.

That's why it's dangerous to swap the live and neutral and important that you check the supply polarity, especially in dodgy places. I use a cheap 13 amp plug device with 3 neons bought from B&Q which shows me that everything's ok.

If the neutral is not as close to earth as in the UK then it may eventually reach a dangerous voltage, which is almost as bad as reversing the polarity. Using double insulated appliances is a good way round all this, but not always possible (battery chargers etc).

 

[Gunfleet]

Re: Big Bang theory...

I use one of those B&Q testers too, Tome, I just never knew the underlying theory!