[Public-List] Shore Power location - AC & DC fuses; Charger

[John Birch]

Hi Don, et al

If I remember my Skenes or was it Calder, DC impressed magnetism can be 
cancelled out by twisting the wires, though it means somewhat longer wire is 
needed.

Brewer Brothers in Hamilton only sells tinned milspec wire, so I had no 
problems doing Sunstone to spec when I upgraded the AC and put in a 
Truecharge 40 smart multistage charger.

Remember, when putting in a charger that the Batteries should be fused near 
the positive terminal, I used 50 AMP Blueseas fuse blocks and bar fuses on 
each circuit between the charger and batteries. I also used bulkhead mounted 
Blueseas fuse blocks and a 150AMP bar fuse between the battery and DC 
switch, so the act of starting wouldn't blow the fuse to the DC switch. With 
450 house AMPs I figure any dead short would blow the 150.

Also added the Truecharge battery temp monitor which goes off the 450 House 
bank to the charger, so there is no risk of overheating the batteries. Seems 
quite effective at preventing boil out of the water. Only had to top 
batteries once this year, and it wasn't really necessary (rather 
precautionary), but did so after haul out so that the battery water level 
was at its exact proper height.

That way, I can charge the batteries over the winter aboard without worry.

Hope that is a help.

John


----- Original Message ----- 
From: "Don Campbell" <dk.campbell at sympatico.ca>
To: "Alberg 30 Public List -- open to all" <public-list at lists.alberg30.org>
Sent: Wednesday, November 23, 2011 9:23 PM
Subject: Re: [Public-List] Shore Power location


>I redid my shore power about 14 years ago to comply with a surveyors 
>statement that it did not comply with ABYS standards and so was dangerous. 
>I used the same place on the boat but it means that a 50' cord can be a 
>stretch if the shore power source is not really close. That said, I am 
>happy with where it is / was,  just starboard of the compass mount in the 
>bridgedeck. There was a requirement that the cord be fastened to the 
>fixture with a threaded ring. It helps if you use a GFI for the first 
>recepticle and go from there,  so all downstream fixtures are GFI 
>protected.
>     There is not much reason that an AC current ought to affect the 
> compass. First the wire ought to be copper and non-magnetic and then any 
> field of force arising from an AC current ought to be self cancelling. On 
> the other hand, if there is DC current in the area, then the current is 
> unidirectional and the ensuing  field of force may affect the compass 
> because it will be magnetic.
>     If there is any leakage from the AC current to the hull then you can 
> get accelerated galvanic action and zinc dissappears in a hurry. Even if 
> all you provide is a ground circuit, that is enough to cause major 
> troubles. Just be sure you isolate whatever you do so this does not 
> happen. The current leak may be in your neighbours wiring but finds its 
> way to your ground circuit and goes back to the ground  system on land 
> via either the white wire or the bare copper wire. Neither is what you 
> want. I would recommend Nigel Calder's book on wiring.  (It is also tough 
> to get AC wire that is tinned and in a bundle. If you can get just black 
> and white and green , then use that but not less than 14 gauge, preferably 
> 12 gauge if the cord you use is 12 gauge, and if it is a 30 amp cord , thn 
> it ought to be 12 gauge wire. There is no fuse or breaker for the short 
> stretch of wire that goes from the connector to the fuse panel and so that 
> ought to be able to carry 30 amps or whatever the normal shore power that 
> you are able to hook up to is without melting). Once at the breaker, then 
> you can go to whatever fuse or breaker you like and wire from there 
> accordingly. The main thing is to have any circuit protected to the usage 
> that you wire for and the current draw that is required for that circuit.
>     Enjoy the cockpit repair. I did that 14 years ago too and had to 
> re-glass the whole floor. Before the fix, if I stepped on the floor , it 
> would hit the gas tank!
> Don
>
> On 11/22/2011 9:26 PM, Ben Craig wrote:
>>                  I'm doing some cockpit repair this winter and was going 
>> to
>> update my shore power receptacle which currently is located in the 
>> cockpit
>> well just to starboard of the compass.  I would be interested to know if
>> anyone has had success with other locations.  It seems that its affecting 
>> my
>> compass deviation.
>>
>>
>>
>> Ben Craig
>>
>> Winsome #601
>>
>>
>>
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