Electrics up the mast

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1340fxd
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Electrics up the mast

Post by 1340fxd » Mon Feb 12, 2018 7:27 pm

I have two three pin plugs which run wiring up the mast. How are the lights earthed - is it the mast itself? Any mast wiring resources would be most welcome. Thanks

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Nigel Birch
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Re: Electrics up the mast

Post by Nigel Birch » Mon Feb 12, 2018 8:17 pm

you don't have earth on a 12v system just +, -
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Re: Electrics up the mast

Post by 1340fxd » Mon Feb 12, 2018 8:20 pm

Yes thank you and in that context is the negative taken to be the mast in order to reduce the number of wires run up it? Like a car where the body is the negative side of the wiring

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Re: Electrics up the mast

Post by Nigel Birch » Mon Feb 12, 2018 8:26 pm

No the negative always has it's own wire. Perhaps you could use the hull as the negative return on steel hull but even then I suspect it will have a dedicated wire....
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Re: Electrics up the mast

Post by Fulmar433 » Mon Feb 12, 2018 8:27 pm

It's normal to use one of the three cores as a common earth (-ve). My boat was wired with domestic 3 core 2.5mm flex up the mast. The mast head Tri Colour and anchor light is made with a common -ve and the a single wire to each of the two bulbs. I assume the steaming and deck light is a similar construction although I haven't had that apart.
Last edited by Fulmar433 on Mon Feb 12, 2018 8:48 pm, edited 1 time in total.
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Re: Electrics up the mast

Post by Fulmar433 » Mon Feb 12, 2018 8:45 pm

Nigel Birch wrote:
Mon Feb 12, 2018 8:17 pm
you don't have earth on a 12v system just +, -
It is quite normal to refer to the -ve in DC systems as Earth. As a former BT engineer we were trained that the 50v DC telephone exchanges were Battery (-ve) and earth (+ve). On the boat the engine, anodes and seacocks are all earthed to the -ve side of the battery.
Last edited by Fulmar433 on Tue Feb 13, 2018 8:34 am, edited 1 time in total.
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Re: Electrics up the mast

Post by Nigel Birch » Mon Feb 12, 2018 9:16 pm

I stand corrected!
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