Electrics up the mast

[1340fxd]

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

[Nigel Birch]

you don't have earth on a 12v system just +, -

[1340fxd]

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

[Nigel Birch]

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....

[Fulmar433]

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.

[Fulmar433]

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.

[Nigel Birch]

I stand corrected!