Mystery cables

[mick]

I am currently! having a good look at my engine wiring (Bukh 10hp in Sadler 26). There are two cables coming from somewhere in the engine space and attached by a small screw to the flange of the raw water seacock. I say 'somewhere' because the ends in the engine space are unattached, presumably having parted company with their terminals. One of the cables is about 1.5 mm2, the other about 2.5, and I asssume they are something to do with earthing. Any comments would be appreciated.

 

[KREW2]

hi
Could they be for sacrificial anodes

 

[alahol2]

They are almost certainly part of the bonding to the external sacrificial anode. They should be attached directly to the anode or to it via the engine or via another seacock.

 

[bluedragon]

I've got two wires running up to (but not attached to) the seacock on the sea toilet. Like yours, they must be for galvanic protection, but why aren't they connected?? I've read that some people won't bond their through-hull fittings in case of a lightning strike...maybe that's why? Any thoughts anybody?

 

[alahol2]

Lightning strike while sitting on the Loo?! Doesn't bear thinking about.

 

[oldharry]

There is nothing in the official circuit diagrams like this, so they must be part of an earth bonding system which ensures that there is not a galvanic cell set up between the engine and the seacock. Not obvious why 2 wires though?

 

[bluedragon]

Reading Nigel Calder's book last night, there is a school of thought that says don't bond electrically isolated skin fittings if made of brass or bronze. They don't really need protection and eat up the anode which should be protecting the engine, etc. I must ask the previous owner of my boat if that's why my seacock wires are disconnected. Re. the previous post, I guess two wires are part of a ring system of grounding ie. wire no.2 goes to the next fitting?

 

[oldharry]

[ QUOTE ]
, I guess two wires are part of a ring system of grounding ie. wire no.2 goes to the next fitting?

[/ QUOTE ]

Sounds reasonable.