Q1 - Replacing wire to anode?

Richard10002

Richard10002

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Decided to replace some of the wires which end up at the anode.

The first one connects the anode to the engine side of the stern gland, and the second one connects the stern gland to the gear box.

Does it matter what thickness of wire I use... the one I propose to use is about half the diameter of the one it's replacing, (I think it's the blue cable out of a piece of mains 3 core wire, and it seems to be thicker than some 8A rated wire that I have).

I'm guessing that the currents which might flow down this wire wont be very high... but I'm no expert.

ALSO:

There is a second connector on the stern gland bolt but the wire has broken off it, and I cant see a loose wire anywhere in the vicinity... so I have one wire connecting the gland to the gearbox. Any idea where a second wire might have lead to... or could whoever did the previous replacement have been lazy and just snipped the wire without removing the connector.

Hope that all makes sense

many Thanks

Richard
 
Cant see any evidence of a brush, or where one might have been and, if I'm understanding this correctly, the prop shaft has its' own anode, so shouldnt need a connection to the main anode... or am I misunderstanding something?Each time I look, I'm thinking it is a leftover from the previous change.
 
Stern tube needs to be earthed to a point, I say point, some say it should be the engine/gear box and others say the anode (Main), when I was employed as a marine electrician we always earthed to the anode first ,thence to the engine. the conductor size was a mininum of 2.5 sq. Shafts, if the customer wished had brushes fitted as well, and any coupling linked from shaft to engine side as well, all these extra bits aid the flow of electrons to one point, many engine and gear box bearing life has been shortened by not taking these measures. especially white metal bearings.
 
Thanks for that....How can you tell if a wire is 2sq, (mm I presume)? I know the wire I'm using is thicker than a wire which is rated to 8A for a run of about 2m, but it is thinner than the wire I'm replacing.

If I need the thicker wire, I can get some tomorrow.

I cant pretend to know what is connected to the engine or the anode, and am trusting those who have gone before to have it set up correctly, (for the time being), although I know you cant count your chickens.

One bolt coming out of the anode has 4 wires dissapearing under the aft bunk to, I dont know where. The other bolt has one wire connected to the stern gland, The stern gland is then connected to the gearbox, and these are the ones I plan to deal with for the time being.

I cant get my head around this protection thing...... do we earth things to the engine block, (e.g. AC earths), then from the engine to the anode... which is possibly how part of this system is arranged.... or do we earth to the anode, which is connected to the engine anyway, which may also be how this system is set up.

I'll get there one day

Richard
 
The core diameter of 2.5mm² 50/0.25 flexible cable is approx 2.2 mm. It is rated at 30 amps but I do not understand why wire that heavy is required.

You are using proper tinned (marine) cable aren't you. Remember that all connections must have a low resistance so good quality terminations securely fitted are essential. Personally I'd solder them on but others will object. I suggest a coating of vaseline over the connections once made to guard against corrosion will not go amiss.
 
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