Confusing earth wiring

When buying Vida, our surveyor included concerns about the earth.

We knew that the engine was “earthed” by a jump lead to the stern tube (and the jump lead was very rusty).

I’ve just found these wires connected to the anode that is bolted through the hull.

Quite a collection! We have green/yellow, back, blue and red!

Hardly surprising that the earth wasn’t working!


4 thoughts on “Confusing earth wiring

  1. Jocko May 31, 2021 / 9:16 pm

    I hope you got yourself a discount from the Surveyor.

    He should have been only concerned with the condition of your vessel, and not whinging about climate change.

    When addressing the rats nest of wiring, I expect that you will upgrade to Flat Braid Copper ribbon as Grounding straps throughout the vessel.

    The Braid, and appropriate terminals, provide heavy ground which can better withstand corrosion, and being knocked about in the bilges and lockers than can those thin plastic coated wires I see in the photos.

    Now is the time to consider upgrading your wiring, and grouding system with an eye towards Lightening, and Electrolysis mitigation, practical placement, and maybe even anesthetics.

    At the very least run two flat braid grounding straps from the metal Mast, down as straight a path as you can manage to a metal grounding plate affixed to the outside of the hull under the mast.

    For the sake of the next caretaker of the vessel please be decent enough to clearly Label the neat and tidy wiring as you go, so they won’t be cursing you, as you are no doubt cursing the previous slapdash electrical wizards.


    • dave42w May 31, 2021 / 11:02 pm

      We did get a good thorough report from the surveyor, definitely felt worthwhile.
      We have the standard Nigel Calder book and a son who is an electrician guiding us. Now that we have only 2 seacocks (and they are composite) life is easier for earthing.
      We are also fitting an isolation transformer so we should have good protection from mains supply issues.
      Lightning protection is tricky. A deck stepped mast with the mast support post resting on the encapsulated lead keel. So a straight down electrical flow to an external plate is difficult.
      Yes we agree about labelling and tidy wiring. We are going to be able to fit generous conduits which should simplify things (separate for DC and AC).


    • Jocko June 1, 2021 / 5:14 pm

      I hope others comment on this topic as well with their wild and wacky solutions. I want to learn how others deal with the lightening menace, other than just ignore it and hope it never hits home.

      Most boats do not take a direct Lightening strike on the Mast, and some actually stay afloat after being hit, but occasionally, if there is no easy path from the Mast to the water, the lightening will blast a hole through your Hull, and your boat will go down. Most likely you would just lose most of your electronic equipment though, if that is any consolation.

      Lightening is unpredictable and one never knows just how it is going to go.

      Since you are mucking about with rebuilding your Grounding system, I am hoping you will study up on what you can do to lessen your boats attraction to Lightening, and increase the likelihood of survivability.

      You are a Maker, and a Git er done kind of guy so the solution to your deck stepped Mast, and keel configuration posing a problem for you will soon fall to your ingenuity.

      I have a few janky ideas that may work, or Not, but you need your own better solutions.

      You do the hard thinking, and the engineering. I will just copy your solution if i find myself in your situation.

      Thats why I keep coming back here Davey Boy. Because you are the Boss


      • dave42w June 1, 2021 / 8:25 pm

        Lightning is such a small problem in the UK that our experience and knowledge is generally minimal.
        I’ve seen the effects of both Sailing Soulianis and Parley Revival getting hit. Of Sailing Magic Carpet and Sailing Fair Isle in lightning storms we never see here. I’ve found some quite unbelievable websites making wild claims.
        I’ve not seen anything like a consensus about either the risk or what works.
        Then you add in that we are outside the parameters of research or published stories and it becomes very messy (ketch, dyneema rigging, deck stepped mast, encapsulated keel).
        My main thoughts are.
        a) any “safe” route for lightning is going to have to be massive gauge, a very straight line and good electrical connections or the lightning will jump to make its own connections.
        b) a key priority is what electrical stuff can be protected. Double disconnect of motor and batteries? Wireless wind sensor on the mast? Fully prepared backup navigation system (tablet?) wrapped in layers of plastic and tin foil, including battery and portable solar panel? Spare aerials with cables for pushpit mounting?

        I’ve also wondered about ways to bodge a route that would handle some, even many situations (to be honest I suspect there will be some potential hits that are impossible to fully protect from). For example heavy gauge wire looped around the mast multiple times and hanging over the side. Seen that as a suggestion for catamarans to hang between the hulls several times.


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