Put quite a lot of feelers out to see if the wiring colour coding on Trudy-Ann was acceptable. Well, I’ve had it confirmed by British Marine Electrics Association that the wiring does not comply with regulations. At this stage all I have done is to order an interactive copy of BMEA codes of practice from the British Marine Federation but it certainly looks like I am going to have to rip out all of it and replace the 12V wiring throughout the boat, possibly rerunning the 240v circuits as it is all bunched up together.
As I understand it, 12V wiring should have a black negative though it seems there can be variations to the positive, the norm is to have red as the positive at least as far as the controlling switch and then the appropriate colour code to the lamp / motor etc. may be used (but no colours used in the 240V system) with a black return wire. If I have got this information round my neck feel free to correct me. Also the 240V system should be kept separate from the 12V. None of this is happening as you can see from the picture.
I asked the question during the build and was told this was the wiring code that applied. This has now been shown to be incorrect but it means that he has probably wired other boats to this standard.