You can use whatever colour you want, even use the same colour for everything, as long as the wires are identified and you keep a record of what is what.
Yes, of course use proper cable, but there is no "electrical code" to follow.
Not working properly is nothing to do with the colour of the sheathing of the wire, or probably nothing to do with the type either. They are either wrongly wired or have poor connections (or both). Most common for 12v wiring such as this to use red and black tinned wire of a size appropriate to the load.
Hi Tranona many thanks for the msg and you are probably right, but the only thing is the wiring is 3 core not 2 core so I wouldn't be able to use the black and red wiring. The person who installed the wiring has one colour wiring going into another one then connected which I can't understand why. I will install one wire straight into the connection rather than 2 that's why I asked what colour as I'm not an electrician. There are 2 switches and both have 4 different types of wire.
This 12voltplanet.co.uk/oceanflex-stranded-multi-core-tinned-copper-cable.html is the Oceanflex tinned multicore cable. As you can see 3 core is red black and green. Normally one would use the red and black for +ve and -ve the green for whatever else is being connected.
As you have several wires to replace, i would not use 2 core flex, i would use single wires, or it gets very bulky/clumsy. You can use whatever colours you want, but it would be good practice to use black for negatives and red for positives. Just label them accordingly.
Sorry, but i don't think this is an appropriate cable for the OPs job. It's 1.5mm, which is way, way over spec for simple engine instruments, 0.5mm would be more than enough in terms of current carrying capacity, but for the sake of robustness 1mm would be best suited. 3 core flex, in this instance, is unnecessarily bulky, particularly because the OP needs 4 cores, so single wires would be more appropriate. Finally, at nearly £3 per meter it is unnecessarily expensive, 12v Planet single cored, un-tinned cable is a mere 54p per metre, or 40p per metre if a 30 metre roll is purchased. The OPs boat will have been built with un-tinned wire (as almost every was was/still is) and the flybridge helm is a dry and sheltered location.
What do the switches do ? Can you take a picture of one of the switches, from the front and rear ?
I was responding to the question about colours of 3 core - not the choice of wire size.
This would be absolutely the wrong cable to use.
Hi I have been told that I can use any colour wire. On the boat at the moment is 3 core orange cable with blue, brown, yellow and green connected to other colour wires then put onto the switches. On the other side white colour cabel with same colour wires then connected to other colour wires onto the switches. On the switches are also X2 2 core with blue and brown then connected to dial wire and then onto the switches this is the same on both sides. I want to put a 3 core wire straight onto the switch then new 2 core cable connecting the dial wire then onto the switch so please can you advise what 3 core wire to use and 2 core wire.
Read posts #10 and #11
It's not 5 core it would be 7 core. There are 3 wires at the moment X1 3 core and X2 2 core.
Hi Paul sorry your right and I wasn't thinking. So I think that the single brown and single blue be a better option.