What do you do when a wiring run suddenly changes color . . . or doesn't follow the convention used on the rest of your boat? Our simple and inexpensive solution.

Weird Wiring Colors

In general, Barefoot Gal‘s 12-volt wiring uses red for the positive and black for the negative. But as we’ve been doing work on various components of the electrical system, we’ve also come across white (both positive and negative), green, yellow, gray and even found one place where black was used on the positive side. On a few occasions, a single wiring run would change colors several times.

NOTE: All these colors do have particular meanings in a 12 volt system. Jamestown Distributors has a good list of color conventions. What I’m talking about is incorrect use of these colors.

Apparently, some people working on the boat had simply used whatever piece of wire they could lay their hands on that was the right size.  YIKES! It certainly has made tracing wires, well, interesting. Future troubleshooting might be even more problematic.

One option would have been to rewire the strangely colored circuits. But that would have been expensive and time-consuming. Plus, things worked well the way they were wired (one of Dave’s favorite sayings is “if it ain’t broke, don’t fix it”).

So we opted for the simpler — much simpler — solution: a few rolls of red and black electrical tape. Whenever we trace a circuit and find a funny color, we wrap the wire in the correct color (leaving the connectors un-taped so we can see any problems developing).

Straightening Out Wrong Wiring Colors: What do you do when a wiring run suddenly changes color . . . or doesn't follow the convention used on the rest of your boat? Our simple and inexpensive solution.

Straightening Out Wrong Wiring Colors: What do you do when a wiring run suddenly changes color . . . or doesn't follow the convention used on the rest of your boat? Our simple and inexpensive solution.We use a lot of cheap black electrical tape on the boat for non-electrical temporary things. But for this purpose, we bought “good” electrical color-coding tape, pictured at right.

While you can get it at West Marine and other specialty stores, it’s a lot cheaper to buy at home improvement stores such as Lowe’s and Home Depot. Here in the Florida Keys, it was almost exactly half the price at Home Depot as the exact same tape was at West Marine.

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  • Dave Skolnick
    Posted at 21 March 2015 Reply

    Note that new ABYC standards are for yellow 12VDC negative to avoid confusion between 12VDC negative and 117VAC hot.

  • Kit Russell Harrison
    Posted at 21 March 2015 Reply

    This might be useful in the camper’s wiring?

  • Court Crosby
    Posted at 21 March 2015 Reply

    It’s a lot quicker and easier to just wrap the correct color around the wire near each end.

  • Pete
    Posted at 21 March 2015 Reply

    It would a lot easier to tape each end but in bad lighting and or foul conditions it would be much easier to trace the line if it was the same colour. There are also wire identifying tags that are numbered and can be purchased online but I like keeping it simple and economical.

  • Chip Lawson
    Posted at 22 March 2015 Reply

    The only concern I would have with your tape solution is that after a while inexpensive electrical tape begins to deteriorate(can be within a year, particularly in a hot engine compartment) and you end up with a gooey, sticky mess and the tape will fall off and spread the goo elsewhere. A better solution might be to put longish sections of the correct color heat-shrink tubing at the ends of the wire at the crimp fitting and wherever there are splices or color changes. The heat shrink has a couple of benefits besides the color coding. It is nearly indestructible and will strengthen the wire-to-connector joint. And if you use adhesive lined heat shrink it will help protect the joint from corrosion and failure.

  • Ralph
    Posted at 24 March 2015 Reply

    I don’t know how this would hold up on a boat, but worth a test try would be: paint the wire in the correct color of finger nail polish (or even a stripe of enamel paint).

  • Susie
    Posted at 26 March 2015 Reply

    When our boat was made the builder took a no expense spared approach (they subsequently went bankrupt but that is another story) and labelled each end of every wire and pipe. It’s a practise that subsequent owners including ourselves have continued. Each and every wire is therefore easy to identify even if the wire itself is not necessarily the correct colour. It is perhaps time consuming to start from scratch but you could do this as and when so that eventually most wires would be labelled. Plastic tags last longer than sticky labels if you are sailing anywhere warm!

  • Louise Stanley
    Posted at 20 March 2016 Reply

    Always something interesting in your posts..and useful too.

  • Diana K Weigel
    Posted at 20 March 2016 Reply

    Just in time since we are trying to sort out the mess on out 30 year old boat!

  • Nessa Magee
    Posted at 21 March 2016 Reply

    Geoff Crowther not always as they seem ? Remember doing the light in cockpit ?

  • Pamela Harwood
    Posted at 22 March 2016 Reply

    As we are rewiring and replumbing the entire vessel, Hugh is using a fine black Sharpie on the wide white marine plastic covering of the red and yellow-coated wires to write what they are for. Battery cables, red and yellow, are big enough to write directly on them.

  • Meghan Thornton
    Posted at 04 August 2017 Reply

    Dealing with my heritage spaghetti wiring was what I did all day yesterday while nursing a sinus infection!

  • Dawn Read
    Posted at 04 August 2017 Reply

    Lucky, good idea until we hit the lottery and completely start over.

    Great article.

  • Gillian Lisa Johnston
    Posted at 04 August 2017 Reply

    This is one of the jobs to do while Moggie is out of the water! Previous owners have added wires, disconnected things leaving wires in place, left other items in place while just cutting wires. A fire hazard waiting to happen. I want to replace all the linings anyway as someone has installed lightweight melamine board as headliners. Easy to clean but now it’s breaking and coming off all over the place so a good time to trace the wires and renew.

  • Scott Doublisky
    Posted at 05 August 2017 Reply

    Coming from the industrial world where they used one color wire for every and all circuits.. we used wire markers.. a notebook full of numbered strips to mark runs. ie… The bow light circuit is #5.. Everywhere there’s a connection or junction in that run you put the #5 sticker all the way back to the panel..

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