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Posted by on Jan 13, 2013 in Boat Maintenance, How To, Marine Electronics, Powerboating, Sailing, UK, US |

Does Copper Need Coating in the Marine Environment?

Copper bus bars can take on a patina without losing any of their conductivity, but there's no harm in protecting them further.

Question: I just took delivery of my new boat last week and now that I’ve had a chance to dig around behind panels and inside lockers, I have a question about the solid copper bus bars used on the boat’s electrical distribution panels. I sent in a photo of the actual installation so you can see what I’m talking about.

Copper Bus Bar

A copper bus bar like this one in a protected interior space shouldn't need covering, but a spray coat of Boeshield T-9 never hurts.

Is there anything I can do to keep these bus bars from getting corroded in the marine environment? I live in the Southern US on the Gulf of Mexico and from what I’ve seen any uncoated metal near the water here corrodes pretty rapidly. This can’t be good for my boat’s electrical system.

Answer: Your bus bars are a bit unusual. Most builders today would use the solid copper bars, but they would be supplied with a tin coating on them. The tin does a very good job of keeping corrosion at bay. It appears from the photo that your bus bars are located in a cabin on your boat and in an area where direct exposure to spray or high moisture levels is not too likely. That said, the bars would only develop a brownish colored patina over time that would have no impact on your new boat’s electrical system performance.

But, if bright pink copper is your thing, I highly recommend a product that is available at most good marine supply houses — Boeshield T-9 spray. I’ve been using it for years on battery terminals, bus bars,  and electrical terminals that live under consoles in much more exposed environments than yours. The Boeshield sprays on a nearly clear coating that hermetically seals the terminals and bus bar surface. No exposure to moisture equates to zero corrosion.

I prefer this to the liquid electrical tape that some folks (and boat builders) use because it is clear, and in the event that the coating gets violated and some corrosion does eventually develop, I can see it. The liquid electrical tape creates an opaque coating, and I’ve had more than one case where the corrosion has built up under the coating and gone unnoticed for some time, getting to the point where the corrosion build-up caused an electrical failure.

- Ed Sherman