Fuse size & wire gauge

[thataway]

[bmcminn]

I really appreciate everyones help on this one, thanks. An eventual project will be to build a little access panel to tuck everything away behind.

Micah, the yellow glass fuse is 3 amps and is inline to the Garmin GPS and connects to a 3A blade fuse on the fuse block. Any idea why?



Also, do you know why I have a ground bus bar in addition to the ground portion of the fuse block? I ran the positive from the 12V and USB to the fuse block and used 15A and 5A fuses and ran the negative to the ground bus bar. Should I have grounded them on the fuse block? It all works...





One last question, kinda two really, why didn't the person who wired it heat shrink the connectors? And should I (someday) pull them and heat shrink them and also use dielectric on all that exposed stuff?

Thanks. It all worked on my trip and made it much more comfortable.

[ssobol]

[Micahbigsur@msn.com]

Yes unless in a damp or salt spray area no need to use heat shrink, though anything you add you can use crimp terminals that have the built in heat shrink.
Many things get added at different times in boats, if someone wanted an added ground they add a buss bar, that is fine, that one is a good one of a newer Blue-Seas style. It is neater if both the +&- are tied in close together. Make sure that both negative bars are tied together directly and not all the way back through the batteries, then they are essentially one.
The yellow glass fuse came with the unit so it could be tied directly into the positive 12v, in your system it is extraneous, adds another problem point just directly from the blade fuse is better...but make sure in your manual that it is a normal glass fuse not a "fast blow" or other weird fuse which is unlikely. If the fuse in it just says 3 amp it is the same as the blade fuse.
Try to bundle parallel wires with zip ties for neatness to avoid the rats nest look but I would not rewire what is working, adding new wires, run them alongside others and tie them together also neater, every time you undo a screw or add something use dielectric.
Good luck!

[thataway]

I agree with the above, except for one factor. That is I do use heat shrink where ever possible, especially if the boat is used in salt water. Just the salt air has enough salt to make corrosion more likely in the wires.

I have rewired 20 year old boats, which were kept in salt water, and even the Ancor tinned wiring which was in the interior had some corrosion. Any non tinned wire had extensive corrosion. The heat shrink terminals (there are some decent ones from China which are cheaper than Ancor in bulk), work very well, and you don't have to add adhesive heat shrink tubing, unless you damaged the outside of the insulation with the crimper.

As Ssobol, I have boxes of all size of adhesive heat shrink--cheaper if you buy in bulk..

I would not undo, unless you want to for neatness at this point. I would use the dielectric grease with all screw contacts.

As for the negative bus bar: it was probably put in for those items on the outboard size of the console. When you go along, you may want to shorten the coiled wire (except the outboard harness)

[BrentB]

Are all connected devices working?
I would take the time the trace each connection and label them and draw a diagram.
At some time, start cleaning up the wiring will better crimp, shortening wires and securing them

[Chester]

Rather than di-electric grease I have started using NO-OX-ID which is supposed to improve conductivity and resist corrosion.
Is it that much better? I don't know yet but it gives me a warm fuzzy feeling.

https://www.sanchem.com/electrical-contact-lubricant.html

[Micahbigsur@msn.com]

Check the Practical Sailor testing of several anti corrosion products I seem to remember that NO-OX-ID was made with grey aluminum powder for home wiring an did not do well when mixed with copper and salt air. I used it until reading the review and have gone over to the insulating non metallic, more water resistant qualities of silicone diaelctric grease

[Chester]

OK, I found the article you mentioned. It is worth a read for all boat owners.
Luckily for me the NO-OX-ID does not have metallic dust which can be a problem.
http://www.bwi.org/bwicontest/files/2972-coppergrease_geartest.pdf

[BrentB]

good article! Thanks

[Micahbigsur@msn.com]

Chester, it was good of you to find that article I was too lazy to drag out all my old issues to find it and using my phone gets tedious.
I see that I was using Noalox it's been a while and I had always used it wiring houses where it is very common.
Practical Sailor seems to like Green Grease which I wouldn't expect, I've used the lanolin based water resistant Lanocoat but I always thought that it was too messy for wiring. I wish they would test my favorite silicone diaelctric grease that I buy in large tubes at an electronics supply. I have done extensive wiring with it on 3 salt water boats over the last 15 years and on the Ranger Tug with a crazy amount of wiring and electronics under the leaky cockpit hatches it really saved me. I also find it works great on water filter o rings, hatch gaskets, stainless threds and sticky window slides, being muti-use it makes the cut for our limited storage space.
Thanks again!

[Micahbigsur@msn.com]

Deleted double!!

[Chester]

You're welcome. Thanks for bring it's existence up.

[SelmaAdam]

You may take this into consideration
To find the total amperage in your specific installation, refer to the table below. Find the items that you're installing and their current requirements. Add the values and divide by 1000 to get your total current in Amps. You can use this value in the fuse size chart above to determine the minimum wire size required.

[ssobol]

ABYC wire sizer app

https://abycinc.org/page/wiresizer#:~:text=The%20ABYC%20Wire%20Sizer%20app,are%20based%20on%20ISO%20requirements.