Boat wiring - what am I missing?

[Jd1]

Today I attempted to install a dedicated GPS puck for my VHF radio. The plan was to tap the radio power wire after the fuse to power the DC-DC converter (5V) for the puck. After about an hour of frustration punctuated by very expressive language, I finally managed to reveal most of the power wire (2 feet) to the radio. It runs from the switch panel (VHF switch) directly to the radio. The in-line fuse that originally was part of the power wire is nowhere to be seen. There are a number of in-line fuses on the back of the power panel for various unknown other items so the previous owner seemed to be aware that fuses are a good thing. BTW, this is a 2005 or thereabouts boat and the electrics are pretty clean looking. I assume the radio was one of the first things installed which is why it took so long to expose the wires - a lot of other stuff had to be removed or discombobulated (technical talk) before I could get to the wires in question.
Looking at the power panel, I see that a few (very few) of the switches have current ratings which to me implies they are breakers. The VHF switch does not.
Is it standard practice to use straight switches in the power panel rather than a fused switch? There are an awful number of straight switches and there are a lot of in-line fuses all over the boat. Without tracing each wire, I have no idea if a particular line has a fuse anywhere. Heaven help me if a fuse actually blows someplace - since they are not in one standard location, any repair involves trying to trace wires in order to hopefully locate a fuse someplace. Is this standard procedure ? If so, what the heck is the justification?
What protects the wiring if the fuse is located close to the device being powered - for example, my heating fans have fuses very close to them. What happens if the power wires chafe as they go through a bulkhead and a short circuit happens? The way it looks to me is that the boat burns down. Surely this can't be normal procedure? BTW, I have no doubt that all the wiring in this boat was installed by professionals. The radio may be an exception.
Yes there are fuses by the battery but I would think that thin wires will light up and generate a fire before the high amperage battery fuses would blow.
Many questions I know but maybe I am just missing something very obvious in the philosophy of wiring boats .....

[svmariane]

Wow. Sympathies extended.

Quick response: your winter project seems to be to rewire your boat.

Yes, the VHF radio SHOULD have a fuse somewhere. If not, install one.

Pain in the backside (I know) but from your description of the wiring you'll need to suck it up and trace out everything aboard.

Back story: I did that tracing stuff after buying our boat - MAN was I confused and T'eed off at what I found. Ended up buying new electric panels with circuit breakers and rewiring everything aboard except the (built in) overhead lights and the motor's gauges.

Good luck! Again... Sorry about your winter task.

[Stu Jackson]

Have you asked this on the C36IA Forum?

[Jd1]

Originally Posted by Stu Jackson

Have you asked this on the C36IA Forum?

I am assuming you are talking about the Catalina 36 forum ... if so, the answer is no ... although that is something I never thought about. I am not a member there but I will look into it. Thanks!

[Target9000]

Personally, I'd take all the wires and trace and label them. This shouldn't be overly hard just tedious. I'd install a fuse block behind the panel and make sure everything passing through the panel goes through the fuse block. An alternative would be to convert to a breaker panel instead. You need to size the breakers/fuses to their wires.

On our boat we gutted all the wiring and started fresh. I kept finding stuff like this:



It wasn't as bad as I thought it would be.

[Wotname]

Originally Posted by Jd1

........ BTW, I have no doubt that all the wiring in this boat was installed by professionals. The radio may be an exception.
Yes there are fuses by the battery but I would think that thin wires will light up and generate a fire before the high amperage battery fuses would blow.
Many questions I know but maybe I am just missing something very obvious in the philosophy of wiring boats .....

The most obvious thing is that this undoubted professional is/was anything but professional.

From your description, there is not one professional attribute about this job.

There are many issues but here are some that stand out immediately.

>Fuses should be placed as close to the source as reasonably practicable.

>All wiring should be protected and rated for the wire size (or smaller) and motors have some special requirements (eg bilge pumps).

>All fuses (and especially in-line ones) should be labelled

>Fuses should be easily accessed

>In-fuses should only used where really necessary and should be located with "common sense".

I could go on but this is really an unprofessional job and I am surprised that others would consider it to be OK or normal.

[evm1024]

Trace out everything, label it and diagram it. As well as take photos for later reference. All will become clear after some time.

I also use a dedicated GPS (Standard Horizon in my case). A number of switches power the gps using isolating diodes and inline fuses. THis way the gps comes on when the VHF or chart plotter oe PS is powered on.


Regards

[MarkSF]

Proper practice is a breaker at the switch panel, protecting the wiring to the device. If necessary, an inline fuse near to the device can protect IT.

So for example : I have a 15A breaker for the VHF. 14 guage wire goes to the device, then an inline fuse.

One more elegant way to handle multiple devices on one breaker is an extra fuse box. I mounted one of these for the instruments, powered up by an instrument breaker.

http://shop.pkys.com/Blue-Sea-System...uits_p_15.html

Again : breakers protect the wiring, and prevent fires. Fuses near to the devices protect them. Wiring should be rated HIGHER than the breaker.