Proliferation of fuses...

R

rogerbum

New member
It seems like everything I buy and everything that came with the boat (VHF, sonar, radar, radio etc) has an inline fuse on the hot lead. Typically, these items are wired through a switch to the main electrical panel where the source power is fused again. One thing I've noticed while working on wiring new things into my boat is that there's a plethora of inline fuses in various locations. It seems to me that this will make trouble shooting very difficult as many items have more than one fuse and the inline ones may be hidden. So, I'm thinking of spending a few days this spring/summer tracing down all the inline fuses on the boat and removing any fuse that's inline to a power source that's also fused off the main panel with the exception of the following inline fuses - bilge pumps, downrigger wiring (both high current and fused near the battery), the wallace and the main inline fuses for the power feeds to the panel (again fused near the battery). Anyone see anything wrong with this?
 
The fuse protects the wiring or device DOWNSTREAM of the fuse (away from the power source).

A GPS uses very little power and has an inline fuse to protect the device. Removing that fuse then requires installing a fuse or circuit breaker of the SAME amperage as the one removed. It may not be possible to put a very low amperage fuse in the fuse holder at the switch on the panel. Circuit breakers of a very low amperage may not be available.

Removing an inline fuse from a device could also void the warranty.

I obtain spare fuses and then tape, or attach the spares near the inline fuse for each device. The very small inline glass fuses used on GPS or VHFs are not easy to locate while out cruising.
 
Larry H":35gq1oe8 said:
The fuse protects the wiring or device DOWNSTREAM of the fuse (away from the power source).
Click to expand...
Yes - but typically these fuses are in series with ANOTHER single fuse in the buss. So it seems to me that one could simply put the lower amperage fuse in the buss to begin with. That fuse is between the power source and the device and hence is generally protecting even more wiring than the one close to the device.

Larry H":35gq1oe8 said:
A GPS uses very little power and has an inline fuse to protect the device. Removing that fuse then requires installing a fuse or circuit breaker of the SAME amperage as the one removed. It may not be possible to put a very low amperage fuse in the fuse holder at the switch on the panel. Circuit breakers of a very low amperage may not be available.

Removing an inline fuse from a device could also void the warranty.

I obtain spare fuses and then tape, or attach the spares near the inline fuse for each device. The very small inline glass fuses used on GPS or VHFs are not easy to locate while out cruising.
Click to expand...

The problem in my mind isn't so much about having the correct fuses on board (although I agree that can be difficult), the problem is that there are so many inline fuses in so many different (and non-standard) locations that it can make trouble shooting difficult. I'm guessing that the manufacturers default to an inline fuse so that a bubba can hook it directly to the battery on his bass boat and still be protected. It seems to be that an identically sized fuse in the buss would not only provide the same protection, it would often be closer to the power source (and thereby protect more wiring). I agree though that it might not be possible to always find blade fuses of the correct amperage but I have found the mini blade styles rated as low as 2A and I rarely see less than 2A inline fuses in my electronics.
 
Not all fuses are the same. Some electronics have fast blow fuses to limit the damage to internal components. Make sure you replace the inline Mfg's fuse with a fuse of the correct rating. Sometimes it doesn't make a difference but it doesn't hurt to check.
 
I ran into the same issue while doing some rewiring this winter. I have have a Raymarine C-80, a VHF radio, AM/FM radio and fan all located overhead in the equipment shelf area. The amount of DC wiring heading down to behind the helm was getting out of hand. I finally put in a DC distribution bus between the two front windows just below the equipment shelf and took everything to that using the in line fuses. The connection to main panel is also fused using the total load anticipated on the bus. It sure made things a lot cleaner and seemed to make more sense electrically since all the wiring runs were under 12 inches.
 
I end up putting in second, and occasionally 3rd fuse blocks and run the electroncis off those--removing the inline fuse--and using a comperable fuse at the fuse block. This will also give you a chance to label all of the wires.
 
I like to use buss bars or fuse blocks and get rid of the inline fuse on the item to be installed. Just make sure the fuse on the block will handle and protect the item usually the same amperage. This as bob says makes it easier to label stuff and cleans up the install. Also longer term it gives better service as the power tends to be more consistant.
Therefore properly installed you just turn on your battery selector then power up your GPS or radio, no need to first turn on a toggle switch.
George
 
***

I just posted 3 photos of our 2008 TomCat fuses
located in the starboard stern of Lady KC.

I there anyone out there that is able to give me some direction
on how I can determine the function of each fuse
shown in the photos.

I hope to be able to label each fuse for future reference.


I have printed off the TC wiring diagram from the web site,
so that will give me a start to physically try and trace the wiring.

***
 
Thats easy. turn on everything in the boat and pull a fuse. What ever goes off is on that fuse. trying to trace wires thru a bundle of wires and around over and under the interior of the boat is a pain.
 
The wiring has "evolved" thru the years. Assuming that these are factory installed (including the VSR"s) in some ways this is better than the Tom Cat which was built in 2006. I would trace out the wires to each "appliance" (could be bilge pump, stove or macerator ) Then use one of the labelers to put a 3/8" wide label around each wire. Unfortunately sometimes the color of the wire does change--but usually you can trace it out.

I like the idea of a fuse block back in the lazaretto area (the 2006 only had in line fuses)--but this area is high humidity, and corrosion can be a bit of a problem. The 2006 boats had the rubber fuse holders which you can coat the fuse and the holder with dielectric anti corrosion grease, for some protection against corrosion.
 
Roger,

I really like your idea as I have also worried about all the fuses I haven't discovered yet. I would like to check one or two places when something electrical stops working or a continuous draw appears draining batteries.

I think I want a front fuse area at the helm and one in the stern.
 
An absolute wealth of good ideas and information. As one that has had over the years a great many boats that all have more than one add on I found that making a list of where the fuse or in line fuse is located really helps. At any inline fuse I attach a large tag as to what it protects. Having a readily available laminated list to grab which indicates the location and type of fuse helps. I always keep an ample supply of fuses available and in one location. It has made life easy on several occasions.

H :wink:
 
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