In-Line Fuses??

[ChrisfromVT]

I'm taking down all the wiring form my switchboard and some components have in-line fuses. What's the purpose of these fuses?...Is it simply to protect the entire board from frying in the event of a short? Given this, should bilge, lights, etc have inline fuses for each circuit?

Thanks!

 

[Bob_VT]

Re: In-Line Fuses??

Chris the inlines are cheap ...... it saved the manufacturer money. I hate fuses on a boat but marine circuit breakers are great (napa) but do cost a bunch more money.

 

[Daviet]

Re: In-Line Fuses??

All the circuts should be fused. I prefer to install a fuse panel and run everything off of the panel. Some people use in-line fuse holders because they don't have a panel or are to lazy to wire the circut to it. I find the in-line fuse holders can cause problems, they loosen up or carode inside.

 

[Woodnaut]

Re: In-Line Fuses??

You've got it right, Chris. The purpose of any fuse is to provide protection to the device, the wiring and the other circuitry. For example, bilge pumps pull a lot of current. If a bilge pump were to experience a dead short in the windings, there is a good chance that the high current draw would generate enough heat in the wiring (or the pump itself) to melt insulation or possibly even cause a fire. In this case, the fuse will interrupt the current, prevent a hazardous situation, and let you (the owner) know that something is wrong.

When a circuit is designed, the proper number and size of fuses are designated and included in a fuse block that might hold 4 or 6 or more fuses. Typical items which would have their own fuse are the navigation lights, bilge pump, live well pump, horn, accessory lights, and (one or more fuses for the) electronics.

In-line fuses are sometimes part of "add on" installations. That is say, something that was added to the boat after its initial construction. For example, a radio. Sometimes "spares" are provided on the fuse block during the initial construction. If you have a spare fuse, then adding on an extra accessory is not problem. If not, then an in-line fuse can be added.

I really don't like in-line fuses because sometime they are cheaply constructed and not always located where they can be easily seen, protected and serviced.

 

[robert graham]

Re: In-Line Fuses??

I have some in-line fuses for the depth finder and others, they are cheap and can corrode causing bad connections. So remove the fuse, clean it and the contacts, put some silicone grease on the ends of the fuse to keep out moisture, re-install, and no more problems. A nice professionally installed fuse box is great, but so this is working fine. Good Luck!

 

[ChrisfromVT]

Re: In-Line Fuses??

Thanks so much for the info guys!
Sounds like a fuse panel behind the dash is the way to go. Will most components take the same size fuse?

 

[Woodnaut]

Re: In-Line Fuses??

Each componet should be fused according to it's current draw. For example, I might put a 3A fuse on the radio, but that wouldn't cut it for the bilge pump (which pulls a lot more current). Take a look in the Electronics Section of this forum and you'll see more info on this subject. I think there is also a "generic" wiring diagram listed there as well.

One more comment on silicon grease. I operate in salt water almost exclusively and corrosion is major consideration. I have a small amount of silicon grease on every metal wiring component in my boat's electrical system. Every ring terminal, every fuse, every screw terminal, everything. (Almost 10 years without a failure.) Put a small amount of grease on permanent connections before you make the connection. Putting it on afterward will prevent surface corrosion, but will not necessarily prevent corrosion that can occur in between the contact surfaces. (The silicon grease will not inhibit current flow through a connection.) Again, you might want to search in the Electronics Section on this subject a bit.

 

[triumphrick]

Re: In-Line Fuses??

Each componet should be fused according to it's current draw. For example, I might put a 3A fuse on the radio, but that wouldn't cut it for the bilge pump (which pulls a lot more current). Take a look in the Electronics Section of this forum and you'll see more info on this subject. I think there is also a "generic" wiring diagram listed there as well.

One more comment on silicon grease. I operate in salt water almost exclusively and corrosion is major consideration. I have a small amount of silicon grease on every metal wiring component in my boat's electrical system. Every ring terminal, every fuse, every screw terminal, everything. (Almost 10 years without a failure.) Put a small amount of grease on permanent connections before you make the connection. Putting it on afterward will prevent surface corrosion, but will not necessarily prevent corrosion that can occur in between the contact surfaces. (The silicon grease will not inhibit current flow through a connection.) Again, you might want to search in the Electronics Section on this subject a bit.

This is some good info...silicone grease and dielectric grease is even sold at your local HD or Lowes, in the electricla department. Another connector to keep in mind is the shrinkable ring, fork or inline connector that you can buy there as well. You can also cover that terminal with shrink sleeve for some added protection. Keeping salt water or moisture off those will greatly reduce electronic issues...

 

[mike343]

Re: In-Line Fuses??

Fuses, in general, aren't there to protect against the failure that caused the fuse to blow if the failure is inside the device. They may limit the damage done so that the unit is repairable. They do protect against external shorts and protect the wiring against hard shorts.