Quick question about fuses for fish finder.

[Douglasdzaster]

I’m finishing rewiring my boat and got a new Garmin in the process.
I cut off the fuse holder they had on it which was for glass fuses. I used step down butt connectors and ran my 14awg to the fish finders own battery and put an inline fuse holder for blade fuses at the battery (everything else goes through a switch panel and fuse block except for the bilge pump). Again instead of leaving the one it came with way down the line. I fuse everything at the power source.
I was reading about my new Garmin some more the other day and noticed it said to be sure and use fast acting or fast blow fuses.
I started researching and I keep coming up with the old glass fuses as being fast acting.
My question is are there fast acting blade fuses and should I even be worried about it? It’s just a 3 amp that would probably go quick anyway.
Thanks for any opinions and advice.

 

[Still Afloat]

Fast acting fuses are common for electronics. I would recommend that you do two things:
1. Leave the fast acting fuse inline (or put it back in).
2. Read the specifications and size the blade fuse at the power supply at about 140% of the maximum current draw. I’m guessing a 2 amp fuse if the Garmin is the only thing on that circuit. A five amp should be fine too (Assuming the wire gauge will accommodate that current.) since the blade fuse is really just protecting for short circuits in the wiring to the fish finder.

 

[Douglasdzaster]

Fast acting fuses are common for electronics. I would recommend that you do two things:
1. Leave the fast acting fuse inline (or put it back in).
2. Read the specifications and size the blade fuse at the power supply at about 140% of the maximum current draw. I’m guessing a 2 amp fuse if the Garmin is the only thing on that circuit. A five amp should be fine too (Assuming the wire gauge will accommodate that current.) since the blade fuse is really just protecting for short circuits in the wiring to the fish finder.

Thanks for the reply. Garmin says 3amp. I think it draws like 1/2 amp.
I feel like I was being a smart elicit now cutting out that fuse. I clipped it off pretty short too. I’ll get another marine grade inline holder and put a fast acting 3 amp glass fuse in it.
And yes it’s an 18ah sla battery just for the Garmin. I even ran all other wiring down the other side of the boat so it would be away from the transducer cable running to the transom.
Thanks again for the advice.

 

[Sea Antsy]

Thanks for the reply. Garmin says 3amp. I think it draws like 1/2 amp.
I feel like I was being a smart elicit now cutting out that fuse. I clipped it off pretty short too. I’ll get another marine grade inline holder and put a fast acting 3 amp glass fuse in it.
And yes it’s an 18ah sla battery just for the Garmin. I even ran all other wiring down the other side of the boat so it would be away from the transducer cable running to the transom.
Thanks again for the advice.

While your "fuse-in" consider a liberal application of dielectric grease on every exposed and hidden metal conductor.. fuses,fuse holders,lugs, battery terminals,spark plug boots... ect...

 

[Douglasdzaster]

While your "fuse-in" consider a liberal application of dielectric grease on every exposed and hidden metal conductor.. fuses,fuse holders,lugs, battery terminals,spark plug boots... ect...

All ready there sir. Finishing up a complete rewiring. Used all Ancor marine tinted copper wire and Ancor crimp and heat shrink connectors. A Blue Seas fuse block and new switch panel.
There’s dielectric grease around every spade connector and every lug. A couple of things I wired straight to the battery have in line fuses with dielectric grease around the seal.
Question though. You mentioned the connecting parts like the fuses them selves. I’ve seen and heard so many times not to put it on the circuit it self but use it to seal. Like using it on just the porcelain spark plugs. The reason given is dielectric grease does not conduct electricity and will effect the current.
Then I hear that it’s a great conductor. Which one is correct? I have blade fuses installed 2 years ago I just put it around the seal and when I pull the cap off the grease is there and the fuses look new.
But I’d really like to know if it conducts electricity well or does it effect the current? It’ll make me change the way I’ve been using it.

 

[Still Afloat]

Dielectric grease is an insulator. Use it around connections but not on them.

 

[Douglasdzaster]

Dielectric grease is an insulator. Use it around connections but not on them.

Thank you. That’s how I’ve been using it but I see a lot of people giving advice otherwise because they think it’s a great conductor.

 

[Sea Antsy]

Dielectric grease is an insulator, it neither conducts electricity nor increases any resistance in any MECHANICAL-ELECTRICAL connection.
If grease prevents or inhibits any electrical flow of current you have a MECHANICAL-ELECTRICAL connection problem.

 

[Douglasdzaster]

Dielectric grease is an insulator, it neither conducts electricity nor increases any resistance in any MECHANICAL-ELECTRICAL connection.
If grease prevents or inhibits any electrical flow of current you have a MECHANICAL-ELECTRICAL connection problem.

Thanks for the reply. This is good stuff.

 

[LDUBS]

Dielectric grease is an insulator, it neither conducts electricity nor increases any resistance in any MECHANICAL-ELECTRICAL connection.
If grease prevents or inhibits any electrical flow of current you have a MECHANICAL-ELECTRICAL connection problem.

Thanks for the reply. This is good stuff.

X2 -- thanks.

Is dielectric grease good to use on our trailer plugs?

 

[Sea Antsy]

Its a lubricant.. and anti corrosive..
EVERYWHERE.. except.. well this is a family rated site so i won't go there.. but..
I live on an island, salt water on all sides.. even light bulbs in outdoor fixtures on the house corrode without some protection..
I use it everywhere.. and have, on submarines, destroyers, tenders, cars and trucks, houses..
think/look anywhere you do not want corrosion.. it does not harm plastic or rubber.. think of all the O-rings on a boat..
fuel fill, hoses, electrical connectors.. ie Bullet connectors.. on power washers that dang little O-ring..
sure.. pack the trailer plugs both sides the truck and the trailer with it.. take the light bulbs out.. clean the base, then the socket then
get out the q tips and do both sides..
do the VHF radio antenna connectors, only thing you might not be able to get to is the small multi pin connectors on the Fish Finders/Gps
there I spray with CRC6-56 much more liquid and gets in deeper..
Ok.. there is my confession.. let the flames begin..

 

[Still Afloat]

Dielectric grease is used to inhibit moisture intrusion. A good example is to lubricate boots, like fuse boots or spark plug boots. In other words, don’t grease the actual fuses, eye connectors and other electrical metal to metal connections.

To prevent corrosion on open metal to metal connections (like on a terminal or fuse block) then use a conductive corrosion inhibitor.

 

[David Atkins]

The substance works by creating a physical barrier between two surfaces. The grease coats one of the surfaces and acts as a shield against outside elements such as water, dust, and salt.

When applied to battery terminals, it forms a layer of protection against corrosion and prevents other chemicals from contacting them.

Is Dielectric Grease Conductive?​

Despite the ‘electric’ in its name, dielectric grease does not conduct electricity. It barely allows electrical interference. Hence, it needs no telling that it won’t improve electrical current flow in any way despite some beliefs otherwise.

It’s also why you shouldn’t apply it to sockets or pins that need to make a solid connection. Too much dielectric grease can compromise the quality of the connection.

 

[thill]

I have used it everywhere for many years, including on electrical terminals, but only apply a THIN FILM, not globs of it everywhere. I like to apply it with a Q-tip, as that helps spread it evenly without putting on too much.

As stated earlier, if not overdone, it won't interfere with conduction, but in the long run it will prevent a lot of problems

 

[Douglasdzaster]

Thanks for all the answers! Now I know I’ve been using it correctly.
The only thing I have not used it on is battery terminals. When I’m not using the boat they stay removed. That’s a lot of connecting and disconnecting. I have been using a spray on battery terminal protector that seems to work.
Besides fuses I use dielectric grease with all fuses and where the fuse holder cap closes. Especially on unprotected connections like trolling motor breaker , main battery switch.
I just installed a led light strip yesterday and they have wire to connect to on both ends. I clipped off the exposed wire on the end put dielectric grease and sealed it up.

 

[Douglasdzaster]

Its a lubricant.. and anti corrosive..
EVERYWHERE.. except.. well this is a family rated site so i won't go there.. but..
I live on an island, salt water on all sides.. even light bulbs in outdoor fixtures on the house corrode without some protection..
I use it everywhere.. and have, on submarines, destroyers, tenders, cars and trucks, houses..
think/look anywhere you do not want corrosion.. it does not harm plastic or rubber.. think of all the O-rings on a boat..
fuel fill, hoses, electrical connectors.. ie Bullet connectors.. on power washers that dang little O-ring..
sure.. pack the trailer plugs both sides the truck and the trailer with it.. take the light bulbs out.. clean the base, then the socket then
get out the q tips and do both sides..
do the VHF radio antenna connectors, only thing you might not be able to get to is the small multi pin connectors on the Fish Finders/Gps
there I spray with CRC6-56 much more liquid and gets in deeper..
Ok.. there is my confession.. let the flames begin..

Thanks for the CRC I was just wondering what to use on the pin connectors on my new fish finder. Before I just cleaned regularly with an electrical cleaner.

 

[Still Afloat]

I’ll just agree to disagree.