can someone let me know what fuse sizes?

[1975oday22]

i am rewiring my boat, adding a fuse block as one never came with it. what size fuses for the , blower, bilge pump, wiper, lights, horn, ect. going with a ten standard blade.

 

[rallyart]

Two factors on fuse sizes. First, never use a fuse that is above the amp rating of the wire gauge going to it. Melted wires are dangerous. Second, don't use a fuse higher than the expected load justifies. You want the fuse to blow before a fire starts on a blower motor, for example. Search for amp ratings of wire gauge sizes and you can read the amp ratings on things you will attach to the circuit. On a boat is is nice to have individual circuits for individual items if you can wire it that way.

 

[Scott Danforth]

your fuse size should be 1.25 x your load for each circuit.

fore example, the bilge pump should be 8 amps, that would be a 10 amp fuse

 

[dingbat]

Fuse to wire size, not component to maximize circuit capabilities.

It’s not a hose… fusing does not limit the amount of current being feed to the component. It limits the amount of current a component can draw from a power source.

 

[Scott Danforth]

Fuse to wire size, not component to maximize circuit capabilities.

It’s not a hose… fusing does not limit the amount of current being feed to the component. It limits the amount of current a component can draw from a power source.

ABYC E11 begs to differ

fuse size is based on the device(s) being protected, however should not exceed the conductor capacity.

 

[dingbat]

ABYC E11 begs to differ

fuse size is based on the device(s) being protected, however should not exceed the conductor capacity.

Paragraph number please......

11.10.2.3 The current rating of the overcurrent protection device shall not exceed the maximum current carrying capacity of the conductor being protected.

3. It is intended that the protection provided be generally equivalent to that of wiring permitted by this standard wherein a definite short or break would be necessary to produce an open spark.

 

[Scott Danforth]

Look at the load calculation section. I can post the exact section tomorrow

 

[1975oday22]

and so begins the debate..... what did i do? a simple question and einstein get into it... wow. a simple chart would of sufficed here gentlemen....

 

[froggy1150]

Here is an ampacity chart. You want your fuse to blow before exceeding the ampacity of the wire if it's dead shorted. Then from there you step down again to protect the device from burning. If you have a 10 amp device you run a wire to carry 15 amps and fuse at 10 amps for the device. If your existing wire can only carry 5 amps your device must be less and your fuse shall not exceed 5 amps.

 

[04fxdwgi25]

and so begins the debate..... what did i do? a simple question and einstein get into it... wow. a simple chart would of sufficed here gentlemen....

At least you didn't ask what is the best oil to use.

 

[dingbat]

Look at the load calculation section. I can post the exact section tomorrow

Don’t worry about it.

OP wants a chart…..not worth the time or effort to answer the question from a subjective viewpoint.

Still wondering why the mfg. recommends a 10 amp fuse for my 25W VHF radio.

It’s unfortunate that most will not get the joke…lol

 

[1975oday22]

Don’t worry about it.

OP wants a chart…..not worth the time or effort to answer the question from a subjective viewpoint.

Still wondering why the mfg. recommends a 10 amp fuse for my 25W VHF radio.

It’s unfortunate that most will not get the joke…lol

a normal car deck would run around a 5 amp a high powered i believe would run 10-15 the vhf radios should run around the same? if not a 20.... if my thinking is correct. i could be wrong. i know on my amateur radio VHF/UHF i was running 20 amp fuse.... that was 75w of power going through it. 12v

 

[JustJason]

i am rewiring my boat, adding a fuse block as one never came with it. what size fuses for the , blower, bilge pump, wiper, lights, horn, ect. going with a ten standard blade.

You should be fusing in accordance with the manufactures specifications for the component being fused. When new in the box, the blower bilge pump, wiper, horn ect would have had an owner's manual stating what size fuse to use. The issue with using a fuse of a higher rating on small electric motors is that if the motor rotor locks up and it's fused too high, the motor will catch on fire long before a fuse blow. Most people don't see bilge pump and blower motor fires, but they happen.

You should be fusing twice. The fuse in the fuse block is to protect the wire and should be rated for whatever the gauge and length of the wire run are. There should be additional fuses located as close as practicable to the component being fused. That fuse is to protect the component.

 

[Scott Danforth]

Still wondering why the mfg. recommends a 10 amp fuse for my 25W VHF radio.

It’s unfortunate that most will not get the joke…lol

because the volume goes to 11!?? LOL

 

[1975oday22]

just a lil update . fuse block is now in and operational. all wiring is now fused with correct fusing. will take pics later on. right now its a rats nest so wires have to be tie wrapped into place.

 

[1975oday22]

ok so here is the finished product. still have to adjust the stereo wires but fuse block and everything connected and working as it should.

 

[04fxdwgi25]

Personally, I would do some reading up and watching videos of proper marine / boat wiring techniques and best practices.

 

[1975oday22]

Personally, I would do some reading up and watching videos of proper marine / boat wiring techniques and best practices.

and what is wrong with the way i did my wiring? it works. and the right size wires and fuses. so what did i do wrong? oh wait. its not neat and tidy? is this a problem?

 

[04fxdwgi25]

I do applaud your incentive and effort to upgrade / improve the deficient existing electrical system, but taken a step further to ensure reliability and safety may have been warranted.

Neat and tidy would have been a goal for most, but isn't considered in this. Just suggesting that some insight would have been warranted. The circuits will work just fine, for now, until some corrosion or wiring overloads compromise the wiring / insulation / conncetions. Just because they work now, doesn't mean they will last over time.

A couple of examples:
Std automotive crimp connectors not suitable for damp marine environments. Should be sealed heat shrink.
Exposed live connections (should have used spade connectors that are fully insulated).
Spade connectors (yellow) for #12/10 wire used on small conductors. Crimp connectors should be sized for the wire size it is used on.
The 12VDC input is not protected from shorts.
Fuses protecting the circuits look to have wiring that is undersized for the fuse ratings (looks like some 30 amp fuses on that small wire)..
Tinned marine wire is highly recommended. The trailer harness wire is usually low quality and not tinned wire, which will cause corrosion forming in a short time.

 

[1975oday22]

I do applaud your incentive and effort to upgrade / improve the deficient existing electrical system, but taken a step further to ensure reliability and safety may have been warranted.

Neat and tidy would have been a goal for most, but isn't considered in this. Just suggesting that some insight would have been warranted. The circuits will work just fine, for now, until some corrosion or wiring overloads compromise the wiring / insulation / conncetions. Just because they work now, doesn't mean they will last over time.

A couple of examples:
Std automotive crimp connectors not suitable for damp marine environments. Should be sealed heat shrink.
Exposed live connections (should have used spade connectors that are fully insulated).
Spade connectors (yellow) for #12/10 wire used on small conductors. Crimp connectors should be sized for the wire size it is used on.
The 12VDC input is not protected from shorts.
Fuses protecting the circuits look to have wiring that is undersized for the fuse ratings (looks like some 30 amp fuses on that small wire)..
Tinned marine wire is highly recommended. The trailer harness wire is usually low quality and not tinned wire, which will cause corrosion forming in a short time.

no 30 amp fuses are in this unit. 3, 5 and 10 is all that is used. thank you for your concern. when crappy opens up on tuesday ill be sure to pick up some heatshrink and get that done. as for the connectors. i used what i had. automotive yes. marine no. as far as im concerned connectors are connectors. .....