Fuse placements and sizing

[CapPugwash]

Hello matey-boaty-peeps

Currently re doing the power distribution on my Vancouver 32 and am looking for some advice on fuse placements, sizing, life and the meaning of everything.

My batteries, starter motor and main busbars are all already connected with 35 mm2 Tinned OceanFlex and I am planning to do the rest in 16 mm2. I have highlighted the fuses in yellow. What do you think?

EDIT : Updated Diagram to show revised fuse placement as per suggestions in this thread.

 

[pandos]

Hello matey-boaty-peeps

Currently re doing the power distribution on my Vancouver 32 and am looking for some advice on fuse placements, sizing, life and the meaning of everything.

My batteries, starter motor and main busbars are all already connected with 35 mm2 Tinned OceanFlex and I am planning to do the rest in 16 mm2. I have highlighted the fuses in yellow. What do you think?

View attachment 130431

I am doing the same thing at the moment.

I am jealous of your ability to make such a clear diagram...I am working on the basis that I will make a sketch of mine when it is done...

The main difference in my approach and yours is I have the battery charger, alternator and solar feeds fused individually just before they connect to the batteries and I took the alternator directly to the battery instead of to the starter feed...

 

[CapPugwash]

I am doing the same thing at the moment.

I am jealous of your ability to make such a clear diagram...I am working on the basis that I will make a sketch of mine when it is done...

The main difference in my approach and yours is I have the battery charger, alternator and solar feeds fused individually just before they connect to the batteries and I took the alternator directly to the battery instead of to the starter feed...

I'm a network engineer, so i use Visio all the time. I recommend drawing as you go otherwise you won't get round to it before you forget, at least on paper anyway.

So i have my fuses at the charger source, with the exception of the alternator where the fuse is next to the battery, but that is based on the Starter Motor drawing its CCA from the battery.

 

[starfire]

I'm a network engineer, so i use Visio all the time. I recommend drawing as you go otherwise you won't get round to it before you forget, at least on paper anyway. So i have my fuses at the charger source, with the exception of the alternator where the fuse is next to the battery, but that is based on the Starter Motor drawing its CCA from the battery.

Remember, the fuse is there primarily to protect the cable, better fused as near to the battery as is practical

 

[CapPugwash]

Remember, the fuse is there primarily to protect the cable, better fused as near to the battery as is practical

Yes, but isn't that the source? Because that end of the cable is where the full force of the draw is. So in the case of a cable connected to charger that would be next to the charger.

That's how it works in my head anyway ?

 

[pandos]

Yes, but isn't that the source? Because that end of the cable is where the full force of the draw is. So in the case of a cable connected to charger that would be next to the charger.

That's how it works in my head anyway ?

In some ways you are correct but in reality if a fault occurrd the charger will probably stop the feed even if it has melted, but the battery will still be able to throw a few hundred amps, potentially into the short or melted charger...

I have put 30 amp midi fuses on all of the light stuff and mega fuses on the heavy feeds, with subboards using blade or glass fuses down to 5amps (ish)

 

[CapPugwash]

In some ways you are correct but in reality if a fault occurrd the charger will probably stop the feed even if it has melted, but the battery will still be able to throw a few hundred amps, potentially into the short or melted charger...

I have put 30 amp midi fuses on all of the light stuff and mega fuses on the heavy feeds, with subboards using blade or glass fuses down to 5amps (ish)

Thank you. That makes sense!

 

[pandos]

Thank you. That makes sense!

I got that advice on here and when I looked at my original system I got the collywobbles...

 

[CapPugwash]

I got that advice on here and when I looked at my original system I got the collywobbles...

Yes, this forum is great isn't it. I have received loads of great advice on this project.

 

[Stemar]

For simplicity in use, I'd group the fuses as much as possible, even if it means longer cable runs. The last thing you want when one goes on a dark and stormy night it to be wondering WTF is the fuse for that! Also, use fuse holders or fuses with LEDs, so you can see which one's died. Finally, treat yourself to a label maker and label every fuse and every wire termination. Future you will thank you.

 

[CapPugwash]

For simplicity in use, I'd group the fuses as much as possible, even if it means longer cable runs. The last thing you want when one goes on a dark and stormy night it to be wondering WTF is the fuse for that! Also, use fuse holders or fuses with LEDs, so you can see which one's died. Finally, treat yourself to a label maker and label every fuse and every wire termination. Future you will thank you.

Group fuses together = Check
Label Printer = Check (specialist cable one too - I play at being a network engineer at the moment)
Fuses with LEDs = Oooooooo! Now I never knew about these, what witch craft is this?!!!?

 

[billcole]

Yes, but isn't that the source? Because that end of the cable is where the full force of the draw is. So in the case of a cable connected to charger that would be next to the charger.

That's how it works in my head anyway ?

The fuses are there for when things aren't working as normal though.
Imagine a cable that runs through a cockpit locker, say, and one day in heavy weather the dinghy outboard that is stored in that locker crashes about and the cavitation plate cuts through the cable insulation and bridges between the +ve and - ve conductors.
If there is a fuse somewhere between the battery and the damaged point in the cable then that fuse will blow and all will be well( ish).
If, however the fuse is beyond that point then hundreds of amps will flow and either the copper cable will melt through before setting fire to anything else, or it won't and the crew will have a blaze to extinguish.
The closer all fuses are to the battery the less cable there is where that sort of thing can happen.

 

[Stemar]

Fuses with LEDs = Oooooooo! Now I never knew about these, what witch craft is this?!!!?

Here you go

Standard Blade LED 'Glow' Fuses



Alternatively, get ordinary fuses and one of these

 

[pandos]

This is what I am using where most of my nav and electronics stuff are connected.

https://www.amazon.co.uk/dp/B07YDF3...t_i_E1KEX0KZ32150YYK925K?_encoding=UTF8&psc=1

My nav lights are going to a set of 5 switches and one fuse, with all other devices switched/fused on the original panel.

I got a dymo label printer from Aldi and non dymo plastic labels on Amazon.

 

[VicS]

Here you go

Standard Blade LED 'Glow' Fuses



Alternatively, get ordinary fuses and one of these

But will the blade fuse holders accept the 16mm² cable Capt PW is intending to use?

His diagram shows Mega and Midi fuses

.The input stud will accept a ring terminal on 16mm² but the 6.3mm outlet spades will limit the size.

(Those boxes also avaialble with 4 or 6 fuses)

 

[CapPugwash]

This is what I am using where most of my nav and electronics stuff are connected.

Blade ATC/ATO fuse blocks, ENDARK car fuse holder, 12 way fuse box with Negative Bus LED indicator for Car, Boat, Van, SUV : Amazon.co.uk: Automotive

My nav lights are going to a set of 5 switches and one fuse, with all other devices switched/fused on the original panel.

I got a dymo label printer from Aldi and non dymo plastic labels on Amazon.

I'm using a Brady BMP41 that I have borrowed from work.

 

[CapPugwash]

But will the blade fuse holders accept the 16mm² cable Capt PW is intending to use?

His diagram shows Mega and Midi fuses

.The input stud will accept a ring terminal on 16mm² but the 6.3mm outlet spades will limit the size.

(Those boxes also avaialble with 4 or 6 fuses)

Those 16mm2 will be Midi fuses, but the device connections will use those type so I'll consider them for those.

Thank you all.

 

[Sandy]

Here you go

Standard Blade LED 'Glow' Fuses

View attachment 130458

Well, I am at a loss for words! Surely this is an April Fools Joke. I know it's not I've looked at the website.

On a dark and stormy night my nav lights go out. Oh gosh I wonder what fuse it could be? One circuit, labeled and you need a wee LED to tell you what the blown fuse is. I think most people could find and fix the fuse blindfolded.

 

[Stemar]

In poor light, it can be quite difficult to see if one of those fuses has blown. Since the difference in price is minimal and I don't change fuses very often - usually self-inflicted, I figure it's worth it.

 

[pandos]

In poor light, it can be quite difficult to see if one of those fuses has blown. Since the difference in price is minimal and I don't change fuses very often - usually self-inflicted, I figure it's worth it.

Those with good eyesight will eventually realise how blind those old codgers with fogged up glasses become. so unless the labels are in neon letters 2 inches high they may be useless on ocassions.

Mine have fixed leds which illuminate if a fuse blows, so ordinary blade fuses are used ( decent bag of which came with the item) also ring terminals rather than blades.