Standardising on 12v fuses

[sarabande]

I presently have at least five different types of 12v fuse within a modest heritage electrical system.

For average circuits that do not involve self-contained pre-fused circuit boxes such as

ST Blade Fuse Block - 6 Circuits with Negative Bus and Cover - Blue Sea Systems

is it a practical target to just use blade fuses in a good waterproof holder like

GTIWUNG 10Pcs Car Inline Fuse Holder 32V, In-line Standard Blade Fuse Holder Waterproof 16AWG, Middle Fuse Holder Box, Medium Size DC Fuse Holder: Amazon.co.uk: Automotive

or are there any reasons to use different types such as a need for quick blow or slow blow fuses ? Are boat circuits (except radio ? ) capable of being sorted with one standard type of blade fuse of different ratings ? I would like to end up with a logical, tidy system with just one box of spare fuses, if possible.


signed Electrically Confused of Plymouth

 

[jwfrary]

Blade fuses are suitable for most dc powered things on a boat of fairly low power needs. Good quality ones are a must and not all fuse holders are made equally.

Circuit breakers can be a good idea for disribution as they are quickly reset.

Western electrical marine division is a good place to pick up these things (I assume your in plymouth uk from your last sentence!) No affiliation except for being a regular customer

 

[pandos]

I presently have at least five different types of 12v fuse within a modest heritage electrical system.

For average circuits that do not involve self-contained pre-fused circuit boxes such as

ST Blade Fuse Block - 6 Circuits with Negative Bus and Cover - Blue Sea Systems

is it a practical target to just use blade fuses in a good waterproof holder like

GTIWUNG 10Pcs Car Inline Fuse Holder 32V, In-line Standard Blade Fuse Holder Waterproof 16AWG, Middle Fuse Holder Box, Medium Size DC Fuse Holder: Amazon.co.uk: Automotive

or are there any reasons to use different types such as a need for quick blow or slow blow fuses ? Are boat circuits (except radio ? ) capable of being sorted with one standard type of blade fuse of different ratings ? I would like to end up with a logical, tidy system with just one box of spare fuses, if possible.


signed Electrically Confused of Plymouth

THERMAL FUSES /CIRCUIT BREAKER (manual reset) Range from 3A - 40Amp

These guys do a huge range of stuff including fuse holders like the Blue Sea one that you linked to.

I am in the process of reviewing my set up and am having difficulty convincing myself to spend a load of extra cash just to avoid having different types of fuses...

I think I am going to go for individual fuses as much as possible, grouped in different areas and and each group fed by a supply which is fused by something which is resettable and switched on my main panel..

In addition to protection I should be able to spot and isolate problems and rectify faults.

 

[Plum]

I presently have at least five different types of 12v fuse within a modest heritage electrical system.

For average circuits that do not involve self-contained pre-fused circuit boxes such as

ST Blade Fuse Block - 6 Circuits with Negative Bus and Cover - Blue Sea Systems

is it a practical target to just use blade fuses in a good waterproof holder like

GTIWUNG 10Pcs Car Inline Fuse Holder 32V, In-line Standard Blade Fuse Holder Waterproof 16AWG, Middle Fuse Holder Box, Medium Size DC Fuse Holder: Amazon.co.uk: Automotive

or are there any reasons to use different types such as a need for quick blow or slow blow fuses ? Are boat circuits (except radio ? ) capable of being sorted with one standard type of blade fuse of different ratings ? I would like to end up with a logical, tidy system with just one box of spare fuses, if possible.


signed Electrically Confused of Plymouth

If everything is wired and fused correctly then why bother to change anything just to commonise on fuse type? Just carry 5 different types as spares. You will probably never need them anyway if you have a good installation. I've never had a fuse blow in over 35 years.

Www.solocoastalsailing.co.uk

 

[awol]

[Pedant] There is no such thing as a 12v fuse - the poor wee things do not give a jot about the voltage but if you try and suck too much current through them they give up the ghost.[/pedant]

 

[Stemar]

I chucked the ceramic fuses out of Jissel a good while ago - I've spent far too long fighting them, their corrosion and bad contacts in old cars and bikes. I replaced them with blade fuses, which have simply done what they're supposed to.

I'm now doing the same for Jazzcat. The holders I got aren't waterproof, but they're probably in the driest part of the boat, so I'm not too bothered. What they do have is an LED that tells me if a fuse has blown. They also have labels. If you're doing a tidy up on your wiring, a label printer or some other simple system for identifying wires and fuses is a must.

 

[PaulRainbow]

I don't like 50,000 different fuse styles/types and i don't like fuses scattered all over the boat, some in random places that you can't find easily, if at all.

So, i stick to automotive blade fuses, where they are applicable, which is pretty much all of the sub 40a circuits. Any electronics that come with inline fuses have them removed. Where possible i keep all of the fuses in one place, or groups, depending on the boat size/electrical complexity. There'll typically be one or more fuse panels behind the switch panel, which obviously needs to be easily accessible. In some installations there will be "satellite" switch and/or fuse panels in other areas of the boat, perhaps one in forward or aft cabins of bigger boats, etc. There are odd occasions where an inline blade fuse is appropriate, but never clusters of them where a neat panel will fit.

Having 50,000 different fuse ratings is also a waste of time. Why have 2a, 3a, 4a, 5a when 5a will protect all of those circuits ? I tend to use 5a fuses for anything 5a and below, unless there are special requirements, which is rare, remember, you're protecting the wiring in most cases (circuits with pumps and motors etc are different). Then i use 10a for anything that needs >5 and <10. Not much on the typical boat that needs more than 10a, so there might be an odd 15a, 20a etc. but again, if several, pick a fuse that covers as many as possible.

Before anyone pops up and tells me that's crap, consider boats fitted with circuit breakers, or your shore power system with MCB's. These are only available in limited ratings, same as i described above for fuses.

Some installations that i do are almost exclusively protected by thermal circuit breakers, possibly with the odd inline blade fuse as above.

No method is totally suitable for every boat, so adapt to your requirements.

 

[JohnGC]

[Pedant] There is no such thing as a 12v fuse - the poor wee things do not give a jot about the voltage but if you try and suck too much current through them they give up the ghost.[/pedant]

If you look at fuse datasheets you will find that voltages are specified.

Voltage is important when the fuse blows. EG The gap created to open the circuit must not ark after the fuse has blown. The fuse will also ark while blowing but should not damage the fuse body or holder in doing so. Voltage is a key factor in this.

Littlefuse's ATOF mini blade fuses are rated at 32V. Making them suitable for use on 12V systems but marginal on 24V systems. Other blade fuses in Littlefuses' catalogue are rated at 58V.

 

[JohnGC]

Blade fuses are suitable for most dc powered things on a boat of fairly low power needs. Good quality ones are a must and not all fuse holders are made equally.

Circuit breakers can be a good idea for disribution as they are quickly reset.

Western electrical marine division is a good place to pick up these things (I assume your in plymouth uk from your last sentence!) No affiliation except for being a regular customer

Thanks for the pointer, they are handy for me too.

 

[pandos]

what they do have is an LED that tells me if a fuse has blown.

Have you sourced these.? I have seen them on a few sites but worried about quality and unnecessary complications?

 

[Sandy]

Big vote for blade fuses from me.

If you are passing Exeter or Plymouth BBL is my favorite fuse shop.

 

[Stemar]

Have you sourced these.? I have seen them on a few sites but worried about quality and unnecessary complications?

I just got mine from Ebay or similar. TBH, I can't say much for the quality, but they work and it takes a bit of a shove to put the fuse in, so there must be a decent contact.

One thing I'm doing is to have a supply line direct from the battery isolators going into the fuse box via one of the "outlets" fitted with a 20A fuse. The supply terminal then feeds a second fuse box via master switch, and the few things that aren't on the master switch are taken from the first fuse box via appropriately sized fuses. Ideally, the 20A fuse should be at the isolator end of the supply cable, but there isn't a convenient place for it, so this is better than no fuse.

 

[awol]

If you look at fuse datasheets you will find that voltages are specified.

Voltage is important when the fuse blows. EG The gap created to open the circuit must not ark after the fuse has blown. The fuse will also ark while blowing but should not damage the fuse body or holder in doing so. Voltage is a key factor in this.

Littlefuse's ATOF mini blade fuses are rated at 32V. Making them suitable for use on 12V systems but marginal on 24V systems. Other blade fuses in Littlefuses' catalogue are rated at 58V.

I stand corrected!

 

[thinwater]

In fact, if you are blowing more than one fuse every few years, there are system design problems. Blowing fuses or breakers is not a normal thing. It indicates serious overload.

 

[sarabande]

I agree with you, TW, but I have had one fuse blow in four years and that was due to my carelessness in waving the bare-ended wires of a new bilge pump between the terminals of two batteries. Pop, one 20 blade fuse went.

It's a mix of tidying up and adding a few new circuits for e.g USB charging, berth lights, and wanting to put fuse boxes into more accessible positions and to add indicator leds for key circuits such as pumps, radio, nav lights, etc., and to add a standard Anderson connector to each battery to provide flexibility of contingency power source . While doing that, I wanted advice on the possibility of having one type of fuse (standard blade) for the majority of circuits. Clearly, bigger fuses needed for main batteries and higher loads or where slow/quick blow are specified.

In the main, it's a tidying up and rationalising operation, not because the existing set up is inadequate, but because I have the opportunity to re-work some of the layout and put in a few new boxes.

 

[Stemar]

I agree with you, TW, but I have had one fuse blow in four years and that was due to my carelessness in waving the bare-ended wires of a new bilge pump between the terminals of two batteries. Pop, one 20 blade fuse went.

Me too. All the fuses I've blown - car, boat or home have been self-inflicted.

 

[Red Panda]

As I gradually rewire the boat, I'm standardising on blade fuses. I bought a big bag of them off eBay, loads of different colours, for a fraction of the cost of those wee blister packs in Halfords or wherever.