Who has checked their switch panel for correct fuses etc.

[Sailingsaves]

E.g. , one can buy a switch panel from Pacermarine on ebay or wherever, BUT it may come with circuit breakers of 5A and increasing up to 20A.

http://www.ebay.co.uk/itm/2-MARINE-...641135?hash=item2ca8fbe3af:g:EToAAOSwWTRWzzl4

Fused version:
http://www.ebay.co.uk/itm/MARINE-6-...333970?hash=item2ca85e9d52:g:JdAAAOSwG-1Wuw6T

The first link to the panel with circuit breakers would be no good to a low budget sailor such as me (no anchor windlass etc) , because no circuit I run needs over 5Amps, so I'd have to swap out all the higher rated circuit breakers.

A fused panel is easier to fix (if you carry a lot of fuses and tools to find problem BEFORE chucking in another fuse), BUT my question is, who has NOT checked that they have the correct fuses in there panel? (especially if having changed over to LEDs).

I found a friend's panel with 6Amp fuses on a circuit that draw less than 0.25 Amps for example.

There are many on here that are expert at 'everything', but there are some sailors perhaps that can sail and don't even know what a multimeter is.

Having said that, electronics and the sea don't mix well (as the film about poor old Donald Crowhurst may show if it corresponds to the book), but electronics do make life luxurious (if you treat them safely)

 

[Malish]

I have always worked on the premise that the fuses are principally there to protect the wire so even if the draw is only 0.25A I would still have a 5A fuse if that was applicable to the wiring.

 

[David2452]

I have always worked on the premise that the fuses are principally there to protect the wire so even if the draw is only 0.25A I would still have a 5A fuse if that was applicable to the wiring.

Hopefully without incident you have been working to an erroneous premise, an over current device is there to protect the circuit downstream of it which the cable is only a part, a device that is part of the circuit may have: lighter internal cable, windings and other parts more delicate than the cable and it should have appropriate overcurrent protection.

 

[savageseadog]

I have always worked on the premise that the fuses are principally there to protect the wire so even if the draw is only 0.25A I would still have a 5A fuse if that was applicable to the wiring.

I sort of agree with that. The wiring should be as thick as possible within reason, you need to have a circuit fused so it will blow before the cable melts so the thicker it is there's a reduced probability of sustained fault currents. However, it's still a good idea to fuse to suit the load because the device at the end of the cable could short, a motor such as in a pump can stall and develop currents large enough to set fire to it and potentially not blow a fuse.

 

[pmagowan]

Not sure I understand. My 'fuses' are based on my wiring and each device has its own protection for its internal wiring. I don't base my fuse on the current load as that might change.

 

[Sailingsaves]

Yes, my take is similar, have the best and thickest cable necessary and practicable.
But say you have acquired an old boat with (non-corroded) 10 amp cable, and it leads to a light that used to be a filament bulb but has now been replaced with a 0.25Amp LED, (without doing the voltage drop sums etc), I'd replace whatever fuse was in there with a 1Amp fuse and see how things go.

If a good LED, it will not heat up and no resistance will increase.

The 10 Amp cable carrying less than half an Amp is well protected with a 1 Amp fuse.

But unless someone has checked, the circuit could be on the Pacer marine type of board and wired to the 20A circuit breaker without thinking and that is potentially dangerous of course.

 

[Sailingsaves]

Not sure I understand. My 'fuses' are based on my wiring and each device has its own protection for its internal wiring. I don't base my fuse on the current load as that might change.

I base my fuses (well when I had a boat) on the max current load expected in the circuit (excluding a short obviously which is when I expect the fuse to do its job). Hopefully post 6 makes more sense of what I am trying to explain - some people not having the correct protection.

 

[pmagowan]

I base my fuses (well when I had a boat) on the max current load expected in the circuit (excluding a short obviously which is when I expect the fuse to do its job)

Bottom line is it should be on the right side of protecting the wiring. It shouldn't matter much what the load is if the 'fuse' protects the wire. If you are using a very small load then it is fine to have a small rated fuse because it will protect the wire anyway. However, the load is not that important as long as the smallest wires in the circuit are protected. Often this is done by the main wiring being fused and then the electronic device having a fuse for its own internal wiring. That is my understanding, it could be wrong.

 

[Lon nan Gruagach]

Not sure I understand. My 'fuses' are based on my wiring and each device has its own protection for its internal wiring. I don't base my fuse on the current load as that might change.

This is the best practice system. The cable is protected, devices sort themselves out.
Why?
For a simple circuit such as: source - wiring - single load it is fine to protect the load with the fuse at the distribution.
But...
What if you have 2 lamps on one lighting circuit and you unplug one lamp? Do you change the fuse while that lamp is removed so the other lamp cannot draw twice its rated current before blowing the fuse? NO, you dont.

I think what people are trying to do is protect broken equipment, its broken, its too late. What is important is the failure mode of the equipment.
Consider the new LED lamp on a circuit that used to have incandescents. The new lamp develops a fault, a short somewhere inside. You might just (almost impossible) fuse the circuit so that that is the limit of the damage to the LED. What really happens is that the over current condition vaporises the internal wiring ending up with an open circuit. There would be no point saving the broken (short circuit LED) from further harm. Devices are designed not to have dangerous failure modes , they break safely.
Lamps go open circuit, motors (darned well ought to have) over current protection such as thermal cut outs, electronic devices have fused power inputs.

And another thing:
It is best practice for the protection device nearest upstream from the fault to trip, that way fault finding is simpler.
If you extend the fuse for the device load principal back up the distribution system, you would fuse the input to the distribution at the maximum possible load (everything on) since any more would be a fault. Due to the nature of fuses then you can easily blow the main fuse with a sum of minor over current events that wont blow any downstream fuses. so where do you start looking for a fault... somewhere in the perfectly ok distribution panel... wrong place!

 

[Sailingsaves]

For a simple circuit such as: source - wiring - single load it is fine to protect the load with the fuse at the distribution.
But...
What if you have 2 lamps on one lighting circuit and you unplug one lamp? Do you change the fuse while that lamp is removed so the other lamp cannot draw twice its rated current before blowing the fuse? NO, you dont.

Getting a bit away from what I hoped was a simple post.

Friend had 10 Amp cable and 20 Amp fuse in panel powering 3 lights.

I replaced bulbs for 3 LEDs each drawing 1 Amp (very bright).

I fitted a 4 Amp fuse in his VERY old distribution panel. Backwards is of course a fuse to the panel and then a fuse at the battery.

If he uses 1 LED 1amp is pulled.

Max pull should be 3Amp unless something goes wrong and 4 amp fuse blows.

 

[Baggywrinkle]

Getting a bit away from what I hoped was a simple post.

Friend had 10 Amp cable and 20 Amp fuse in panel powering 3 lights.

I replaced bulbs for 3 LEDs each drawing 1 Amp (very bright).

I fitted a 4 Amp fuse in his VERY old distribution panel. Backwards is of course a fuse to the panel and then a fuse at the battery.

If he uses 1 LED 1amp is pulled.

Max pull should be 3Amp unless something goes wrong and 4 amp fuse blows.

Just one point, if you reduce the fusing based on LED lighting and an LED goes pop, then replacing the broken LED with an incandescent (perhaps because that's all you have at the time) will then pop the fuse meaning no lights at all. The fuse protects the wiring to prevent fires should a short occur either in the wires or the device interface, and isn't rated based on the technology you plug into the circuit.

If the circuit is capable of delivering 10A safely to the device, then fuse it for 10A ..... the device as said earlier, should fail-safe and go open circuit - it's toast anyway when it fails and could (in theory) draw a normal current but still set fire to itself internally - that's why devices are usually designed to fail safe and should look after their internal circuitry themselves.

 

[Sailingsaves]

Just one point, if you reduce the fusing based on LED lighting and an LED goes pop, then replacing the broken LED with an incandescent (perhaps because that's all you have at the time) will then pop the fuse meaning no lights at all. The fuse protects the wiring to prevent fires should a short occur either in the wires or the device interface, and isn't rated based on the technology you plug into the circuit.

If the circuit is capable of delivering 10A safely to the device, then fuse it for 10A ..... the device as said earlier, should fail-safe and go open circuit - it's toast anyway when it fails and could (in theory) draw a normal current but still set fire to itself internally - that's why devices are usually designed to fail safe and should look after their internal circuitry themselves.

Hopefully the 5 of the 17 people (that voted) and have not checked their fuses will now do so and measure the diameter of their wire.

The post was to find out who didn't check their panels (and run 6 amp wire via a 20 A circuit breaker) and hopefully alert such people. I now have a Pacer marine panel with only two 5 amp circuit breakers. All the other circuit breakers will have to be replaced. In fact, I may sell it (and tell people its set up) and build myself a bespoke panel (with my 3D printer) and decent switches, LEDs, circuit breakers and / or fuses, with some nice graphics etc (just for the heck of it - as a challenge to build the best panel going - I will then move onto eradicating the stupid indicator lights on modern cars that are difficult to see, knock out the daylight running light just to confuse you a bit more - I'll need good luck with that one - why they can't just stick the indicator lights WELL away from the bright brake lights etc is pee'ing me right off - form over function imo). I have just acquired some switches that will allow me to push it down to turn on white interior lights, or press it up, for all red (just for fun mostly. There will be other options of course.

My opinion is that everyone that goes to sea should be self reliant and be able to fix their own things (even down to a small bit of first aid), and hopefully no one would stick a filament bulb in a fitting that did house an LED.

The reason I am so safety conscious (or anally retentive) is that I have been on boats where horrible wiring has been evident.

Not all devices have fuses to protect them (fans - cooling types - e.g.).

I stick in-line fuses into such devices to protect the device, stop it from damaging the wire and ensure the distribution panel is set up correctly to protect the wiring - I don't trust the 'fail open' and prepare for the worst and hope for the best - "train hard, fight easy".

I always take a few steps towards the side of safety (4A fuse - or a slow blow 3A fuse if I am really worried about 3 1amp LEDs - or maybe a 3A circuit breaker - to protect 10A wire with a total load of 3A opposed to a 10 Amp fuse for the wire).

My first boat simply had nav lights, vhf and echo sounder and that was enough for me way back then.

 

[David2452]

Not sure I understand. My 'fuses' are based on my wiring and each device has its own protection for its internal wiring. I don't base my fuse on the current load as that might change.

Then you are doing it correctly, each circuit has downstream overcurrent protection, larger suited to the cable and smaller suited to the lighter load of the device. e.g. a heavy fuse for cable far to large for the device but designed to mitigate voltage drop and or supply multiple devices and a smaller one at the interface where lighter cable and components join that cable,