Help with simple wiring

[ribber]

I have replaced my four switch panel which had individual circuit breakers with a home made switch panel.
My thoughts were to keep it all dead simple, on/off with little joints, no circuit breakers etc..

I made up a Perspex panel and put in four waterproof toggle switches. I have the live feed with a waterproof 7.5 amp inline blade fuse onto the first toggle switch, then joining the other three toggle switches in series. I then decided to wire the anchor light, nav lights, deck light and manual side of bilge pump. I have not put in any waterproof blade fuses to any of these components.

All negative wires come back to a bus bar.

All works perfectly fine and was quite pleased with the outcome.

My problem being that if anything goes wrong, then the one and only fuse (7.5) will blow and all electrics will go out. Will/is this really such a problem.

Over the 13 years of having the rib, all my gremlins/problems with the electrics are not that the fuses have blown, just that the connectors have corroded or the circuit breakers have got wet or the bulbs bayonet fittings have corroded.

So have I gone too simple by just having the one fuse on the live feed?

[jwalker]

It depends on the quality of your other wiring doesn't it? Are you likely to get a short circuit anywhere? Personally, I'd like to see each circuit fused separately, an easy way to do this would be to pop an inline fuse of sensible value into each switch input or output and change out the main fuse for a higher rating one.

[Last Tango]

Originally Posted by jwalker

I an easy way to do this would be to pop an inline fuse of sensible value into each switch input or output and change out the main fuse for a higher rating one.

+1.
Keep it simple but fuse each item separately. Even without a "short" something as simple as the cut tail end of a cable-tie getting into the bilge pump can jam it, load up the motor and pull more than 7.5amps.

[simzpilot]

I guess if you knew how many boat fires were caused by short cuts in wiring you would probably think otherwise. Personally I dont take any shortcuts here as I dont fancy trying long distance swimming if anything goes wrong.

[ribber]

OK thanks for your help. I guess I've been too simplistic and will attach a positive bus bar and take individual waterproof inline blade fuses to each toggle switch. Then upgrade my live inline fuse to say 20amp.

Would this be reasonable/safe.

Thanks

[Seaflyer02]

If you are using blade fuses I would suggest getting the LED type off eBay, these light up when they blow. This makes locating the faulty circuit child's play.

[33JS]

Originally Posted by Seaflyer02

If you are using blade fuses I would suggest getting the LED type off eBay, these light up when they blow. This makes locating the faulty circuit child's play.

Available from Halfords too! I just installed a suite of them into an automotive box with clear perspex lid as a temporary measure.

[jeffstevens763@g]

Fuse Box With Common Power & Ground Buses 6-Way | 12 Volt Planet

Just doing mine and waiting for this to come so each item will be fused separately you can get them with LED warning light but no need for me you can see a blown fuse

[jwalker]

Originally Posted by ribber

....and will attach a positive bus bar ....

Would this be reasonable/safe.

Thanks

Personally I don't like positive buss bars simply because they are big and live! I'd let you off with a single pillar with eyelets on your fuse tails. If you can box it so much the better. If you're going for general purpose blade fuse holders, grease the blades well to seal them from moisture. Don't ask me how I know this to be a good thing!

[Bigtalljv]

Blue sea makes some cool breaker strips, breakers instead of fuses. I used those and really like it

[breezeblock]

Originally Posted by ribber

I have replaced my four switch panel which had individual circuit breakers with a home made switch panel.
My thoughts were to keep it all dead simple, on/off with little joints, no circuit breakers etc..

I made up a Perspex panel and put in four waterproof toggle switches. I have the live feed with a waterproof 7.5 amp inline blade fuse onto the first toggle switch, then joining the other three toggle switches in series. I then decided to wire the anchor light, nav lights, deck light and manual side of bilge pump. I have not put in any waterproof blade fuses to any of these components.

All negative wires come back to a bus bar.

All works perfectly fine and was quite pleased with the outcome.

My problem being that if anything goes wrong, then the one and only fuse (7.5) will blow and all electrics will go out. Will/is this really such a problem.

Over the 13 years of having the rib, all my gremlins/problems with the electrics are not that the fuses have blown, just that the connectors have corroded or the circuit breakers have got wet or the bulbs bayonet fittings have corroded.

So have I gone too simple by just having the one fuse on the live feed?

the other way of looking at it is if you have a few circuits that don't require a 7.5 amp fuse say your nav lights that may pull less than an amp its way too big a fuse I got caught out with this before with the bluesea 4 way switch panel the breakers are rated at 10 amps each I replaced some of them with a lower value more suited to the load

[ribber]

Thanks for replies and help.

From what was said, I've put the live feed with inline blade fuse 7.5 amp into a 5 way bus bar, then fed each individual toggle switch with a waterproof inline blade fuse from the bus bar. Nothing drawing many amps, so each fuse rated at 3amp.

All working ok and happy I've tidied up wiring with proper crimped and sealed eye connections screwed to switches and bus bar.

[Last Tango]

Originally Posted by ribber

. Nothing drawing many amps, so each fuse rated at 3amp.

Ok not sure what's on everything but your VHF might need a bit more, maybe 5amps when it's transmitting on Hi power and I'd check the bilge pump when it's actually pumping water.....might be a bit borderline at three amps depending on the size.

[jeffstevens763@g]

Originally Posted by Last Tango

Ok not sure what's on everything but your VHF might need a bit more, maybe 5amps when it's transmitting on Hi power and I'd check the bilge pump when it's actually pumping water.....might be a bit borderline at three amps depending on the size.

re radio mine needs 6 amp fuse

[ribber]

OK I have checked the amps for my bilge pump, Rule 500 and the rating is only 2 amps. Very low power so I think I'll be ok with the 3amp fuse. Lighting and nav lights the same. VHF runs off its own separate supply.

Not complicated just bloody awkward to get the wiring neat in restricted access, knowing you are going to have to get to it when the inevitable happens.

Rule-Mate Automatic Eco Bilge Pumps Specification

Rule 500
Length 153mm
Width 83mm
Height 114mm
Voltage 12v
Hose Connector 3/4" (19mm)
Output Up to 1890 litres per hour / 500 gallons per hour Up to 2840 litres per hour
Head 3.6m (12ft)
Maximum Amps 2 amps


Rule 750 / 750 gallons per hour
Maximum Amps 2.7 amps

[Lee1]

Personally I don't use breakers when it comes to 12v I use inline water proof blade fuse holders and I fuse each and every feed to any equipment separately.

[Pikey Dave]

Originally Posted by ribber

OK I have checked the amps for my bilge pump, Rule 500 and the rating is only 2 amps. Very low power so I think I'll be ok with the 3amp fuse. Lighting and nav lights the same. VHF runs off its own separate supply.



Not complicated just bloody awkward to get the wiring neat in restricted access, knowing you are going to have to get to it when the inevitable happens.



Rule-Mate Automatic Eco Bilge Pumps Specification



Rule 500

Length 153mm

Width 83mm

Height 114mm

Voltage 12v

Hose Connector 3/4" (19mm)

Output Up to 1890 litres per hour / 500 gallons per hour Up to 2840 litres per hour

Head 3.6m (12ft)

Maximum Amps 2 amps





Rule 750 / 750 gallons per hour

Maximum Amps 2.7 amps

Just as an aside, the primary function of a fuse is to protect the cable supplying the load, not to protect the load. A fuse should always be paired to an appropriately sized cable. The final fuse sizing should take into account the attached load, but not be dictated by it. E.g

Your pump is 2A, I'd be supplying that with 1.5mm tinned copper stranded cable, this is rated at 20A, I always de-rate by around 25% & use the lower figure(15A). The fuse should always be rated lower than the cable, but higher than the load. In your case, I'd stick a 5A fuse in there.
All IMO, other methods are available[emoji6]

[Last Tango]

Originally Posted by Pikey Dave

Just as an aside, the primary function of a fuse is to protect the cable supplying the load, not to protect the load. A fuse should always be paired to an appropriately sized cable. The final fuse sizing should take into account the attached load, but not be dictated by it. E.g

Your pump is 2A, I'd be supplying that with 1.5mm tinned copper stranded cable, this is rated at 20A, I always de-rate by around 25% & use the lower figure(15A). The fuse should always be rated lower than the cable, but higher than the load. In your case, I'd stick a 5A fuse in there.
All IMO, other methods are available[emoji6]

+1

If the fuses are just marginally above the expected load they'll run warm and you'll drop voltage across them.

[ribber]

Pikey dave Many thanks for that, will replace fuse as you say with a 5 amp. Easy to do, as now all separate. Would have liked to have one of those fuse boards, but access and existing wiring didn't allow.
Cheers for input