Switch panel fuse sizes

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Nicholas123

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Yesterday in order to try & use some current & get my voltage down I turned on every facility that my switch panel covers & had the vacuum cleaner running through a cigarette lighter socket but the fuse to the switch with a lighting indicator on the panel that I believe enables all the other facilities to be used blew. It had a 5 amp fuse in it (as has all the other provisions).
What should they really be,can anyone tell me?
 
Nicholas123 said:
Yesterday in order to try & use some current & get my voltage down I turned on every facility that my switch panel covers & had the vacuum cleaner running through a cigarette lighter socket but the fuse to the switch with a lighting indicator on the panel that I believe enables all the other facilities to be used blew. It had a 5 amp fuse in it (as has all the other provisions).
What should they really be,can anyone tell me?
Click to expand...

Each fuse should be slightly larger than the load on the circuit it protects ......... AND the wiring of each circuit should not only have a safe working current rating greater than the fuse rating but should be oversized to avoid unacceptable volts drop where voltage sensitivity would be a issue.
Some equipment, with a high start up current, may require a slow blow fuse.

If you are saying that the fuse that has blow is a main fuse protecting all the circuits then in must be rated to carry the max total current that might be expected... The wiring within the panel should be rated with this in mind.


I would expect your vacuum cleaner to draw significantly more than 5A ......... Read the instructions ........ mine takes 10A
 
Mines a little LIDL vacuum cleaner & in the manual all it says is that it is 12 volts & 120 W but I get the drift here. The vacuum cleaner turns on without having to flick a switch on the main instrument panel so I suppose that can be taken out of the equation. Which just leaves the load from the main facilities to be taken into consideration ( Masthead light. Steaming light. Spreader light. Deck navigation lights. Interior & compass ) so when all totalled up I presume the main panel switch with red indicator light would have to have a fuse size in there greater than all the rest combined (supposing that I can calculated what all the rest if on would consume). :ambivalence:

There is also a block containing several fuses of far bigger rating right next to the panel bank that feed into it which must additionally protect the whole shooting match ( + several others dotted about the boat ) so this ai'nt just a simple matter.

Thanks Gents. Slowly slowly I am learning & my boat is being tamed :D
 
VicS said:
Time spent drawing up a wiring diagram could be time well spent,
Click to expand...

It would certainly be handy.The problem seems to be that lots of stuff has been added over the years mainly on the Continent since that is where it was directly exported to upon manufacture.
It all just looks like a hornets nest at the moment but I expect I'll get round to it eventually........if I live that long :D
 
When you total up the mast head tri colour ( not that that seems to have been working recently ) + the steaming light ditto.The spreader light that I know has been working recently & the deck bow combined port & starboard + stern light that I also know works.That's it! & that is just about 3 bulbs for sure of the 12v 22/25 watt variety so that dos'nt seem like much of a heavy load. All I have got to do is total up the amperage (however you do that ) make sure the main enabler on the switch panel has a fuse in it of a higher amperage than the lot combined?
Some forward cabin lights could have fed into the equation but were not on when the fuse blew. Anyway,total amperage of all utilities combined + say one amp for a security margin?
 
Nicholas123 said:
It would certainly be handy.The problem seems to be that lots of stuff has been added over the years mainly on the Continent since that is where it was directly exported to upon manufacture.
It all just looks like a hornets nest at the moment but I expect I'll get round to it eventually........if I live that long :D
Click to expand...

You will save yourself a shed load of time to rip it all out and start again, sanely this time.
Draw up the system you want and build it on a clean slate. if you dont then you will need to be a master craftsman wireman to not end up with another hornets nest/rats nest/bowl of spaghetti.

Invest in enough cable so it is all clipped to something in nice straight runs, you would do well to get some cable tray (preferably pvc). If there are runs behind panelling then put in trunking or conduit with a permanent draw wire in.
 
If you have three navigation lights each drawing 2 amperes, totalling 6 amperes and they are all supplied through a single, 5 ampere fuse then I would expect the fuse to blow. Even if one light is not working you only have one ampere available for anything else on the circuit.
 
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