Circuit breakers and/or fuse panels

[Driftwood]

I am just about to purchase a circuit breaker switch panel for my boat.

Is it necessary to have both a circuit breaker panel and a fusebox within a house bank set up?

 

[tr7v8]

No it isn't in fact it's bad practise. It should be a main fuse to protect the cable from the battery and then the CB or Fuse.
You either have one or the other, if you can afford it go for the CB option as they are better. However if you must go fuses get continental style ones as they makea more reliable contact than some of the cartridge ones and are easier to get.
I'll add that normally it's the fuses that go with the switches, so if you have anything that isn't on the switch panel you'll need a fusebox for that.


Jim

 

[spannerman]

If the electrics can suffer from dampness definitely don't get the ceramic type as manya time we have found that the fuse appears intact, but in fact the end caps have a habit of corroding away while leaving the fusible section looking OK, ask anyone who had an old Volvo 240! you have to physically remove them to check them, go for either sealed glass ones or blade type fuses.

 

[Driftwood]

Thanks for the reply. I beleive you are right.....but I need to now explain my logic so the whole plan can be corrected where necessary.

I'll explain what I was thinking....I was planning a 4 way circuit breaker, going to Nav. lights, instruments, autopilot and house lights.....

The house lights I wanted to send to another switch panel (with fuses). These would be split to:

- mast light
- anchor light
- coach
- heads

I intended this because I read that every appliance (every light) ideally should have its own wire and fuse (?). i cannot get circuit breakers below 2 amps so i figured a fused switch panel for the lights would be best.

Now....slam me down if my electric knowledge is too ignorant, but my mast light is running 8w which means I require a 1 amp fuse.

If this is wrong, how wrong will determine if a professional comes in to do this.

/D

 

[bedouin]

As a general rule, fuses and circuit breakers are sized according to the wire between them and the load, rather than the load itself. So if the wire to your masthead light is rated at 5A then it is correct to use a 5A fuse, even if the lamp itself only draws 1A.

In most boats, the size of the wiring is determined by the acceptable voltage drop, rather than the load capacity of the wiring. I think the smallest fuse I use on my boat is 5A, I don't imagine that you will need to go any smaller than that (except maybe for electronics).