Fans on light circuit?

[Djarraluda]

As Autumnbreeze noted, the calc will define if you have an issue.
Re the overload of a sub-circuit, yes, it should be checked but not generally much of an issue as the loads are not that high. As an example, a 10A load will be OK inmost fittings we use so even though we have several 2 or 3 A loads on the circuit, the cable and joints are all OK for the 10 anyway. It gets more critical if you have 20A or greater circuits, because many switches etc are not rated that high and we could get a 10A switch on a 2A light all on a 20A circuit - yes, the fittings are then at risk.
It is safer with fuses than most CBs because the fuse blows quicker and the best is to fit an in-line fuse with adequate discrimination.
Sketch out a single line diagram of each circuit and check the fittings and loads there.
It is a good way to record your wiring and you get to see what is where in the manual then.

One of the many ideal key things with the selection of how many circuits, is to attempt to get the fuses the same in the panel. Do not have a 5A next to a 2A, next to a 15A and so forth, because it will get messed around over the next few years when the fuse blows but you only have a bigger one on-board as a spare

[David B]

Hello Ronnie,


In response to your question, there are a couple of answers, and both are correct.
First up, my background is electronics (qualified). I have re-wired a small 30 year old yacht we have, and have also added to the wiring of a new yacht we have.


As you mention you are re-wiring your yacht, for me the best option is a separate circuit for the fans - not because it is needed, but because it is good practise and it can be useful in future to be able to isolate at your panel, the lighting circuits from the fan circuits. No need to go overboard in this though. A single 'FANS' circuit, or as you have two lighting circuits, you could stretch that to 'FANS FWD' and 'FANS AFT' circuits, is all that I would suggest.
So that's in my view the ideal, and as you are re-wiring, it should not be too much of a big deal to run those extra circuits.


On the other hand, with our new boat, I have not done this. With our new boat, there is a spare switch on the panel that I could allocate to fans, but frankly, there are enough things taking up my days onboard, so I have adopted the pragmatic approach. The wiring to all lighting circuits is plenty adequate for the LED lighting we have onboard and then some. The fans we have installed draw less than 1 amp each, and therefore (especially as the fans are located close to lights in each case), I have just tapped into the un-switched side of lighting circuits for the fans in each aft cabin, the two fans in the owners cabin, the fans in the galley, and the dining areas. With all lights on, and all fans running, there is plenty of safety factor, and all circuits are protected by MCB's or fuses.


So there you have it - ideally (and as you are pulling new wires anyway) separate, but otherwise, (unless you have all the time in the world), don't get too hung up on it.
As a note, I did a fair bit of research into fan types, and for us the Caframo Bora was the best choice for the cabins (compact, reasonably quiet, reasonable air-flow and aesthetic), while the (significantly better but also larger) Caframo Sirocco was ideal as a portable (made up a small base wrapped in vinyl to match the cabin interior) fan for use at the nav station and over in the dining area.


I hope that helps Ronnie.

[SailRedemption]

Originally Posted by autumnbreeze27

Separating the circuits has a few advantages. More control at the panel, if something happens to the fan circuit the lights still work, and vice versa. Disadvantages are cost and weight, and taking an extra spot on your dc panel.

Originally Posted by Djarraluda

As Autumnbreeze noted, the calc will define if you have an issue.
Re the overload of a sub-circuit, yes, it should be checked but not generally much of an issue as the loads are not that high. As an example, a 10A load will be OK inmost fittings we use so even though we have several 2 or 3 A loads on the circuit, the cable and joints are all OK for the 10 anyway. It gets more critical if you have 20A or greater circuits, because many switches etc are not rated that high and we could get a 10A switch on a 2A light all on a 20A circuit - yes, the fittings are then at risk.
It is safer with fuses than most CBs because the fuse blows quicker and the best is to fit an in-line fuse with adequate discrimination.
Sketch out a single line diagram of each circuit and check the fittings and loads there.
It is a good way to record your wiring and you get to see what is where in the manual then.

One of the many ideal key things with the selection of how many circuits, is to attempt to get the fuses the same in the panel. Do not have a 5A next to a 2A, next to a 15A and so forth, because it will get messed around over the next few years when the fuse blows but you only have a bigger one on-board as a spare

I actually had a diagram and I left a hatch open and rain washed the ink off. I won't be doing another one till I'm done. Haha, ain't nobody got time for that!

Originally Posted by David B

Hello Ronnie,


In response to your question, there are a couple of answers, and both are correct.
First up, my background is electronics (qualified). I have re-wired a small 30 year old yacht we have, and have also added to the wiring of a new yacht we have.


As you mention you are re-wiring your yacht, for me the best option is a separate circuit for the fans - not because it is needed, but because it is good practise and it can be useful in future to be able to isolate at your panel, the lighting circuits from the fan circuits. No need to go overboard in this though. A single 'FANS' circuit, or as you have two lighting circuits, you could stretch that to 'FANS FWD' and 'FANS AFT' circuits, is all that I would suggest.
So that's in my view the ideal, and as you are re-wiring, it should not be too much of a big deal to run those extra circuits.


On the other hand, with our new boat, I have not done this. With our new boat, there is a spare switch on the panel that I could allocate to fans, but frankly, there are enough things taking up my days onboard, so I have adopted the pragmatic approach. The wiring to all lighting circuits is plenty adequate for the LED lighting we have onboard and then some. The fans we have installed draw less than 1 amp each, and therefore (especially as the fans are located close to lights in each case), I have just tapped into the un-switched side of lighting circuits for the fans in each aft cabin, the two fans in the owners cabin, the fans in the galley, and the dining areas. With all lights on, and all fans running, there is plenty of safety factor, and all circuits are protected by MCB's or fuses.


So there you have it - ideally (and as you are pulling new wires anyway) separate, but otherwise, (unless you have all the time in the world), don't get too hung up on it.
As a note, I did a fair bit of research into fan types, and for us the Caframo Bora was the best choice for the cabins (compact, reasonably quiet, reasonable air-flow and aesthetic), while the (significantly better but also larger) Caframo Sirocco was ideal as a portable (made up a small base wrapped in vinyl to match the cabin interior) fan for use at the nav station and over in the dining area.


I hope that helps Ronnie.

Thanks for the information and experience friends. I have decided that I will have the fans on their own breaker switch, for a few reasons. As Autumn and David have stated, it's nice to be able to turn fans or lights off without affecting the other. I have extra circuits, and I have the wire.

David regarding the fans, I bought a camframo 757 and a hella turbo 2.0 to see which I liked better. I'll likely put a couple Hellas in the salon and camframo everywhere else. The lights are Imtra Auckland LED lights for the reading and I'll use replacement LED bulbs from marinebeam for the domes.

I appreciate all the insight and info on what is common practice.

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[David B]

Good decision Ronnie, and you chose the right panel there also (I also used a BlueSeas panel for my re-wire and was - and continue to be - impressed by the design and build quality). Those illuminated labels are a very nice touch also.
Caframo 757 - I have to say, I didn't like them at all. If you have a look at the Bora and the Sirocco, you will see why.
Good luck with the re-wire, and perhaps you can let us all know how it turns out in the end (what's the boat by the way ?
David

[SailRedemption]

Originally Posted by David B

Good decision Ronnie, and you chose the right panel there also (I also used a BlueSeas panel for my re-wire and was - and continue to be - impressed by the design and build quality). Those illuminated labels are a very nice touch also.
Caframo 757 - I have to say, I didn't like them at all. If you have a look at the Bora and the Sirocco, you will see why.
Good luck with the re-wire, and perhaps you can let us all know how it turns out in the end (what's the boat by the way ?
David

I'll check out those fans too, I only bought one of each for now to see them in person. Yea I'm excited to turn everything on and see the panel in action. It really is a solidly built item, I'm impressed thus far at the quality.

I'll definitely check back with an update on it all. The boat is a Kaufman 47.



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[David B]

Nice solid looking boat - thanks !