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Old 28 July 2011, 07:40   #31
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Regardless of whether they are available through Sowester or not,
They went bust 10 years ago

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And finally, there is no such thing as a current rating for a cable unless you know how long it is. The maximum current it will take depends on it's length and also whether it is enclosed, bundled with other cables or open to the air to dissipate heat.
Erm, I've always consulted this....
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Old 28 July 2011, 08:07   #32
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There's some very useful info to be found here as well....

http://www.aquafax.co.uk/pdfs/08a_cat.pdf

Interesting how a tinned wire is rated higher than plain multi strand copper.

I try to only use tinned on all my jobs, but find it interesting that most electrical equipment, engine looms etc are nearly always un-tinned multi copper, although they sometimes dip the ends in solder, which to me is wrong. Seen wiring fail from breaking at the soldered end.
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Old 28 July 2011, 08:14   #33
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So to be future proof bearing in mind that all will probably ever be running from the new BEP fuse panel will be a nav light, VHF radio and chartplotter what mm^2 (tinned) cable should I be running from the battery to the fuse panel?
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Old 28 July 2011, 08:34   #34
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Erm, I've always consulted this....
You obviously understand I2R and hysteresis losses. Perhaps you'd like to give the national grid your check sheet and tell them that they needn't ramp up their distribution voltages to overcome current limit capability of cable over long distances.
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Old 28 July 2011, 09:12   #35
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You obviously understand I2R and hysteresis losses. Perhaps you'd like to give the national grid your check sheet and tell them that they needn't ramp up their distribution voltages to overcome current limit capability of cable over long distances.
Whilst you may very well be technically correct, I think you are completely missing the point. It needs to be fit for purpose, and if you are changing conductor sizes dependent on a 4m rib compared to a 9m rib,and cable installation technique then you are trying to make electrical installations a black art which it is not. I have yet to see a "quality" installation by anyone in the small boats "marine electrical industry" and while I haven't seen them all I have looked at a lot.

Poor guy was just asking for some PRACTICAL advice, next we should start to debate Einsteins theory or relativity...

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Old 28 July 2011, 09:18   #36
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So, what cable to go to the fuse box from the battery?
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Old 28 July 2011, 16:55   #37
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You obviously understand I2R and hysteresis losses. Perhaps you'd like to give the national grid your check sheet and tell them that they needn't ramp up their distribution voltages to overcome current limit capability of cable over long distances.

Actually, yes, I do, but I think your losing sight of the fact that this is only a little boat.

Dunno what you do for a living but I suspect your a bit of a jobsworth!
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Old 28 July 2011, 17:03   #38
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Assuming your battery is about 1m away (i.e. total return cable length of 2m) and you want less than 3% voltage drop for your equipment then I would suggest 4mm2 as being suitable. This also assumes that ultimately you will draw no more than 20A off your fuse panel. 3A for nav lights, 3A for GPS and 8A for VHF with an arbitrary 6A capacity left over for future gadgets. If your battery was 3m away you would need 8mm2 cable as 4mm2 woudl only give you 15A before voltage drop becomes an issue.

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Dunno what you do for a living but I suspect your a bit of a jobsworth!
Far from it. Nothing riles me more. What does though, is people asking for advice and only being given half the story. More like trying to be a perfectionist rather than a jobsworth.

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Poor guy was just asking for some PRACTICAL advice,
I did give him practical advice. I told him to get a BEP or Bluesea fusebox. I've also just told him what cable size to use.

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next we should start to debate Einsteins theory or relativity...
We'll leave that to Gotchiguy I think
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Old 29 July 2011, 03:38   #39
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Thanks Erin. I have ordered 4m of 4mm^2 tinned cable in both red and black as well as a Blue Sea fuse box with negative bus bar.
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Old 29 July 2011, 04:15   #40
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Well I might as well round it off to 30 posts but you got the best end result in the end. It should be something less to worry about when you've done

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