Fuses on distribution panel.

[Dirk Diggler]

Originally Posted by maxhar

. I will be connecting a radio with 7.5amp inline fuse to here, will these distribution fuses cause any problems?

Originally Posted by Pikey Dave

If I'm reading the photo right, they're 8A fuses x 4 = 32A max possible load fed, via what looks like a 1.5mm2 length of cheap flex. Corrosion might be the least of his worries.

I'm sure if he's only connecting a radio, 1.5mm will be fine, should be good for 8 or so amps. Would probably best to stick at that though, or get an auto extinguisher.

[rigi36]

The 1.5mm^2 cable is rated at 21 amps. I am connecting a VHF that at most draws 6.3 amps. I don't see a problem.

[Pikey Dave]

Originally Posted by maxhar

The 1.5mm^2 cable is rated at 21 amps. I am connecting a VHF that at most draws 6.3 amps. I don't see a problem.

That's why you were advised to get professional help the last time you raised this subject, that's me done. Should he require further advice, I refer the honourable gentleman to the signature line below.

ee lad, tha can't educate pork

[rigi36]

Well it was a professional boat builder who put in the 'dodgy' fuse box.

[Dirk Diggler]

Originally Posted by maxhar

Well it was a professional boat builder who put in the 'dodgy' fuse box.

Originally Posted by maxhar

The marine dealers that installed the outboard put it in, I would have thought they knew what they were doing.

rare to find a "marine dealer" who is also a "professional boat builder"

You've asked for advice, been given it, up to you if you wanna take it

[Searider]

"Hella" type fuses.

Used on almost every boat built in the 1970s and 1980s.

Yes, prone to corrosion on the ends of the fuses - but if being used on the non-salty Thames will be fine with regular inspection / cleaning.

Rating indicated by colour and moulded into the plastic body of the fuse (Not ceramic as stated above).

The original question was "will it be ok to connect a VHF with an inline 7.5A fuse to these?"

Answer: Yes

[9D280]

When wiring my panel I looked at one of these (on sale in a Chandler's). Reason I didn't? I couldnt find small enough rated fuses to put in it!

Now have an enclosed (supposedly) watertight minature slot type.

[Erin]

Regardless of whether they are available through Sowester or not, they are pretty low down the quality list for boat use IMV. No matter how dry you think your console is, it is unheated and pretty much unventilated. It will get damp through condensation and that will be enough to cause corossion on the ends. Don't call us for help when your VHF stops working (oh... just realised you won't be able to )

There are countless people that consider themselves professional in the boating community. Just because they call themselves it certainly doesn't mean they are. If they don't understand tinned cable and reliability in electrical work then I would steer clear. Sadly alot of this type of problem is down to ignorance and the remainder down to cutting costs. Listen to Cookee - we can vouch for his experience. Perhaps you will question how professional your fitter is when you understand that 8A is twice the current your average set of nav lights would take.

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.

Get yourself a BEP or BlueSea panel which will be made with stainless steel contacts and take modern automotive fuses. You can then fit and forget.

[rigi36]

Ok, based on the advice here I am going to remove the current block and supply cable and replace with this:

Circuit / Switch Panels, Bep Atc Fuse Holder 6 Way Screw Terminal from EC Smith UK Marine Supplier

and 4mm^2 Tinned cable.

Does this look like a better solution?

[Jizm]

Originally Posted by maxhar

Does this look like a better solution?

Yes, better than what you have.

[Dirk Diggler]

Originally Posted by Erin

Regardless of whether they are available through Sowester or not,

They went bust 10 years ago

Originally Posted by Erin

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....

[Dirk Diggler]

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.

[rigi36]

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?

[Erin]

Originally Posted by Dirk Diggler

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.

[Crusher]

Originally Posted by Erin

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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[rigi36]

So, what cable to go to the fuse box from the battery?

[Dirk Diggler]

Originally Posted by Erin

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!

[Erin]

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.

Originally Posted by Dirk Diggler

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.

Originally Posted by Crusher

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.

Originally Posted by Crusher

next we should start to debate Einsteins theory or relativity...

We'll leave that to Gotchiguy I think

[rigi36]

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.

[biffer]

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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