Cable sizing

[Sy-Revolution]

Hi Folks,
I'm due to start wiring up my new (to me) narrowboat. I bought her as an unfinished project and although much of the work has been completed the gas and leccy has not been done. The previous owner has fitted a number of flourescent lights and I plan to leave these in place but add some LEDs beside them. I have calculated that my total power consumption with all lights on will be around 125w each side of the boat, the run is 50 ft.
My system is 24v. By my reckoning I should be ok with 10mm² cable.

I'm new to inland waterways stuff and the BSS, would 10mm² be ok to run those lights over 50ft and would it pass BSS?

Any ideas?

Cheers,

C.

 

[VicS]

Do you mean 10mm² ?

10mm² has resistance of approx 2 ohms per 1000m

therefore 50 ft ( 15m) has resistance of 0.03 ohms (** see below)

volts drop at approx 5 amps is therefore 0.15 volt or approx 0.6% of 24 volt

Well inside the limit, even for a critical application like a nav light where 3% would be acceptable

**
The distance run should be the sum of the positive and negative wires so if thats a total of 100ft (30m) you will get double the above volts loss and still well inside any limit.

BUT
Did you mean 1.0mm²

If so multiply the above by 10.
1.5 volts, over 15m, is barely acceptable. 3 volts, over 30m, is probably not.

LEDs might be OK with that sort of loss but probably not the fluorescents

If you are talking about 30 m total ( positive + negative) then you should be looking at about 2.5mm².
But if its 15m total then 1.25mm² will do the trick

 

[Sy-Revolution]

Hi Vic, yes I meant 10mm² or 9 AWG.

Could I get away with 6mm² ??

Thanks for the reply.

C.

 

[VicS]

Hi Vic, yes I meant 10mm² or 9 AWG.

Could I get away with 6mm² ??

Thanks for the reply.

C.

AWG 9 is 6.63mm² according to my data

But see the last couple of lines I added to the previous post

 

[colhel]

My Uncle used to build narrow boats and one the biggest problems was corrosion caused by the electrical system. This was about 30 years ago. I don't know enough to offer advice, but just wanted to warn you.