Electrics, cable, amps

[Alan de Enfield]

Just now, Tony Brooks said:

As long as the cable meets the minimum strand number, which 28/0.30 does

 

But 28/0.3 is only 2mm2.

 

 

 

42 minutes ago, kellyjllek said:

 But I'd like to get the twined black and red in the black sheath as I'd be running it under the floor in the hull.

 

DO NOT DO THAT.

Not good practice and if you have any problems how do you get to sort out or repair the cable.

[Tony Brooks]

1 minute ago, Alan de Enfield said:

 

DO NOT DO THAT.

Not good practice and if you have any problems how do you get to sort out or repair the cable.

 

and it may fail the BSS. keep wiring as high as possible and as dry as possible,

3 minutes ago, Alan de Enfield said:

 

But 28/0.3 is only 2mm2.

 

 

but it is nominally around 14 amp cable so for typical bilge pump runs should be more than  adequate but the OP needs to work that out for himself with the run length.

[Alan de Enfield]

6 minutes ago, Tony Brooks said:

and it may fail the BSS. keep wiring as high as possible and as dry as possible,

 

I was going to say that but wasn't sure.

It is certainly a non-compliance as far as the RCD is concerned.

[Tony Brooks]

Just now, Alan de Enfield said:

 

I was going to say that but wasn't sure.

It is certainly a non-compliance as far as the RCD is concerned.

 

you will not by my careful words that I am not sure either, but  think it is and it is bad practice.

[Alan de Enfield]

I've looked at the BSS, and, as expected it does not go into such in depth detail, HOWEVER, it does state that any connections must be above bilge level

 

 

3.3.3 Are all electrical cable connections above bilge water level or suitably protected? R

Action : Check the position of all cable connections which can be seen.

Where cable connections are below bilge water level check for the presence of watertight enclosures marked as compliant with IP 67.

 

Requirement : All cable connections must be above bilge water level or be protected by a watertight enclosure meeting the IP 67 standard

[David Mack]

1 hour ago, Tony Brooks said:

To find the correct size of cable you need to calculate it to minimize the volt drop along its length.There are a number of online cable size calculators of you can use:

 

0.0164 x run length x current divided by the conductor cross sectional area.

 

Current in amps, length in meters and area is the conductor cross sectional area (CCSA) in sq mm. Aim for less than 1 volt of volt drop on most circuits and less than 0.5  volts on charging and starter circuits.

Although Tony mentioned it in his previous paragraph, for the avoidance of doubt, 'length' in this case is the total length of the circuit from battery to bilge pump and back to the battery - so twice the one-way distance.

Edited February 28, 2022 by David Mack

[ditchcrawler]

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