how to wire a narrowboat – part 3

how to wire a narrowboat - part 3

the sockets, pumps etc.

It is time to repeat the process for the sockets pumps etc., starting with the layout drawing.

Again the process is the same process as the one for the lighting drawings, a blank outline and put the pumps, USBs, 12 Volt sockets etc on to the drawing.

Outline for Power Sockets etc

First the symbols chart and an explanation of each item the USB outlets, Cigar Lighter etc are I expect apparent what is not is the Wago. They are a modern version of the old chocolate block and a lot better. When wiring things like the USBs etc they can either be wired with one cable all the way back to their own individual fuse or the supply cable can be broken where each USB etc is to go and the supply cable broken and joined to run on to the next one.

The Wago is the modern equivalent of the chocolate block connector but a 100 times better and unlike the Chocolate Block it does not damage the strands of the cables. It is also easier to fit, prepare the wire, lift the orange clip, slide the wire in, and push the orange clip back down job done. They cannot come open pushing the clip down locks them.

I have done the example drawing using them as using them as it makes big savings on cable.

So starting with the USB charging points the basic drawings looks like this:

Now using the 1 metre marks on the outline work out the cable runs length and then calculate the Volt Drop and from that the cable size, add the cable labels and you end up with a drawing like this:

The drain and water pumps:


The Drain Pump and Water Pump the negative cables are the same length as the positive

The 12V sockets – the negative cables are the same length as the positive cables.

This is divided into three circuits to keep the volt drop down to acceptable limits:

Now the Fridge circuit

Remember the general rule for fridges 1mmsq for every metre as the cable goes from the battery to the Fridge. Most fridges will start at 11V at 15A that is an average start up current so if there is a volt drop of 0.75V the fridge will start at 11.75V at the battery.

And finally the Cigar lighter circuit

Now you should have a complete set of circuits from them it is possible to calculate the amount of each type and size of cable needed the size and number of fuses and a diagram to do the wiring from and all of this can be done before the boat has been delivered with the aid of the outline plan supplied by the builder as part of their normal paperwork to clients.

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About Graham Mills

I have owned boats since I was 10 and have helped other boaters with their electrics for almost sixty years. I sold my last boat in October 2016 as I can no longer singlehand a boat. The result is more time to help others and that has expanded. I have never charged for my help, although now a days as a pensioner I ask boaters to pay my expenses to get to them which can be anywhere in the UK.