Suitable cable for wiring?

lesweeks

lesweeks

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At some time in the future I'll be wiring, from scratch, the gaffer that I'm restoring. The cable that I've stripped out is little more than bell wire and from what I've read I know that to be totally inadequate to handle possible current flow. Other than engine starting I envisage nav lights, panel displays (including sounder and log), radio, bilge pump and some lighting (oil lamps most of the time) to be battery powered devices. I've been given a drum of 1.5mm sq (16 AWG) black cable which I'd like to use for the DC return. So the question is whether this will be up to the task or do I need something larger?
 
When I rewired my old ketch, I used automotive cable. This is available in a variety of thicknesses to suit the various applications. There are also a range of colours in the insulation, so that you can work out what each one is at the other end. For the cable up the mast for the anchor light I used tinned marine cable, as it is less prone to corrosion of the copper wires in a saline environment. I don't think that this is necessary down below though. Any decent textbook on Yacht wiring [and there are a number around] will give you what size of wire you will need to carry the expected current. Actually, bell-wire will do for most purposes, as the wattage for lamps etc, will be quite small. You could make it even smaller by converting your lamps to LEDs and saving the drain on your battery as well. I converted all my lamps, cabin and nav to LEDs without a problem. I wrote a 'how-to' on it for CB quite a while ago.
Peter.
 
I rewired, well, I finished what the previous owner staered, on my boat 6 years ago, every inch of wire is tinned 'Cobra' wire, so far, in 6 years I have never had an electrical fault.

Tinned wire worth using IMHO.
 
I rewired my deck mounted navigation lights with good quality automotive wire. Three years later I had to do the job again as the wires were rotting so I did it properly with tinned wire.

It really is worth doing the job with the correct materials first time round. In 20 years tinned wire will still be in good condition and the automotive stuff will have failed at times and probably be due for the third rewire.

As each wire is threaded through it is easy enough to colour code the ends useing different colours/combinations of insulation tape.

Wireing up a boat is probably my favourite job, antifouling being my least favourite!
 
Thanks gents.
I can see the sense in using tinned wire - shame about the drum of un-tinned I was given - especially for that which goes up the mast etc., but I'm still hazy about the size of wire required. I have Alastair Garrod's book 'Electrics Afloat', which I think is extremely good, however I can't find advice on cable size or an equation for calculating it. P'raps I need to go through it again
 
When we re-wired White Heather I was able to get hold of some 'festoon' cable. This is the stuff you see on Blackpool Seafront driving a string of coloured bulbs. It has the advantage that its two conductor double insulated, 2.5 mm\2 which is a good cross sectional area for the long runs in a boat. you also get the feed and return in the same double sheath package. The conductors are multi filliment tinned copper.

Its about the same size and shape and domestic PVC twin and earth but the insulation is more like rubber - possibly butyl rubber? rather than PVC due to the fact that of course it is directly exposed to sunlight in its normal use.

It might be worth a visit to your local electrical wholesaler to have a look at some and guage how the costs would compare with the marine stuff.

I was toying with the idea of stripping off the second layer of insulation but in the end left it double insulated.

Hope this helps.

Mike
 
I'd use military surplus stuff .. try "thexmod". It is tough, and has a large number of strands which is needed to withstand vibration. Do use crimp terminals and/or bootlace ferrules when terminating it too. Tip: never solder then crimp or fit in any compression type terminals. The solder will "cold-flow" and leave you with loose connections. The ferrules will keep all the strands in place, and give you extra strain relief on the wires.
S.
 
Well good luck - but once done you will look back on it and be surprised how easy (if time consuming) it is.

Good quality cables etc are the key - don't economise whit this as re-doing the job in 5 years etc would be heartbreaking. As to thickness - if in doubt - go thicker -yes it will cost a little more -but negligible compared with the time taken to fit anything - as to tinned -essential to do it properly - but must admit I used (and have always) soldered connectors with glue impregnated heat shrink sleeving - unless in a high vibration area.

The solder ensures no corrosion at the connection (most likely point for failure /voltage drop) and the sleeve prevents undue stress /flexing of the (admittedly) more brittle solder/ copper conductor interface. I dare say some will disagree with this method - but I am aware of the reasons for using crimp only - but as long as cable support and non high vibration areas are thus treated no failures on any that I've done on any boat, but have seen plenty of crimps with some corrosion where the two meet.


Last point - take the opportunity to upgrade your switch panel (and label everything cables included +diagram /notes )and consider MCBs rather then fuses - then one circuit - one breaker + the soldered connection cannot ever (ok should not) overheat etc and the wire drop out (as its often another criticism of soldering them)
 
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