Feed cables to anchor winch - what size please?

Cliveshep

Cliveshep

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Can anyone give me a definitive answer on this. I want to supply an anchor winch, 12v 45A (700W) length of run approx 25ft from battery bank. I assume that there will be a start-up load to factor in as well as run resistance. I am proposing to use domestic cable (for economy) in a cable duct under the side decks, just need to know what mm2 size I'll need. Boat operation is pretty much 100% fresh water so corrosion is unlikely to be a factor with untinned domestic multi-strand solid conductor cable such as 6 or 8mm for example.
 
I had an electric anchor winch fitted by engineer.He used a very HEAVY cable I don't know the specs but it was thicker than the stuff used on battery jump leads.I do not think that domestic cable will be satisfactory unless it is cooker type cable.Check with a supplier.
 
I was expecting larger than cooker, probably 10 or 25mm2 cable actually, I just need someone smart who can do the sums and advise the size as I cannot afford to let an engineer loose on it.
 
Minimum 15mm2...

15mm2 is about the minimum size - this will give you about 1V voltage drop, and you wouldn't want to drop more than that. 25mm2 would be a better choice.
 
ARC welding cable is the thing to use. It can carry the amperage and is flexible so installation will be easier.
 
If you want to keep it to a 2.5% volt drop (which you should), then 25mm just about does it.
Tinned cable is best but for my money too expensive. Untinned multistrand flexible cable with crimped on connections, taped up with self amalgamating tape will be fine.
I rewired my trawler with this 10 years ago and no problems to date.

I have a ready reconner I knocked up when I was wiring the boat to calc cable sizes if you are interested?

Cheers Colin
 
I've just bought 50 mm2 welding cable for my 1200W windlass (that's the X-sect area that Lofrans recommend) from here. No doubt your 700W one will not need as heavy a cable - but these guys also sell 25 mm2 and 35 mm2.
 
I used 80mmsq for my 1000W lofrans. Minimal voltage drop.

Get welding cable from an electrical engineeers. Its very flexible and comes double sheathed which makes it easy to secure . Use blind terminal lugs and shrinkwrap the ends with hot melt ahesive loaded shrinkwrap tubes - I find Raychem kit is quite good.
 
Length of run is actually from the battery, to the winch, AND back again, so if battery is 25' from winch, cable run length is 50'!

ABYC standards calculation comes out at cabkle size of AWG 1.

Anthony
 
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