Log in
Article search:

Q & A

12V Wiring

Having now bought a 12v fridge to replace the old gas one, we have discovered there is no 12v wiring to the kitchen side of the boat. Now Hubby is an electrical engineer so installation won't be a problem
per-se but we need to know the following. Traditionally DC cables were red/black but is this still the case and if so where can we source it as drawing blanks? If it has changed, can you tell us the new colour codes? Also, is there a good book on marine electrics out there? He is keen to book a course but nothing available that he can attend until June but we really need the fridge installed before then. Thanks.

Asked by: Debbie Frankland  | 8.04pm, Monday 2 March

WW says:

Red and black are still the normal colours for positive and negative DC cabling, though other colours can be used if particularl identification is required.
For an electric fridge, a suggestion would be to measure the distance from the battery to the fridge and back and the total length in metres should be the cross sectional diameter of the wire... So if it's 12 metres, the use 12mm2 cross sectional area wire as a minimum. It might seem like overkill, but this helps stop the low-voltage cutout happening prematurely.
To reduce the voltage drop, it is preferable to wire the fridge directly to the battery (via the positive master switch and inline fuse as close to the switch connection as possible). If you go via a normal fuse panel, voltage drops tends to be much higher, unless you have good connections and a large supply cable to the fuse panel.
Most of the books to marine electrics are either American (so very different to UK systems) or based on yachts, which have very different requirements.
However, if you search for Tony Brooks training online you will find a wealth of information which is very useful for all boaters, from electrics through to engines, better than any book on marine electrics!
LE us know if we can be more help.

Mark Langley  | 9.21PM, Monday 2 March

You must log in to post an answer.