Pardon my ignorance, but what scale does your country have as wire thickness scale?
I found this chart, not sure if it's helpful http://www.tnt-audio.com/clinica/awg_e.html
I have just ordered an Opus 150 and I have read a downloaded user manual in preparation for its arrival.
In the manual, it states to use 12 AWG wire for the + and - and 18 AWG wire for ignition or on/off.
What does 12 AWG and 18 AWG wire equate to in the UK ?
I found this which is even better. I guess you the rest of the world measure wire size in terms of mm.
So to answer your initial question:
12 gauge would be 2.02 mm diameter
18 gauge is 1.02 mm diameter
Thanks for the link Zip-Lock.
What ampage should 12 and 18 gauge be able to cope with. I was in a local car spares shop earlier today and their wire seemed to be rated by ampage and watts e.g. For example 17.5 amps or 210 Watts.
Given that the Opus is 150 Watt, would this be the correct wire to go for or should I go for a thicker wire.
I would use a 8 awg wire for + & - 12 awg is to small if you are going from the battery to the trunk and search this forum for tank circut you will need it here's a conversion chart http://www.lexproducts.com/wireconv.htm print it and keep it handy I know I will