the cables are all routed through the panels of the car so they shouldnt have been damaged but i'll check, and the positive and negative are correct. I think there must be some damage to the amp somehow

hi i no it is stupid but do u hav the pos and neg the right way
uther wise mack shuwer ther is no cuts un the wire as u hav had the back seats dawn u mit of traped it .did u nok the sub/amp wen it was out?:)

Put a nail in the fuse holder :) If amp goes bang or nail blows out its fooked.

Yeah I know that, what I meant was that there isnt a short before the +ve lead gets to the sub. If the sleeving had been damaged and it was shorting on the bodywork that would blow the 30A fuse straight away. So it must be something in the amp?

The line fuse will never go if the amp has a fuse that blows at a lower current.

Yet another electrical prob with my car.
I have an FLI trap12 active sub its got a built in amplifier like on the outside of the speaker enclosure.
The other day I took it out because I needed to put the back seat down so I took out the main fuse in the +ve cable from the battery and then removed the cables from the sub. When I plug it back in and reinsert the fuse into the holder all seems ok, I turn electrics on to turn on head unit turn it up and the sub isnt working. The 20a fuse in the amplifier has gone (not the one inline on the +ve cable thats 30A) so i take it out and as i go to replace it BANG the fuse blows straight away. I then disconnected the negative from the battery
put a new fuse into the amp and reconnected the -ve, and it blew the fuse again? Any ideas, I think it must be an internal short in the amp otherwise the in line fuse would have gone right?

cheers

Chris