Hi there
I have just fitted splx 1000 amp and have used the original wiring in my punto that powered the factory fitted 100w sub, it works fine but when up loud for more than a few mins the amp cuts out and the red protection light comes on . Is this due to power cables to thin
Cheers

Most likely. There may be a chance that the amp is overheating too.

cheers mate

Get an upgraded wiring kit. probably short of power from battery. also turn the gain down so its about 1/2 or 3/4